Bi Amp question

[vMike]

I am thinking of bi amping my speakers using the extra 2 amps on my 7.1
avr. Using the small v. large settings and adjusting the crossover, I can
adjust the active crossover for the smalls to 350hz (matching the speakers
crossover) so that the mids and tweeters primarily get upper frequencies.
I do not have the ability to adjust the high pass crossover for the larges
so the woofers will get the full range of frequencies which will then use
the speaker's passive crossover.

Is this limitation going to negate the benefits of biamping?

mike

[Don Pearce[_2_]]

On Thu, 22 Jan 2009 16:29:39 -0500, "vMike" >
wrote:

>I am thinking of bi amping my speakers using the extra 2 amps on my 7.1
>avr. Using the small v. large settings and adjusting the crossover, I can
>adjust the active crossover for the smalls to 350hz (matching the speakers
>crossover) so that the mids and tweeters primarily get upper frequencies.
>I do not have the ability to adjust the high pass crossover for the larges
>so the woofers will get the full range of frequencies which will then use
>the speaker's passive crossover.
>
>Is this limitation going to negate the benefits of biamping?
>
>mike
>
>
>

There are no benefits to biamping. Anything you may have been told to
the contrary is wrong. There are, however, plenty of things that can
go seriously bad when you biamp, from poor high/low matching to an
unexpected blast of mains hum destroying a tweeter.

d

[Kalman Rubinson[_3_]]

On Thu, 22 Jan 2009 16:29:39 -0500, "vMike" >
wrote:

>I am thinking of bi amping my speakers using the extra 2 amps on my 7.1
>avr. Using the small v. large settings and adjusting the crossover, I can
>adjust the active crossover for the smalls to 350hz (matching the speakers
>crossover) so that the mids and tweeters primarily get upper frequencies.
>I do not have the ability to adjust the high pass crossover for the larges
>so the woofers will get the full range of frequencies which will then use
>the speaker's passive crossover.
>
>Is this limitation going to negate the benefits of biamping?
>
>mike


I do not know what AVR you have but, typically, most do not offer any
crossover for biamping at all and the crossover you see in "small" is
for crossing over to the subwoofer(s). They generally output full
bandwidth signals over both amps and let the built-in crossover in the
speaker handle the distribution.

Thus, if you use this setting with a 350Hz crossover, the HF part of
your biamped speakers will get 350Hz and up, the LF part of your
biamped speakers will also get 350Hz and up and your sub(s) will get
350Hz and down. Not a good idea.

Kal

[vMike]

"Kalman Rubinson" > wrote in message
...
> On Thu, 22 Jan 2009 16:29:39 -0500, "vMike" >
> wrote:
>
>>I am thinking of bi amping my speakers using the extra 2 amps on my 7.1
>>avr. Using the small v. large settings and adjusting the crossover, I can
>>adjust the active crossover for the smalls to 350hz (matching the speakers
>>crossover) so that the mids and tweeters primarily get upper frequencies.
>>I do not have the ability to adjust the high pass crossover for the larges
>>so the woofers will get the full range of frequencies which will then use
>>the speaker's passive crossover.
>>
>>Is this limitation going to negate the benefits of biamping?
>>
>>mike
>
>
> I do not know what AVR you have but, typically, most do not offer any
> crossover for biamping at all and the crossover you see in "small" is
> for crossing over to the subwoofer(s). They generally output full
> bandwidth signals over both amps and let the built-in crossover in the
> speaker handle the distribution.
>
> Thus, if you use this setting with a 350Hz crossover, the HF part of
> your biamped speakers will get 350Hz and up, the LF part of your
> biamped speakers will also get 350Hz and up and your sub(s) will get
> 350Hz and down. Not a good idea.
>
> Kal
>
Kal,
Thanks for the information. I currently have my sub disconnected and was
not planning to use it as my new speakers have plenty of bass. Also, my sub
has it's own amp and active crossover setting. The amp manual says the
crossover sets the frequency at which bass tones are removed from the small
main speakers and sent to the subwoofer line out. It further states that if
the speakers are set to large the entire frequency range is sent to the
speakers and the crossover is ignored whether I have a sub or not. Does
that change anything?

Mike

[jakdedert]

vMike wrote:
> "Kalman Rubinson" > wrote in message
> ...
>> On Thu, 22 Jan 2009 16:29:39 -0500, "vMike" >
>> wrote:
>>
>>> I am thinking of bi amping my speakers using the extra 2 amps on my 7.1
>>> avr. Using the small v. large settings and adjusting the crossover, I can
>>> adjust the active crossover for the smalls to 350hz (matching the speakers
>>> crossover) so that the mids and tweeters primarily get upper frequencies.
>>> I do not have the ability to adjust the high pass crossover for the larges
>>> so the woofers will get the full range of frequencies which will then use
>>> the speaker's passive crossover.
>>>
>>> Is this limitation going to negate the benefits of biamping?
>>>
>>> mike
>>
>> I do not know what AVR you have but, typically, most do not offer any
>> crossover for biamping at all and the crossover you see in "small" is
>> for crossing over to the subwoofer(s). They generally output full
>> bandwidth signals over both amps and let the built-in crossover in the
>> speaker handle the distribution.
>>
>> Thus, if you use this setting with a 350Hz crossover, the HF part of
>> your biamped speakers will get 350Hz and up, the LF part of your
>> biamped speakers will also get 350Hz and up and your sub(s) will get
>> 350Hz and down. Not a good idea.
>>
>> Kal
>>
> Kal,
> Thanks for the information. I currently have my sub disconnected and was
> not planning to use it as my new speakers have plenty of bass. Also, my sub
> has it's own amp and active crossover setting. The amp manual says the
> crossover sets the frequency at which bass tones are removed from the small
> main speakers and sent to the subwoofer line out. It further states that if
> the speakers are set to large the entire frequency range is sent to the
> speakers and the crossover is ignored whether I have a sub or not. Does
> that change anything?
>
> Mike
>
>
>
It sounds like a kludge, but maybe possible. The sub amps would
normally need to be larger than the the hi/mid amps. Disconnecting the
woofers from the passive crossover is also probably going to do some
funny things to the response. It would depend on the design of the
crossover just what that effect might be. It could be that it just
lowers or raises the low/mid cutoff, or it could toast components in the
x-over.

I don't think I'd try it. If you wanted to do it right, I'd think you'd
need to use a dedicated 2-way xover for the hi/mid pair--instead of just
disconnecting the low output of the 3-way--and roughly double the power
on the lows compared to the hi/mids.

If it were me, I'd just use the system as designed, with the active sub
crossed over way low...like 60 Hz or so. That's where many boxes begin
to drop off. If yours don't, and it's possible to go lower on the sub
x-over (most don't), then do it.

Play with it, work with the sub x-over frequency, level, phase, and
placement. You might like what you hear...or not.

jak

[Kalman Rubinson[_3_]]

On Thu, 22 Jan 2009 17:27:48 -0500, "vMike" >
wrote:

>
>"Kalman Rubinson" > wrote in message
...
>> On Thu, 22 Jan 2009 16:29:39 -0500, "vMike" >
>> wrote:
>>
>>>I am thinking of bi amping my speakers using the extra 2 amps on my 7.1
>>>avr. Using the small v. large settings and adjusting the crossover, I can
>>>adjust the active crossover for the smalls to 350hz (matching the speakers
>>>crossover) so that the mids and tweeters primarily get upper frequencies.
>>>I do not have the ability to adjust the high pass crossover for the larges
>>>so the woofers will get the full range of frequencies which will then use
>>>the speaker's passive crossover.
>>>
>>>Is this limitation going to negate the benefits of biamping?
>>>
>>>mike
>>
>>
>> I do not know what AVR you have but, typically, most do not offer any
>> crossover for biamping at all and the crossover you see in "small" is
>> for crossing over to the subwoofer(s). They generally output full
>> bandwidth signals over both amps and let the built-in crossover in the
>> speaker handle the distribution.
>>
>> Thus, if you use this setting with a 350Hz crossover, the HF part of
>> your biamped speakers will get 350Hz and up, the LF part of your
>> biamped speakers will also get 350Hz and up and your sub(s) will get
>> 350Hz and down. Not a good idea.
>>
>> Kal
>>
>Kal,
>Thanks for the information. I currently have my sub disconnected and was
>not planning to use it as my new speakers have plenty of bass. Also, my sub
>has it's own amp and active crossover setting. The amp manual says the
>crossover sets the frequency at which bass tones are removed from the small
>main speakers and sent to the subwoofer line out. It further states that if
>the speakers are set to large the entire frequency range is sent to the
>speakers and the crossover is ignored whether I have a sub or not. Does
>that change anything?
>
>Mike

Nope. Exactly what I would expect and completely in conformity with
what I described above. The controls on your sub are irrelevant since
they should be bypassed when used with the AVR. Also, there are very,
very few speakers that can do low bass better than a decent dedicated
sub and, moreover, using the sub will alleviate the workload for your
main speaker and amps.

Also, as others have stated, there's no reason to biamp unless the
original amp is completely inadequate. As stated above, using the suv
will help with that, too.

Kal

[Federico]

> There are no benefits to biamping. Anything you may have been told to
> the contrary is wrong. There are, however, plenty of things that can
> go seriously bad when you biamp, from poor high/low matching to an
> unexpected blast of mains hum destroying a tweeter.

Maybe there are no benefits this time.
But there are often mayor benefits in biamping.
F.

[Don Pearce[_2_]]

On Fri, 23 Jan 2009 10:24:12 +0100, "Federico" >
wrote:

>
>> There are no benefits to biamping. Anything you may have been told to
>> the contrary is wrong. There are, however, plenty of things that can
>> go seriously bad when you biamp, from poor high/low matching to an
>> unexpected blast of mains hum destroying a tweeter.
>
>Maybe there are no benefits this time.
>But there are often mayor benefits in biamping.
>F.
>

Like what? I have examined the subject in some detail, and I have yet
to find any. All I can find are disadvantages.

d

[Federico]

>>Maybe there are no benefits this time.
>>But there are often mayor benefits in biamping.
>>F.
>>
>
> Like what? I have examined the subject in some detail, and I have yet
> to find any. All I can find are disadvantages.


I remember the first time I listened to a biamped Martin LE400 monitor...
Huge difference then mono-amped.
http://www.martin-audio.com/specifications/oldproducts/LE400C/LE400Cdatasheet.pdf
F.

[Serge Auckland[_2_]]

"Federico" > wrote in message
. ..
>>>Maybe there are no benefits this time.
>>>But there are often mayor benefits in biamping.
>>>F.
>>>
>>
>> Like what? I have examined the subject in some detail, and I have yet
>> to find any. All I can find are disadvantages.
>
>
> I remember the first time I listened to a biamped Martin LE400 monitor...
> Huge difference then mono-amped.
> http://www.martin-audio.com/specifications/oldproducts/LE400C/LE400Cdatasheet.pdf
> F.
>
You're confusing Bi-amping with Active operation. Active operation, i.e.
using electronic crossovers before the power-amps, and no passive crossover
has many benefits, to do with headroom, accuracy of crossover, lower
distortions and avoidance of losses. Bi-amping, i.e. two power amps each
handling the full signal, and with passive crossovers retained have NO
benefit over a single amplifier unless that single amplifier is very poor to
the point of being broken.

In this regard, UK terminology i.e active and bi-amping seems more useful
than US terminology with refers just to biamping, sometimes correctly to
active biamping, but too often the word "active" is dropped.

S.
--
http://audiopages.googlepages.com

[Federico]

> In this regard, UK terminology i.e active and bi-amping seems more useful
> than US terminology with refers just to biamping, sometimes correctly to
> active biamping, but too often the word "active" is dropped.

Thanks for the explanation!
I've been sound engineering for 20 years and I never heard of "active
biamping" before.
That's what I usually call "biamping".
Sorry Don, you were right!
F.

[Arny Krueger]

"Serge Auckland" > wrote in
message

> "Federico" > wrote in message
> . ..

>>>> Maybe there are no benefits this time.
>>>> But there are often mayor benefits in biamping.
>>>> F.

There are two kinds of biamping - active biamping and passive bi-amping.

Active biamping is so called because of the use of an active as opposed to a
passive crossover.

Most of my life biamping has meant what is now called active biamping. Maybe
a decade ago I started hearing about this weird passive biamping, which
amounts to using the bi-wiring terminals on a speaker with a separate power
amp for each set of terminals. That splits the lower and upper range
sections of the speaker up, and allows people to vary the balance between
the two sections. This mostly happens accidentally. Since it creates an
audible difference, it is perceived by most who experiment with it, as an
improvement.

The two main laws of audio tweaking are:

1) If it does not in fact change anything audible, then it makes things
sound better.

2) If it does in fact change something that is audible, then it makes things
sound better.

;-)


>>> Like what? I have examined the subject in some detail,
>>> and I have yet to find any. All I can find are
>>> disadvantages.

On balance it does allow making very broad-brush changes to a systems
sonics. Its a very crude form of equalization.

>> I remember the first time I listened to a biamped Martin
>> LE400 monitor... Huge difference then mono-amped.
>> http://www.martin-audio.com/specifications/oldproducts/LE400C/LE400Cdatasheet.pdf
>> F.

More specifically:

"In active mode
the loudspeaker shall be bi-amped and operated with a
separate electronic controller. In passive mode, low and
high frequency sections shall be integrated by an
internal 1.2kHz passive crossover network."

The key phrase is "a separate electronic controller". IOW,an external active
crossover. However the design of this crossover is critical. None is
recommended and there is no documentation of how one would change the
performance of the loudspeaker.



> Bi-amping, i.e. two
> power amps each handling the full signal, and with
> passive crossovers retained have NO benefit over a single
> amplifier unless that single amplifier is very poor to
> the point of being broken.

Agreed.

> In this regard, UK terminology i.e active and bi-amping
> seems more useful than US terminology with refers just to
> biamping, sometimes correctly to active biamping, but too
> often the word "active" is dropped.

In US terminology, the distinction between the two modes can be made, if the
terminology is used properly. The dropping of either active or passive is
not a nationality thing, it is the responsibility of the individual poster.

[vMike]

"Kalman Rubinson" > wrote in message
...
> On Thu, 22 Jan 2009 17:27:48 -0500, "vMike" >
> wrote:
>
>>
>>"Kalman Rubinson" > wrote in message
...
>>> On Thu, 22 Jan 2009 16:29:39 -0500, "vMike" >
>>> wrote:
>>>
>>>>I am thinking of bi amping my speakers using the extra 2 amps on my 7.1
>>>>avr. Using the small v. large settings and adjusting the crossover, I
>>>>can
>>>>adjust the active crossover for the smalls to 350hz (matching the
>>>>speakers
>>>>crossover) so that the mids and tweeters primarily get upper
>>>>frequencies.
>>>>I do not have the ability to adjust the high pass crossover for the
>>>>larges
>>>>so the woofers will get the full range of frequencies which will then
>>>>use
>>>>the speaker's passive crossover.
>>>>
>>>>Is this limitation going to negate the benefits of biamping?
>>>>
>>>>mike
>>>
>>>
>>> I do not know what AVR you have but, typically, most do not offer any
>>> crossover for biamping at all and the crossover you see in "small" is
>>> for crossing over to the subwoofer(s). They generally output full
>>> bandwidth signals over both amps and let the built-in crossover in the
>>> speaker handle the distribution.
>>>
>>> Thus, if you use this setting with a 350Hz crossover, the HF part of
>>> your biamped speakers will get 350Hz and up, the LF part of your
>>> biamped speakers will also get 350Hz and up and your sub(s) will get
>>> 350Hz and down. Not a good idea.
>>>
>>> Kal
>>>
>>Kal,
>>Thanks for the information. I currently have my sub disconnected and was
>>not planning to use it as my new speakers have plenty of bass. Also, my
>>sub
>>has it's own amp and active crossover setting. The amp manual says the
>>crossover sets the frequency at which bass tones are removed from the
>>small
>>main speakers and sent to the subwoofer line out. It further states that
>>if
>>the speakers are set to large the entire frequency range is sent to the
>>speakers and the crossover is ignored whether I have a sub or not. Does
>>that change anything?
>>
>>Mike
>
> Nope. Exactly what I would expect and completely in conformity with
> what I described above. The controls on your sub are irrelevant since
> they should be bypassed when used with the AVR. Also, there are very,
> very few speakers that can do low bass better than a decent dedicated
> sub and, moreover, using the sub will alleviate the workload for your
> main speaker and amps.
>
> Also, as others have stated, there's no reason to biamp unless the
> original amp is completely inadequate. As stated above, using the suv
> will help with that, too.
>
> Kal
>
>
>
Thanks for your input. I just got new 802D's and they sound great, but I
was
thinking they might even sound better biamped as my amp is rated for only
150 and I had the extra amp in the system, but certainly don't want to
damage them. I think I will just leave it single amped. For now I have the
sub disconnected but will experiment with reconnecting with a very low
crossover.
mike

[vMike]

"Serge Auckland" > wrote in message
...
>
> "Federico" > wrote in message
> . ..
>>>>Maybe there are no benefits this time.
>>>>But there are often mayor benefits in biamping.
>>>>F.
>>>>
>>>
>>> Like what? I have examined the subject in some detail, and I have yet
>>> to find any. All I can find are disadvantages.
>>
>>
>> I remember the first time I listened to a biamped Martin LE400 monitor...
>> Huge difference then mono-amped.
>> http://www.martin-audio.com/specifications/oldproducts/LE400C/LE400Cdatasheet.pdf
>> F.
>>
> You're confusing Bi-amping with Active operation. Active operation, i.e.
> using electronic crossovers before the power-amps, and no passive
> crossover has many benefits, to do with headroom, accuracy of crossover,
> lower distortions and avoidance of losses. Bi-amping, i.e. two power amps
> each handling the full signal, and with passive crossovers retained have
> NO benefit over a single amplifier unless that single amplifier is very
> poor to the point of being broken.
>
> In this regard, UK terminology i.e active and bi-amping seems more useful
> than US terminology with refers just to biamping, sometimes correctly to
> active biamping, but too often the word "active" is dropped.
>
> S.
> --
> http://audiopages.googlepages.com
So if I can have active crossover on the tweeter and mid amp but passive on
the woofers amp, do you think there would be a benefit to biamping. My
speakers are 802D.

Mike

[Don Pearce[_2_]]

On Fri, 23 Jan 2009 08:44:07 -0500, "vMike" >
wrote:

>
>"Serge Auckland" > wrote in message
...
>>
>> "Federico" > wrote in message
>> . ..
>>>>>Maybe there are no benefits this time.
>>>>>But there are often mayor benefits in biamping.
>>>>>F.
>>>>>
>>>>
>>>> Like what? I have examined the subject in some detail, and I have yet
>>>> to find any. All I can find are disadvantages.
>>>
>>>
>>> I remember the first time I listened to a biamped Martin LE400 monitor...
>>> Huge difference then mono-amped.
>>> http://www.martin-audio.com/specifications/oldproducts/LE400C/LE400Cdatasheet.pdf
>>> F.
>>>
>> You're confusing Bi-amping with Active operation. Active operation, i.e.
>> using electronic crossovers before the power-amps, and no passive
>> crossover has many benefits, to do with headroom, accuracy of crossover,
>> lower distortions and avoidance of losses. Bi-amping, i.e. two power amps
>> each handling the full signal, and with passive crossovers retained have
>> NO benefit over a single amplifier unless that single amplifier is very
>> poor to the point of being broken.
>>
>> In this regard, UK terminology i.e active and bi-amping seems more useful
>> than US terminology with refers just to biamping, sometimes correctly to
>> active biamping, but too often the word "active" is dropped.
>>
>> S.
>> --
>> http://audiopages.googlepages.com
>So if I can have active crossover on the tweeter and mid amp but passive on
>the woofers amp, do you think there would be a benefit to biamping. My
>speakers are 802D.
>
>Mike
>

Let's examine the possible reasons for bi-amping:

1. Each amp handles a simpler signal, therefore distortion is less.
This holds no water. Signals are signals and amplifiers have no
knowledge of where they have been, and no preference for where they
will go. A signal containing both bass and treble is no harder to
handle than one containing just one of these.

2. You can drive the amplifiers harder. Again no. You don't divide the
power requirement in half when you split the signal. The power
requirement of an amplifier is determined by the peak voltage it must
deliver. For most music, this is unchanged by splitting the
frequencies - or rather some tunes will show higher treble levels,
while others show higher bass peaks. Those peaks are almost always as
big as the peaks in the combined signal, so all you are doing is
wasting power.

So much for bi-amping into a single speaker. There is a circumstance
where bi-amping is almost universal and very useful, and that is the
subwoofer. This is generally an add-on, not designed for the original
equipment and needs a range of adjustment to integrate it. Where the
subwoofer is integrated properly (the Willson Maxx speaker, for
example) there is again no reason to bi-amp, and a single amplifier
will do nicely.

d

[vMike]

<Don Pearce> wrote in message news:4979ca9b.87779703@localhost...
> On Fri, 23 Jan 2009 08:44:07 -0500, "vMike" >
> wrote:
>
>>
>>"Serge Auckland" > wrote in message
...
>>>
>>> "Federico" > wrote in message
>>> . ..
>>>>>>Maybe there are no benefits this time.
>>>>>>But there are often mayor benefits in biamping.
>>>>>>F.
>>>>>>
>>>>>
>>>>> Like what? I have examined the subject in some detail, and I have yet
>>>>> to find any. All I can find are disadvantages.
>>>>
>>>>
>>>> I remember the first time I listened to a biamped Martin LE400
>>>> monitor...
>>>> Huge difference then mono-amped.
>>>> http://www.martin-audio.com/specifications/oldproducts/LE400C/LE400Cdatasheet.pdf
>>>> F.
>>>>
>>> You're confusing Bi-amping with Active operation. Active operation, i.e.
>>> using electronic crossovers before the power-amps, and no passive
>>> crossover has many benefits, to do with headroom, accuracy of crossover,
>>> lower distortions and avoidance of losses. Bi-amping, i.e. two power
>>> amps
>>> each handling the full signal, and with passive crossovers retained have
>>> NO benefit over a single amplifier unless that single amplifier is very
>>> poor to the point of being broken.
>>>
>>> In this regard, UK terminology i.e active and bi-amping seems more
>>> useful
>>> than US terminology with refers just to biamping, sometimes correctly to
>>> active biamping, but too often the word "active" is dropped.
>>>
>>> S.
>>> --
>>> http://audiopages.googlepages.com
>>So if I can have active crossover on the tweeter and mid amp but passive
>>on
>>the woofers amp, do you think there would be a benefit to biamping. My
>>speakers are 802D.
>>
>>Mike
>>
>
> Let's examine the possible reasons for bi-amping:
>
> 1. Each amp handles a simpler signal, therefore distortion is less.
> This holds no water. Signals are signals and amplifiers have no
> knowledge of where they have been, and no preference for where they
> will go. A signal containing both bass and treble is no harder to
> handle than one containing just one of these.
>
> 2. You can drive the amplifiers harder. Again no. You don't divide the
> power requirement in half when you split the signal. The power
> requirement of an amplifier is determined by the peak voltage it must
> deliver. For most music, this is unchanged by splitting the
> frequencies - or rather some tunes will show higher treble levels,
> while others show higher bass peaks. Those peaks are almost always as
> big as the peaks in the combined signal, so all you are doing is
> wasting power.
>
> So much for bi-amping into a single speaker. There is a circumstance
> where bi-amping is almost universal and very useful, and that is the
> subwoofer. This is generally an add-on, not designed for the original
> equipment and needs a range of adjustment to integrate it. Where the
> subwoofer is integrated properly (the Willson Maxx speaker, for
> example) there is again no reason to bi-amp, and a single amplifier
> will do nicely.
>
> d
My understanding of the benefits of bi amp with active crossover (and this
may be incorrect) is that the passive crossover in the speaker sends small
amounts of current back to the amp through the speaker wires creating a
certain amount of distortion. Having active crossover with biamping
eliminates much of that distortion whereas having biamping with passive
crossover does nothing for that distortion.

Any thoughts on that?

mike

[Don Pearce[_2_]]

On Fri, 23 Jan 2009 09:03:32 -0500, "vMike" >
wrote:

>My understanding of the benefits of bi amp with active crossover (and this
>may be incorrect) is that the passive crossover in the speaker sends small
>amounts of current back to the amp through the speaker wires creating a
>certain amount of distortion. Having active crossover with biamping
>eliminates much of that distortion whereas having biamping with passive
>crossover does nothing for that distortion.
>
>Any thoughts on that?
>

Yes - it is incorrect. I'm not saying that all crossovers are entirely
free from distortion, but it is all relative. The speaker driver it is
feeding has distortion levels a hundred times as high.

The bit about sending tiny currents back, creating distortion is
actually technically incorrect too.

If you are really considering bi-amping in pursuit of better sound,
forget it. It isn't going to happen. All you will do is buy yourself
problems and grief getting it all set up. Spend the money on music.

d

[vMike]

<Don Pearce> wrote in message news:497acea0.88809281@localhost...
> On Fri, 23 Jan 2009 09:03:32 -0500, "vMike" >
> wrote:
>
>>My understanding of the benefits of bi amp with active crossover (and this
>>may be incorrect) is that the passive crossover in the speaker sends small
>>amounts of current back to the amp through the speaker wires creating a
>>certain amount of distortion. Having active crossover with biamping
>>eliminates much of that distortion whereas having biamping with passive
>>crossover does nothing for that distortion.
>>
>>Any thoughts on that?
>>
>
> Yes - it is incorrect. I'm not saying that all crossovers are entirely
> free from distortion, but it is all relative. The speaker driver it is
> feeding has distortion levels a hundred times as high.
>
> The bit about sending tiny currents back, creating distortion is
> actually technically incorrect too.
>
> If you are really considering bi-amping in pursuit of better sound,
> forget it. It isn't going to happen. All you will do is buy yourself
> problems and grief getting it all set up. Spend the money on music.
>
> d
ok enough said. I will leave things well enough alone. Music sounds great
already with what I have.
many thanks
mike

[[email protected]]

On Jan 23, 9:03*am, "vMike" > wrote:
> My understanding of the benefits of bi amp with
> active crossover (and this may be incorrect) is that
> the passive crossover in the speaker sends small
> amounts of current back to the amp through the
> speaker wires creating a certain amount of distortion. *
> Having active crossover with biamping eliminates
> much of that distortion whereas having biamping
> with passive crossover does nothing for that distortion.
>
> Any thoughts on that?

Yes, your understanding is incorrect on a number
of levels.

What the amplifier "sees" and how the load behaves
is not dependent upon individual components in
the speaker and its crossover, but on the sum total
of the load. ANd that is defined by the speaker's
impedance. The amplifier, the wires and all are utterly'
unaware of what causes individual features of that
electrical impedance, indeed, the only "individual
feature" of the impedance is the impedance.
And that impedance is not made any worse or better
by the presence of a competently designed speaker.

Second, the components of a passive crossover are far
and away, by orders of magnitude, more linear and thus
suffer from far less distortion than the drivers in the
speaker themselves.

Third, the vast majority of amplifiers that are even
moderately competently designed are essentially
insensitive to an extraordinary degree to the effects
of nonlinearities in the load as a matter of design.

Take all this together: IF you had an amplifier that
WAS sensitive to non-linear, nonresistive load
impedances, then, first, I would suggest you own
an incompetently designed or defective amplifier.
But if you STILL insisted on keeping it, then what
you'd find is that a reasonably competently
designed multi-way speaker with a passive
crossover would present a MORE linear, MORE
resistive and thus easier to drive load than you would
get with biamping.

And it would do it cheaper, more reliably and simpler.

[jakdedert]

Federico wrote:
>> In this regard, UK terminology i.e active and bi-amping seems more useful
>> than US terminology with refers just to biamping, sometimes correctly to
>> active biamping, but too often the word "active" is dropped.
>
> Thanks for the explanation!
> I've been sound engineering for 20 years and I never heard of "active
> biamping" before.
> That's what I usually call "biamping".
> Sorry Don, you were right!
> F.
>
>
I think it's all splitting hairs. The OP 'was' going to use an active
crossover. In fact, he has two: one in the receiver and one in the
subwoofer. Strictly speaking, just using a subwoofer is biamping,
although I usually think of it as splitting highs and lows at a much
higher frequency, it still fits the definition. 'Bi-wiring' is another
altogether different thing, that I never investigated; but AIU, doesn't
involve an active crossover.

I'm gonna go out on a limb (although a short and very stout one) and
define 'biamping' as using an active crossover ahead of two amplifier
channels with each reproducing a different part of the spectrum. It
doesn't matter whether there are additional passive filters after the
amplifier.

In fact, some professional sound reinforcement speakers are biamped
three-way designs, with a passive network to split the high/mids.
That's not so different from what the OP intended, although using a
three-way xover as a two way, by leaving the low output disconnected is
not indicated, IMO.

Also, it takes a lot more power to reproduce low frequencies, so the
amplifiers get progressively smaller as the frequency goes up. The old
rule of thumb used to be: double the power for mids as for highs, and
doubled again for the lows. IOW, (for example) 300 watts for lows, 150
for mids and 75 for highs. That was 'back when', and was never more
than a rough guide. Many variables are involved; xover frequencies,
power handling and relative efficiencies of the various sections
etc...but could get you at least somewhere near the ballpark.

jak

[Kalman Rubinson[_3_]]

On Fri, 23 Jan 2009 08:37:55 -0500, "vMike"
> wrote:


>Thanks for your input. I just got new 802D's and they sound great, but I
>was
>thinking they might even sound better biamped as my amp is rated for only
>150 and I had the extra amp in the system, but certainly don't want to
>damage them. I think I will just leave it single amped. For now I have the
>sub disconnected but will experiment with reconnecting with a very low
>crossover.

I have 802Ds also and strongly recommend that you do NOT
biamp them. The inbuilt crossovers are customized and
specialized and cannot be supplanted or improved on by
standard off-the-shelf external crossovers. Besides, in
order to do so, you would have to eviscerate your 802Ds and
remove the inbuilt crossovers to prevent interaction between
them and the new external crossover.

IMHO, decent 150w should be OK for the 802Ds but is not
generous. I am more comfortable with 200-500w in my system.
All that depends on your room, program material and
listening preferences. Certainly, adding the subwoofer so
that the lowest frequencies are rerouted to the sub will
make that 150w even more effective.

If after all is said and done, you feel the need for more
power, simply add a really good and powerful amp in place of
the one that is in your system now.

Kal

[Trevor Wilson[_2_]]

<Don Pearce> wrote in message news:4978ebf2.30778437@localhost...
> On Thu, 22 Jan 2009 16:29:39 -0500, "vMike" >
> wrote:
>
>>I am thinking of bi amping my speakers using the extra 2 amps on my 7.1
>>avr. Using the small v. large settings and adjusting the crossover, I can
>>adjust the active crossover for the smalls to 350hz (matching the speakers
>>crossover) so that the mids and tweeters primarily get upper frequencies.
>>I do not have the ability to adjust the high pass crossover for the larges
>>so the woofers will get the full range of frequencies which will then use
>>the speaker's passive crossover.
>>
>>Is this limitation going to negate the benefits of biamping?
>>
>>mike
>>
>>
>>
>
> There are no benefits to biamping.

**WTF?!!???!!! There *may* be huge benefits to biamp some speakers. Huge,
massive, instantly noticable benefits. Two, small amps, can easily be shown,
under certain circumstances, to outperform a much larger amp. In theory and
in practice.

Anything you may have been told to
> the contrary is wrong. There are, however, plenty of things that can
> go seriously bad when you biamp, from poor high/low matching to an
> unexpected blast of mains hum destroying a tweeter.

**********. A series capacitor will sort that issue out. In fact, many
speaker manufacturers, whose speakers are already set up for bi-amping
maintain such a cap for just such a purpose.


--
Trevor Wilson
www.rageaudio.com.au

[Trevor Wilson[_2_]]

"vMike" > wrote in message
...
>
> <Don Pearce> wrote in message news:4979ca9b.87779703@localhost...
>> On Fri, 23 Jan 2009 08:44:07 -0500, "vMike" >
>> wrote:
>>
>>>
>>>"Serge Auckland" > wrote in message
...
>>>>
>>>> "Federico" > wrote in message
>>>> . ..
>>>>>>>Maybe there are no benefits this time.
>>>>>>>But there are often mayor benefits in biamping.
>>>>>>>F.
>>>>>>>
>>>>>>
>>>>>> Like what? I have examined the subject in some detail, and I have yet
>>>>>> to find any. All I can find are disadvantages.
>>>>>
>>>>>
>>>>> I remember the first time I listened to a biamped Martin LE400
>>>>> monitor...
>>>>> Huge difference then mono-amped.
>>>>> http://www.martin-audio.com/specifications/oldproducts/LE400C/LE400Cdatasheet.pdf
>>>>> F.
>>>>>
>>>> You're confusing Bi-amping with Active operation. Active operation,
>>>> i.e.
>>>> using electronic crossovers before the power-amps, and no passive
>>>> crossover has many benefits, to do with headroom, accuracy of
>>>> crossover,
>>>> lower distortions and avoidance of losses. Bi-amping, i.e. two power
>>>> amps
>>>> each handling the full signal, and with passive crossovers retained
>>>> have
>>>> NO benefit over a single amplifier unless that single amplifier is very
>>>> poor to the point of being broken.
>>>>
>>>> In this regard, UK terminology i.e active and bi-amping seems more
>>>> useful
>>>> than US terminology with refers just to biamping, sometimes correctly
>>>> to
>>>> active biamping, but too often the word "active" is dropped.
>>>>
>>>> S.
>>>> --
>>>> http://audiopages.googlepages.com
>>>So if I can have active crossover on the tweeter and mid amp but passive
>>>on
>>>the woofers amp, do you think there would be a benefit to biamping. My
>>>speakers are 802D.
>>>
>>>Mike
>>>
>>
>> Let's examine the possible reasons for bi-amping:
>>
>> 1. Each amp handles a simpler signal, therefore distortion is less.
>> This holds no water. Signals are signals and amplifiers have no
>> knowledge of where they have been, and no preference for where they
>> will go. A signal containing both bass and treble is no harder to
>> handle than one containing just one of these.
>>
>> 2. You can drive the amplifiers harder. Again no. You don't divide the
>> power requirement in half when you split the signal. The power
>> requirement of an amplifier is determined by the peak voltage it must
>> deliver. For most music, this is unchanged by splitting the
>> frequencies - or rather some tunes will show higher treble levels,
>> while others show higher bass peaks. Those peaks are almost always as
>> big as the peaks in the combined signal, so all you are doing is
>> wasting power.
>>
>> So much for bi-amping into a single speaker. There is a circumstance
>> where bi-amping is almost universal and very useful, and that is the
>> subwoofer. This is generally an add-on, not designed for the original
>> equipment and needs a range of adjustment to integrate it. Where the
>> subwoofer is integrated properly (the Willson Maxx speaker, for
>> example) there is again no reason to bi-amp, and a single amplifier
>> will do nicely.
>>
>> d
> My understanding of the benefits of bi amp with active crossover (and this
> may be incorrect) is that the passive crossover in the speaker sends small
> amounts of current back to the amp through the speaker wires creating a
> certain amount of distortion. Having active crossover with biamping
> eliminates much of that distortion whereas having biamping with passive
> crossover does nothing for that distortion.

**No. Not correct. Bi-amping does impart some serous benefits to some
systems, however. To explain the advantages of bi-amping, I really need to
draw pretty pictures, but, I'll explain as best as I am able:

First off: Ignore the issue of POWER. We need to concentrate on Volts and
Amps (yes, I know power is a product of the two).

Image a hypothetical 30 Hz bass signal of (say) 60 Volts p-p. This
corresponds to 56 Watts continuous (@ 8 Ohms).
Imagine that at the same time, the amplifier must also deliver a 3kHz HF
signal of (say) 40 Volts p-p. This corresponds to 25 Watts (@ 8 Ohms)

All very well, you might say, as this is well within the capabilities of
your (hypothetical) 100 Watt (@ 8 Ohm) amplifier.

Not so fast.

Thanks to 'superposition' the p-p Voltages need to be added together first.
This will give us a total envelope of 100 Volts p-p. 100 Volts p-p is
equivalent to 156 Watts @ 8 Ohms.

Result - Voltage limiting (aka: Clipping).

In the above example, a 60 watt amp for bass and a 40 Watt amp for HF *may*
be more suitable (under the specific circumstances above) than a larger amp.

There are good reasons why every large sound reinforcement system is
multi-amped. It conveys serious advantages in power capacity and crossover
flexibility.

NB: None of these advantages may necessarily be realised in a domestic
situation. I have, however, worked on a number of domestic systems
(admittedly, quite large and power hungry ones) where multi-amping worked
exceptionally well.

The above assumes, of course, that a proper external crossover is used.


--
Trevor Wilson
www.rageaudio.com.au

[Don Pearce[_2_]]

On Sat, 24 Jan 2009 11:47:50 +1100, "Trevor Wilson"
> wrote:

>> There are no benefits to biamping.
>
>**WTF?!!???!!! There *may* be huge benefits to biamp some speakers. Huge,
>massive, instantly noticable benefits. Two, small amps, can easily be shown,
>under certain circumstances, to outperform a much larger amp. In theory and
>in practice.

Wrong. Theory says no such thing, and neither does practice. Unless
you have a very peculiar "certain circumstances", which I think we are
probably not discussing - just normal audio reproduction.

d

[Trevor Wilson[_2_]]

<Don Pearce> wrote in message news:497accaa.153843093@localhost...
> On Sat, 24 Jan 2009 11:47:50 +1100, "Trevor Wilson"
> > wrote:
>
>>> There are no benefits to biamping.
>>
>>**WTF?!!???!!! There *may* be huge benefits to biamp some speakers. Huge,
>>massive, instantly noticable benefits. Two, small amps, can easily be
>>shown,
>>under certain circumstances, to outperform a much larger amp. In theory
>>and
>>in practice.
>
> Wrong.

**Nope. Absolutely correct.

Theory says no such thing, and neither does practice.

**Sure it does. Hit your old text books and look up: 'Superposition'. The
practice is evidenced by thousands of professional sound reinforcement
systems, which use bi-amping.

Unless
> you have a very peculiar "certain circumstances", which I think we are
> probably not discussing - just normal audio reproduction.

**Just ordinary audio reproduction. Biamping can be shown to work. See my
other post. I'll even post some CRO shots I took last week to demonstrate
the principle.

Go to alt.binaries.schematics.electronics. Look for the post entitled:
Bi-Amping. There are three CRO photos in the post. It is pretty much
self-explanatory.


--
Trevor Wilson
www.rageaudio.com.au

[Don Pearce[_2_]]

On Sat, 24 Jan 2009 20:10:25 +1100, "Trevor Wilson"
> wrote:

>
>
>
><Don Pearce> wrote in message news:497accaa.153843093@localhost...
>> On Sat, 24 Jan 2009 11:47:50 +1100, "Trevor Wilson"
>> > wrote:
>>
>>>> There are no benefits to biamping.
>>>
>>>**WTF?!!???!!! There *may* be huge benefits to biamp some speakers. Huge,
>>>massive, instantly noticable benefits. Two, small amps, can easily be
>>>shown,
>>>under certain circumstances, to outperform a much larger amp. In theory
>>>and
>>>in practice.
>>
>> Wrong.
>
>**Nope. Absolutely correct.
>
> Theory says no such thing, and neither does practice.
>
>**Sure it does. Hit your old text books and look up: 'Superposition'. The
>practice is evidenced by thousands of professional sound reinforcement
>systems, which use bi-amping.
>

I know exactly what superposition is - it is the linear addition of
waveforms. Superposition is exactly what tells you that you don't need
to bi-amp. And of course if it was technically necessary (or
beneficial) to bi-amp, then simply doing that would make no sense -
hundreds of amps would be what you need.

>Unless
>> you have a very peculiar "certain circumstances", which I think we are
>> probably not discussing - just normal audio reproduction.
>
>**Just ordinary audio reproduction. Biamping can be shown to work. See my
>other post. I'll even post some CRO shots I took last week to demonstrate
>the principle.
>
>Go to alt.binaries.schematics.electronics. Look for the post entitled:
>Bi-Amping. There are three CRO photos in the post. It is pretty much
>self-explanatory.

My news service is text only. Put them somewhere (your web space) I
can see them and I will have a look. But I will say right now that if
you can see the "problem" on a CRO then you have some other really
serious problem, because a CRO is far too blunt a tool to see small
audio nuances.

d

[Trevor Wilson[_2_]]

<Don Pearce> wrote in message news:497bdbbb.157700203@localhost...
> On Sat, 24 Jan 2009 20:10:25 +1100, "Trevor Wilson"
> > wrote:
>
>>
>>
>>
>><Don Pearce> wrote in message news:497accaa.153843093@localhost...
>>> On Sat, 24 Jan 2009 11:47:50 +1100, "Trevor Wilson"
>>> > wrote:
>>>
>>>>> There are no benefits to biamping.
>>>>
>>>>**WTF?!!???!!! There *may* be huge benefits to biamp some speakers.
>>>>Huge,
>>>>massive, instantly noticable benefits. Two, small amps, can easily be
>>>>shown,
>>>>under certain circumstances, to outperform a much larger amp. In theory
>>>>and
>>>>in practice.
>>>
>>> Wrong.
>>
>>**Nope. Absolutely correct.
>>
>> Theory says no such thing, and neither does practice.
>>
>>**Sure it does. Hit your old text books and look up: 'Superposition'. The
>>practice is evidenced by thousands of professional sound reinforcement
>>systems, which use bi-amping.
>>
>
> I know exactly what superposition is - it is the linear addition of
> waveforms.

**Then you know why bi-amping *may* be helpful.

Superposition is exactly what tells you that you don't need
> to bi-amp. And of course if it was technically necessary (or
> beneficial) to bi-amp, then simply doing that would make no sense -
> hundreds of amps would be what you need.

**I take your point, but big sound reinforcement systems may use upwards of
seven or eight crossover points and amplifiers for each. In fact, I've seen
quite a few recent, surround sound amps which use bi or tri-amping. I
promise you: The ONLY reason these guys do it, is to reduce costs.

>
>>Unless
>>> you have a very peculiar "certain circumstances", which I think we are
>>> probably not discussing - just normal audio reproduction.
>>
>>**Just ordinary audio reproduction. Biamping can be shown to work. See my
>>other post. I'll even post some CRO shots I took last week to demonstrate
>>the principle.
>>
>>Go to alt.binaries.schematics.electronics. Look for the post entitled:
>>Bi-Amping. There are three CRO photos in the post. It is pretty much
>>self-explanatory.
>
> My news service is text only. Put them somewhere (your web space) I
> can see them and I will have a look. But I will say right now that if
> you can see the "problem" on a CRO then you have some other really
> serious problem, because a CRO is far too blunt a tool to see small
> audio nuances.

**It's not a small audio nuance. It can be, system depending, a dramatic and
substantial difference. I'll whack 'em up on my site tomorrow. It's not as
easy as posting to a newsgroup.


--
Trevor Wilson
www.rageaudio.com.au

[Don Pearce[_2_]]

On Sat, 24 Jan 2009 20:40:25 +1100, "Trevor Wilson"
> wrote:

>
>
>
><Don Pearce> wrote in message news:497bdbbb.157700203@localhost...
>> On Sat, 24 Jan 2009 20:10:25 +1100, "Trevor Wilson"
>> > wrote:
>>
>>>
>>>
>>>
>>><Don Pearce> wrote in message news:497accaa.153843093@localhost...
>>>> On Sat, 24 Jan 2009 11:47:50 +1100, "Trevor Wilson"
>>>> > wrote:
>>>>
>>>>>> There are no benefits to biamping.
>>>>>
>>>>>**WTF?!!???!!! There *may* be huge benefits to biamp some speakers.
>>>>>Huge,
>>>>>massive, instantly noticable benefits. Two, small amps, can easily be
>>>>>shown,
>>>>>under certain circumstances, to outperform a much larger amp. In theory
>>>>>and
>>>>>in practice.
>>>>
>>>> Wrong.
>>>
>>>**Nope. Absolutely correct.
>>>
>>> Theory says no such thing, and neither does practice.
>>>
>>>**Sure it does. Hit your old text books and look up: 'Superposition'. The
>>>practice is evidenced by thousands of professional sound reinforcement
>>>systems, which use bi-amping.
>>>
>>
>> I know exactly what superposition is - it is the linear addition of
>> waveforms.
>
>**Then you know why bi-amping *may* be helpful.
>
> Superposition is exactly what tells you that you don't need
>> to bi-amp. And of course if it was technically necessary (or
>> beneficial) to bi-amp, then simply doing that would make no sense -
>> hundreds of amps would be what you need.
>
>**I take your point, but big sound reinforcement systems may use upwards of
>seven or eight crossover points and amplifiers for each. In fact, I've seen
>quite a few recent, surround sound amps which use bi or tri-amping. I
>promise you: The ONLY reason these guys do it, is to reduce costs.
>

These are systems in which you need individual control - from the
console - of levels to all the individual speakers in order to
successfully ring out the system in each new venue. It is not done
because it is better but because it is vital. It also ensures massive
redundancy so the whole thing doesn't fall silent when one amplifier
fails. This has nothing to do with bi-amping a domestic system.

>>
>>>Unless
>>>> you have a very peculiar "certain circumstances", which I think we are
>>>> probably not discussing - just normal audio reproduction.
>>>
>>>**Just ordinary audio reproduction. Biamping can be shown to work. See my
>>>other post. I'll even post some CRO shots I took last week to demonstrate
>>>the principle.
>>>
>>>Go to alt.binaries.schematics.electronics. Look for the post entitled:
>>>Bi-Amping. There are three CRO photos in the post. It is pretty much
>>>self-explanatory.
>>
>> My news service is text only. Put them somewhere (your web space) I
>> can see them and I will have a look. But I will say right now that if
>> you can see the "problem" on a CRO then you have some other really
>> serious problem, because a CRO is far too blunt a tool to see small
>> audio nuances.
>
>**It's not a small audio nuance. It can be, system depending, a dramatic and
>substantial difference. I'll whack 'em up on my site tomorrow. It's not as
>easy as posting to a newsgroup.

I look forwards to it.

d

[Peter Larsen[_3_]]

Trevor Wilson > wrote:

> <Don Pearce> wrote in message news:4978ebf2.30778437@localhost...

>> On Thu, 22 Jan 2009 16:29:39 -0500, "vMike"

>> > wrote:

>>> I am thinking of bi amping my speakers using the extra 2 amps on
>>> my 7.1 avr. Using the small v. large settings and adjusting the
>>> crossover, I can adjust the active crossover for the smalls to
>>> 350hz (matching the speakers crossover) so that the mids and
>>> tweeters primarily get upper frequencies. I do not have the ability
>>> to adjust the high pass crossover for the larges so the woofers
>>> will get the full range of frequencies which will then use the
>>> speaker's passive crossover.

>>> Is this limitation going to negate the benefits of biamping?

Just biampling is in my opinion plain silly. If you want to use a dedicated
amplifier for each loudspeaker unit, then do it right. Rignt means that you
should use an active cross-over and the means required to ensure that the
acoustic output from each and every loudspeaker unit is exactly what the
filter math says it should be. There is no less work in optimizing an active
filter than in optimizing a passive high level filter, some loudspeaker
design software can do both.

>>> mike


Kind regards

Peter Larsen

[Kalman Rubinson]

On Sat, 24 Jan 2009 11:47:50 +1100, "Trevor Wilson"
> wrote:

>**WTF?!!???!!! There *may* be huge benefits to biamp some speakers. Huge,
>massive, instantly noticable benefits. Two, small amps, can easily be shown,
>under certain circumstances, to outperform a much larger amp. In theory and
>in practice.
>
> Anything you may have been told to
>> the contrary is wrong. There are, however, plenty of things that can
>> go seriously bad when you biamp, from poor high/low matching to an
>> unexpected blast of mains hum destroying a tweeter.
>
>**********. A series capacitor will sort that issue out. In fact, many
>speaker manufacturers, whose speakers are already set up for bi-amping
>maintain such a cap for just such a purpose.

[Trevor Wilson[_2_]]

<Don Pearce> wrote in message news:497bdbbb.157700203@localhost...
> On Sat, 24 Jan 2009 20:10:25 +1100, "Trevor Wilson"
> > wrote:
>
>>
>>
>>
>><Don Pearce> wrote in message news:497accaa.153843093@localhost...
>>> On Sat, 24 Jan 2009 11:47:50 +1100, "Trevor Wilson"
>>> > wrote:
>>>
>>>>> There are no benefits to biamping.
>>>>
>>>>**WTF?!!???!!! There *may* be huge benefits to biamp some speakers.
>>>>Huge,
>>>>massive, instantly noticable benefits. Two, small amps, can easily be
>>>>shown,
>>>>under certain circumstances, to outperform a much larger amp. In theory
>>>>and
>>>>in practice.
>>>
>>> Wrong.
>>
>>**Nope. Absolutely correct.
>>
>> Theory says no such thing, and neither does practice.
>>
>>**Sure it does. Hit your old text books and look up: 'Superposition'. The
>>practice is evidenced by thousands of professional sound reinforcement
>>systems, which use bi-amping.
>>
>
> I know exactly what superposition is - it is the linear addition of
> waveforms. Superposition is exactly what tells you that you don't need
> to bi-amp. And of course if it was technically necessary (or
> beneficial) to bi-amp, then simply doing that would make no sense -
> hundreds of amps would be what you need.

**Dunno why I didn't think of this yesterday, but, as music becomes
progressively more complex, it becomes somewhat more like white noise. As a
consequence, more of the larger, LF Voltage peaks will be subtracted by HF
signals. Hundreds of amps will not be required.


--
Trevor Wilson
www.rageaudio.com.au

[Trevor Wilson[_2_]]

<Don Pearce> wrote in message news:497ce58c.160213187@localhost...
> On Sat, 24 Jan 2009 20:40:25 +1100, "Trevor Wilson"
> > wrote:
>
>>
>>
>>
>><Don Pearce> wrote in message news:497bdbbb.157700203@localhost...
>>> On Sat, 24 Jan 2009 20:10:25 +1100, "Trevor Wilson"
>>> > wrote:
>>>
>>>>
>>>>
>>>>
>>>><Don Pearce> wrote in message news:497accaa.153843093@localhost...
>>>>> On Sat, 24 Jan 2009 11:47:50 +1100, "Trevor Wilson"
>>>>> > wrote:
>>>>>
>>>>>>> There are no benefits to biamping.
>>>>>>
>>>>>>**WTF?!!???!!! There *may* be huge benefits to biamp some speakers.
>>>>>>Huge,
>>>>>>massive, instantly noticable benefits. Two, small amps, can easily be
>>>>>>shown,
>>>>>>under certain circumstances, to outperform a much larger amp. In
>>>>>>theory
>>>>>>and
>>>>>>in practice.
>>>>>
>>>>> Wrong.
>>>>
>>>>**Nope. Absolutely correct.
>>>>
>>>> Theory says no such thing, and neither does practice.
>>>>
>>>>**Sure it does. Hit your old text books and look up: 'Superposition'.
>>>>The
>>>>practice is evidenced by thousands of professional sound reinforcement
>>>>systems, which use bi-amping.
>>>>
>>>
>>> I know exactly what superposition is - it is the linear addition of
>>> waveforms.
>>
>>**Then you know why bi-amping *may* be helpful.
>>
>> Superposition is exactly what tells you that you don't need
>>> to bi-amp. And of course if it was technically necessary (or
>>> beneficial) to bi-amp, then simply doing that would make no sense -
>>> hundreds of amps would be what you need.
>>
>>**I take your point, but big sound reinforcement systems may use upwards
>>of
>>seven or eight crossover points and amplifiers for each. In fact, I've
>>seen
>>quite a few recent, surround sound amps which use bi or tri-amping. I
>>promise you: The ONLY reason these guys do it, is to reduce costs.
>>
>
> These are systems in which you need individual control - from the
> console - of levels to all the individual speakers in order to
> successfully ring out the system in each new venue. It is not done
> because it is better but because it is vital. It also ensures massive
> redundancy so the whole thing doesn't fall silent when one amplifier
> fails.

**It is also done, because significant SPLs are required.

> This has nothing to do with bi-amping a domestic system.

**That would depend on the domestic system.


--
Trevor Wilson
www.rageaudio.com.au

[Trevor Wilson[_2_]]

<Don Pearce> wrote in message news:497ce58c.160213187@localhost...
> On Sat, 24 Jan 2009 20:40:25 +1100, "Trevor Wilson"
> > wrote:
>
> I look forwards to it.

**Done. Go to:

www.rageaudio.com.au

Click on: Bi-amping.


--
Trevor Wilson
www.rageaudio.com.au

[Don Pearce[_2_]]

On Sun, 25 Jan 2009 08:57:12 +1100, "Trevor Wilson"
> wrote:

>
>
>
>
><Don Pearce> wrote in message news:497ce58c.160213187@localhost...
>> On Sat, 24 Jan 2009 20:40:25 +1100, "Trevor Wilson"
>> > wrote:
>>
>> I look forwards to it.
>
>**Done. Go to:
>
>www.rageaudio.com.au
>
>Click on: Bi-amping.

Yup - I was expecting to see something unexpected (if you see what I
mean), but I didn't. You just presented the pathological extreme case.

Here is some actual music. First the complete work - no crossover

http://81.174.169.10/odds/allfreq.gif

Now just the bass frequencies, crossover at 2.2kHz

http://81.174.169.10/odds/lowfreq.gif

Although the average power has dropped somewhat, the amplifier needed
to carry this signal is just the same as for the whole signal -
dictated of course by signal peaks.

And finally the HF, above 2.2kHz. Filtering is all done with a second
order crossover style filter.

http://81.174.169.10/odds/highfreq.gif

You absolutely need the full amplifier power for this part of the
signal - you can't get away with a lower power amp simply because the
LF signals have been stripped away.

And of course a single amplifier will do every bit as well as
bi-amping. The moral of the story is that it doesn't do to try to
extrapolate to the real world from sine waves.

Just FYI, the music is "I'm with you", a track by Avril Lavigne.

d

[Don Pearce[_2_]]

On Sun, 25 Jan 2009 08:13:44 +1100, "Trevor Wilson"
> wrote:

>
>
>
><Don Pearce> wrote in message news:497bdbbb.157700203@localhost...
>> On Sat, 24 Jan 2009 20:10:25 +1100, "Trevor Wilson"
>> > wrote:
>>
>>>
>>>
>>>
>>><Don Pearce> wrote in message news:497accaa.153843093@localhost...
>>>> On Sat, 24 Jan 2009 11:47:50 +1100, "Trevor Wilson"
>>>> > wrote:
>>>>
>>>>>> There are no benefits to biamping.
>>>>>
>>>>>**WTF?!!???!!! There *may* be huge benefits to biamp some speakers.
>>>>>Huge,
>>>>>massive, instantly noticable benefits. Two, small amps, can easily be
>>>>>shown,
>>>>>under certain circumstances, to outperform a much larger amp. In theory
>>>>>and
>>>>>in practice.
>>>>
>>>> Wrong.
>>>
>>>**Nope. Absolutely correct.
>>>
>>> Theory says no such thing, and neither does practice.
>>>
>>>**Sure it does. Hit your old text books and look up: 'Superposition'. The
>>>practice is evidenced by thousands of professional sound reinforcement
>>>systems, which use bi-amping.
>>>
>>
>> I know exactly what superposition is - it is the linear addition of
>> waveforms. Superposition is exactly what tells you that you don't need
>> to bi-amp. And of course if it was technically necessary (or
>> beneficial) to bi-amp, then simply doing that would make no sense -
>> hundreds of amps would be what you need.
>
>**Dunno why I didn't think of this yesterday, but, as music becomes
>progressively more complex, it becomes somewhat more like white noise. As a
>consequence, more of the larger, LF Voltage peaks will be subtracted by HF
>signals. Hundreds of amps will not be required.

Don't understand what you are saying - how does an HF signal subtract
an LF peak?

d

[Peter Larsen[_3_]]

Don Pearce wrote:

> Yup - I was expecting to see something unexpected (if you see what I
> mean), but I didn't. You just presented the pathological extreme case.

> Here is some actual music. First the complete work - no crossover

> http://81.174.169.10/odds/allfreq.gif

Another pathological extreme case, this one of loudification ... O;-) ...
but realistic enough as it is what goes over the counter; just another
brick.

> Just FYI, the music is "I'm with you", a track by Avril Lavigne.

> d

Kind regards

Peter Larsen

[Don Pearce[_2_]]

On Sat, 24 Jan 2009 23:33:00 +0100, "Peter Larsen"
> wrote:

>Don Pearce wrote:
>
>> Yup - I was expecting to see something unexpected (if you see what I
>> mean), but I didn't. You just presented the pathological extreme case.
>
>> Here is some actual music. First the complete work - no crossover
>
>> http://81.174.169.10/odds/allfreq.gif
>
>Another pathological extreme case, this one of loudification ... O;-) ...
>but realistic enough as it is what goes over the counter; just another
>brick.
>
Unfortunately not pathologically extreme, but very typical.

d

[Trevor Wilson[_2_]]

<Don Pearce> wrote in message news:497c94a9.205043093@localhost...
> On Sun, 25 Jan 2009 08:13:44 +1100, "Trevor Wilson"
> > wrote:
>
>>
>>
>>
>><Don Pearce> wrote in message news:497bdbbb.157700203@localhost...
>>> On Sat, 24 Jan 2009 20:10:25 +1100, "Trevor Wilson"
>>> > wrote:
>>>
>>>>
>>>>
>>>>
>>>><Don Pearce> wrote in message news:497accaa.153843093@localhost...
>>>>> On Sat, 24 Jan 2009 11:47:50 +1100, "Trevor Wilson"
>>>>> > wrote:
>>>>>
>>>>>>> There are no benefits to biamping.
>>>>>>
>>>>>>**WTF?!!???!!! There *may* be huge benefits to biamp some speakers.
>>>>>>Huge,
>>>>>>massive, instantly noticable benefits. Two, small amps, can easily be
>>>>>>shown,
>>>>>>under certain circumstances, to outperform a much larger amp. In
>>>>>>theory
>>>>>>and
>>>>>>in practice.
>>>>>
>>>>> Wrong.
>>>>
>>>>**Nope. Absolutely correct.
>>>>
>>>> Theory says no such thing, and neither does practice.
>>>>
>>>>**Sure it does. Hit your old text books and look up: 'Superposition'.
>>>>The
>>>>practice is evidenced by thousands of professional sound reinforcement
>>>>systems, which use bi-amping.
>>>>
>>>
>>> I know exactly what superposition is - it is the linear addition of
>>> waveforms. Superposition is exactly what tells you that you don't need
>>> to bi-amp. And of course if it was technically necessary (or
>>> beneficial) to bi-amp, then simply doing that would make no sense -
>>> hundreds of amps would be what you need.
>>
>>**Dunno why I didn't think of this yesterday, but, as music becomes
>>progressively more complex, it becomes somewhat more like white noise. As
>>a
>>consequence, more of the larger, LF Voltage peaks will be subtracted by HF
>>signals. Hundreds of amps will not be required.
>
> Don't understand what you are saying - how does an HF signal subtract
> an LF peak?

**Superposition.


--
Trevor Wilson
www.rageaudio.com.au

[Arny Krueger]

"Trevor Wilson" > wrote
in message
> <Don Pearce> wrote in message
> news:497ce58c.160213187@localhost...
>> On Sat, 24 Jan 2009 20:40:25 +1100, "Trevor Wilson"
>> > wrote:
>>
>> I look forwards to it.
>
> **Done. Go to:
>
> www.rageaudio.com.au
>
> Click on: Bi-amping.

3 scope traces, no text.

"page under construction'

[Arny Krueger]

<Don Pearce> wrote in message
news:497b908b.203989171@localhost

> Just FYI, the music is "I'm with you", a track by Avril
> Lavigne.

Must be atypical, because the example I did with a 4th order butterworth
crossover showed a nearly 7 dB difference, with the tweeter getting that
much less signal.

Also, tweeters are generally easier to make more efficient than woofers for
reasons relating to box size and the laws of physics.

If you biamp you get to at least benefit from the ability to make tweeters
more efficient than woofers.

[Trevor Wilson[_2_]]

"Arny Krueger" > wrote in message
...
> "Trevor Wilson" > wrote
> in message
>> <Don Pearce> wrote in message
>> news:497ce58c.160213187@localhost...
>>> On Sat, 24 Jan 2009 20:40:25 +1100, "Trevor Wilson"
>>> > wrote:
>>>
>>> I look forwards to it.
>>
>> **Done. Go to:
>>
>> www.rageaudio.com.au
>>
>> Click on: Bi-amping.
>
> 3 scope traces, no text.
>
> "page under construction'

**I supplied all the information in a post to Don in this thread. I have no
plans to keep the page on my site permanently.


--
Trevor Wilson
www.rageaudio.com.au

[Chris Hornbeck]

On Sat, 24 Jan 2009 22:30:03 -0500, "Arny Krueger" >
wrote:

>If you biamp you get to at least benefit from the ability to make tweeters
>more efficient than woofers.

And to amplify on this, although you will likely have personal
quibbles (and, probably pretty hard to argue with, in a modern
context), an amplifier can be made to be lower distortion if
made "smaller", for any given amount of money. A smaller but
faster amplifier for any given buck - like that.

"A sadder but wiser girl for me." Extra points for those old
enough to name the reference. Arf.


My larger bitch about this whole discussion is that it has
assumed that speaker drivers will both be fed by and behave
*the same* when fed directly from an amplifier's super-low-Z
output as from a high(speaker)-level crossover.

This assumption isn't really very true in the region where
it matters the most, in the region of the driver's fundamental
resonance. Here, a high/speaker-level ("passive") crossover interacts
in difficult ways with the drivers' impedances....

Stuff you and all serious folks know, natch.



There are important advantages to defining each of a loudspeaker's
drivers' individual driving voltages very carefully:

It's difficult-bordering-on-impossible to define individual
drivers' impedance interactions within the bandpass network
of the "crossover". From a network-analysis-kinda viewpoint
the whole thing stinks on ice.

IOW, ain't no such thing as a real engineering-quality "passive"
"crossover", because there's no such thing as an engineering-
quality "load" for that crossover. Drivers are both complex
reactances and motors, and the whole contraption wobbles.



Given the sketchy, wobbly, weird, wangly nature of loudspeaker
drivers, and their complicated interactions with *any* impedances
between their own Pure Selves and whatever passes for voltage-source
driving machines, AND whatever residual amplifier errors that
any particular techically-savvy-net-person considers to Signify...


And then we get into the territory of the proper shape(s) of
the crossover itself. Here hearts are won and lost, wars are
fought, but ultimately we all agree (...?).


If we really want to discuss this topic, we'll want to discuss
both the topics of loudspeaker summed responses from multiple
radiators (see, as always! Linkwitz - done it, been there several
decades before us) and musical distribution of energy, a moving
target.


Much thanks, as always,
Chris Hornbeck

[Don Pearce[_2_]]

On Sat, 24 Jan 2009 22:30:03 -0500, "Arny Krueger" >
wrote:

><Don Pearce> wrote in message
>news:497b908b.203989171@localhost
>
>> Just FYI, the music is "I'm with you", a track by Avril
>> Lavigne.
>
>Must be atypical, because the example I did with a 4th order butterworth
>crossover showed a nearly 7 dB difference, with the tweeter getting that
>much less signal.
>
>Also, tweeters are generally easier to make more efficient than woofers for
>reasons relating to box size and the laws of physics.
>
>If you biamp you get to at least benefit from the ability to make tweeters
>more efficient than woofers.
>
>

This is the point, really. Music is like that; some goes one way, some
goes the other and some stays pretty much the same. You can't
construct a rule that allows you to generalise about what power you
need for which bit of the spectrum. Interestingly, if you put a square
wave through a crossover filter, the power requirement of the highpass
amplifier can double.

The reason tweeters tend to be more efficient than woofers isn't so
much to do with box sizes and the laws of physics as the fact that
they don't have to move far when working so it is easy to keep the
entire voice coil immersed in the magnetic field.

But remember what we are talking about here - not a system we are
designing from scratch, but a purchased speaker which has already been
balanced internally, but offers bi-amp terminals.

d

[Arny Krueger]

"Chris Hornbeck" > wrote in
message
> On Sat, 24 Jan 2009 22:30:03 -0500, "Arny Krueger"
> > wrote:
>
>> If you biamp you get to at least benefit from the
>> ability to make tweeters more efficient than woofers.

> And to amplify on this, although you will likely have
> personal quibbles (and, probably pretty hard to argue
> with, in a modern context), an amplifier can be made to
> be lower distortion if made "smaller", for any given amount of money. A
> smaller
> but faster amplifier for any given buck - like that.

No quibble. It has always been easier and cheaper to make small, fast, high
gain transistors than big ones.

> My larger bitch about this whole discussion is that it has
> assumed that speaker drivers will both be fed by and
> behave *the same* when fed directly from an amplifier's
> super-low-Z output as from a high(speaker)-level crossover.

If you are free to design the drivers, then nominal (but not exceptional)
losses and source impedance issues in the crossover can be largely
compensated for.

> This assumption isn't really very true in the region where
> it matters the most, in the region of the driver's
> fundamental resonance. Here, a high/speaker-level
> ("passive") crossover interacts in difficult ways with
> the drivers' impedances....

It often is far more difficult to simply pay for crossover parts with
adequate quality. Furthermore, there are functions you might want to put
into the crossover that cost very little if implemented with a DSP, and cost
an arm or a leg or have egregious losses if implmented passively. Things
like phase shift networks and delays.

[jamesgangnc]

"vMike" > wrote in message
...
>
> <Don Pearce> wrote in message news:497acea0.88809281@localhost...
>> On Fri, 23 Jan 2009 09:03:32 -0500, "vMike" >
>> wrote:
>>
>>>My understanding of the benefits of bi amp with active crossover (and
>>>this
>>>may be incorrect) is that the passive crossover in the speaker sends
>>>small
>>>amounts of current back to the amp through the speaker wires creating a
>>>certain amount of distortion. Having active crossover with biamping
>>>eliminates much of that distortion whereas having biamping with passive
>>>crossover does nothing for that distortion.
>>>
>>>Any thoughts on that?
>>>
>>
>> Yes - it is incorrect. I'm not saying that all crossovers are entirely
>> free from distortion, but it is all relative. The speaker driver it is
>> feeding has distortion levels a hundred times as high.
>>
>> The bit about sending tiny currents back, creating distortion is
>> actually technically incorrect too.
>>
>> If you are really considering bi-amping in pursuit of better sound,
>> forget it. It isn't going to happen. All you will do is buy yourself
>> problems and grief getting it all set up. Spend the money on music.
>>
>> d
> ok enough said. I will leave things well enough alone. Music sounds great
> already with what I have.
> many thanks
> mike
>
I bi-amp with a dbx active crossover, an adcom 555 on the low end and an
adcom 535 on the high. I'm pleased with the results. I crossover around
350 hz with the low side powering 4 10" woofers and the high side running an
MTM style arrangement using a couple 5" mid-bass and a ribbon tweeter. One
nice thing is that you do not have to worry about speaker impedances as much
which makes it easier when using multiple speakers. The active crossovers
give you a lot of flexibility to play with crossover point that you do not
have with a passive crossover at the output.

[Edmund]

Don Pearce wrote:
> On Fri, 23 Jan 2009 09:03:32 -0500, "vMike" >
> wrote:
>
>> My understanding of the benefits of bi amp with active crossover (and this
>> may be incorrect) is that the passive crossover in the speaker sends small
>> amounts of current back to the amp through the speaker wires creating a
>> certain amount of distortion. Having active crossover with biamping
>> eliminates much of that distortion whereas having biamping with passive
>> crossover does nothing for that distortion.
>>
>> Any thoughts on that?
>>
>
> Yes - it is incorrect. I'm not saying that all crossovers are entirely
> free from distortion,

That is one way put it :-)
passive crossovers are pain in many ways, they introduce a LOT
of phase shift in the signal is such a way that the output from
these crossovers alone!! never gives the input signal back.

An other things is, without a passive network between the amp and
the speaker unit, the amp wil have way better control over the driver.
So that also is way better with active crossover and bi amping.

Then we have the power requirements, one amp driving the entire range
will have to be big enough to drive the bass. When the amp starts to
clip, the passive filters directs these distortion products to the
tweeter and they are very audible! No such thing happens with an active
system. BTW you need LESS power with bi amping too.




but it is all relative. The speaker driver it is
> feeding has distortion levels a hundred times as high.

Steep filters add a lot of distortion too.


>
> The bit about sending tiny currents back, creating distortion is
> actually technically incorrect too.

No it's not, the passive crossovers will shift phase and that IS
distortion.
( not that per se active crossovers will overcome that problem, but
some do )
>
> If you are really considering bi-amping in pursuit of better sound,
> forget it. It isn't going to happen. All you will do is buy yourself
> problems and grief getting it all set up. Spend the money on music.
>

I strongly disagree with almost everything you said.

> d

Edmund

[Don Pearce[_2_]]

On Wed, 28 Jan 2009 11:18:00 +0100, Edmund >
wrote:

>Don Pearce wrote:
>> On Fri, 23 Jan 2009 09:03:32 -0500, "vMike" >
>> wrote:
>>
>>> My understanding of the benefits of bi amp with active crossover (and this
>>> may be incorrect) is that the passive crossover in the speaker sends small
>>> amounts of current back to the amp through the speaker wires creating a
>>> certain amount of distortion. Having active crossover with biamping
>>> eliminates much of that distortion whereas having biamping with passive
>>> crossover does nothing for that distortion.
>>>
>>> Any thoughts on that?
>>>
>>
>> Yes - it is incorrect. I'm not saying that all crossovers are entirely
>> free from distortion,
>
>That is one way put it :-)
>passive crossovers are pain in many ways, they introduce a LOT
>of phase shift in the signal is such a way that the output from
>these crossovers alone!! never gives the input signal back.
>
Gibberish. They introduce no more phase shift than an active design of
similar slope. And it doesn't matter what signal they "give back"
[sic] because the amplifier has such a low output impedance that it is
shorted to ground.

>An other things is, without a passive network between the amp and
>the speaker unit, the amp wil have way better control over the driver.
>So that also is way better with active crossover and bi amping.
>
No it won't. The loss in a passive crossover is low enough that the
amplifier maintains full control. The ratio that matters is the
crossover resistance to the speaker resistance - more than adequate, I
can assure you. And of course when you bi-amp a domestic speaker the
crossover is still in circuit - all you do is split the input, so no
deal there either.

>Then we have the power requirements, one amp driving the entire range
>will have to be big enough to drive the bass. When the amp starts to
>clip, the passive filters directs these distortion products to the
>tweeter and they are very audible! No such thing happens with an active
>system. BTW you need LESS power with bi amping too.
>

Entirely wrong. First off, you don't drive amplifiers into clipping,
and if you find you are doing so, you need a bigger amplifier. And no,
with bi-amping you do not need less power. I have already demonstrated
this quite conclusively.

>
>
>
> but it is all relative. The speaker driver it is
>> feeding has distortion levels a hundred times as high.
>
>Steep filters add a lot of distortion too.
>

No they don't. Steep filters are as linear as shallow ones. Distortion
can only be added by non-linearity.

>
>>
>> The bit about sending tiny currents back, creating distortion is
>> actually technically incorrect too.
>
>No it's not, the passive crossovers will shift phase and that IS
>distortion.
>( not that per se active crossovers will overcome that problem, but
>some do )

Wrong on every count. Phase shift is NOT distortion - it is in fact
entirely inaudible. And active crossovers introduce the identical
phase shift to passive ones of similar slope.

>>
>> If you are really considering bi-amping in pursuit of better sound,
>> forget it. It isn't going to happen. All you will do is buy yourself
>> problems and grief getting it all set up. Spend the money on music.
>>
>
>I strongly disagree with almost everything you said.
>
>> d
>
>Edmund

Jolly good.

d

[Edmund]

vMike wrote:
> I am thinking of bi amping my speakers using the extra 2 amps on my 7.1
> avr. Using the small v. large settings and adjusting the crossover, I can
> adjust the active crossover for the smalls to 350hz (matching the speakers
> crossover) so that the mids and tweeters primarily get upper frequencies.
> I do not have the ability to adjust the high pass crossover for the larges
> so the woofers will get the full range of frequencies which will then use
> the speaker's passive crossover.
>
> Is this limitation going to negate the benefits of biamping?
>
> mike
>
>
>
>
In short.
One of the big advantages in a active system is that the am are direct
connected with the drivers. So make sure the amps are direct connected
to the drivers without the passive crossover stuff.
One big mistake often made with active systems is using a very steep
crossover just because it can. That isn't going to work very well, what
you need is a phase correct crossover.I don't know what 7.1 avr is and
what woofers you have but if you can wire it as I told you,you be fine.

Edmund

[Peter Larsen[_3_]]

Edmund > wrote:


> passive crossovers are pain in many ways, they introduce a LOT
> of phase shift in the signal is such a way that the output from
> these crossovers alone!! never gives the input signal back.

Totally irrelevant, what matters is whether the acoustic output sums
properly.

> An other things is, without a passive network between the amp and
> the speaker unit, the amp wil have way better control over the driver.
> So that also is way better with active crossover and bi amping.

A passive cross-over implies a high output impedance driving the units, at
least in the top.

> Then we have the power requirements, one amp driving the entire range
> will have to be big enough to drive the bass. When the amp starts to
> clip, the passive filters directs these distortion products to the
> tweeter and they are very audible!

Yees.

> No such thing happens with an active system.

Correct.

> BTW you need LESS power with bi amping too.

Too simplified, you need the same total amount of power delivered to the
units.

> Steep filters add a lot of distortion too.

No.

> No it's not, the passive crossovers will shift phase and that IS
> distortion.
> ( not that per se active crossovers will overcome that problem, but
> some do )

Phase shift per se is not an issue.

>> If you are really considering bi-amping in pursuit of better sound,
>> forget it. It isn't going to happen. All you will do is buy yourself
>> problems and grief getting it all set up. Spend the money on music.

For Joe user who has an iteratively optimized passive cross-over that is
entirely correct. A replacement active cross-over would need no less
optimization. Just plugging multiple amps into the existing passive
crossover is a concept that has merit for the amplifier sellers income only.

> I strongly disagree with almost everything you said.

We can't all agree with Don. The user he didn't allow for is Timmy the DIY
guy with a cookbook passive cross-over and no means to optimize it to the
actual system. He will be less bad off with an active. Biamping to me reads
as if no active cross-over is used, in which case the technical merit is at
best zero.

>> d

> Edmund

Kind regards

Peter Larsen

[Peter Larsen[_3_]]

Edmund > wrote:

> vMike wrote:

>> I am thinking of bi amping my speakers using the extra 2 amps on my
>> 7.1 avr. Using the small v. large settings and adjusting the
>> crossover, I can adjust the active crossover for the smalls to 350hz
>> (matching the speakers crossover) so that the mids and tweeters
>> primarily get upper frequencies. I do not have the ability to adjust
>> the high pass crossover for the larges so the woofers will get the
>> full range of frequencies which will then use the speaker's passive
>> crossover.

Get a proper cross-over then. Behringers DCX may be a candiate PROVIDED you
are qualified to align the system properly, including getting the line
levels right for good s-n ratio.

>> Is this limitation going to negate the benefits of biamping?

For a simple answer: that is not what those settings have as purpose. If you
want to experiment with an active cross-over, then get one.

>> mike

> One of the big advantages in a active system is that the am are direct
> connected with the drivers. So make sure the amps are direct connected
> to the drivers without the passive crossover stuff.

I tend to agree that loudspeaker drivers that are connected directly to an
amplifiers gives the best they can.

> One big mistake often made with active systems is using a very steep
> crossover just because it can. That isn't going to work very well,

Best active system I have heard yet crossed over at 200 dB pr. octave.

> what you need is a phase correct crossover.

What he needs is a crossover that matches his loudspeakers as system
consided and matches the requirements for making each and every unit perform
optimally.

> I don't know what 7.1 avr
> is

They guy is talking about finagling his el cheapo or somewhat costlio
surround receiver to use as cross-over. It is plain silly.

> and what woofers you have but if you can wire it as I told you, you
> be fine.

Allow me to suggest the OP's actual question before typing the answer. If
there be information lacking, then ask for it up front.

> Edmund

Kind regards

Peter Larsen

[[email protected]]

On Jan 28, 5:18*am, Edmund > wrote:
> passive crossovers are pain in many ways, they introduce a LOT
> of phase shift in the signal is such a way that the output from
> these crossovers alone!!

This is total nonsense. The phase shift of a crossover
is determined by its transfer function, NOT be how it
is implemented. Build a passive 2nd-order Butterworth
crossover, and you will find that its phase shift is
IDENTICAL to an actively implemented 2nd-order
butterworth. Do it again digitially, and the phase
shift will be, again IDENTICAL.

> never gives the input signal back.

The ability of a speaker to reconstruct its input signal
requires the ENTIRE system be designed as a system.
And it can be done as well with active and passive
networks, given a sufficiently skilled designer.

> An other things is, without a passive network between
> the amp and the speaker unit, the amp wil have way
> better control over the driver.

Nonsense again. The total series resistance in a
speaker is what controls damping, and that resistance
is dominated and, in most cases, overwhelmed by
the DC resistance of the voice coil winding, which is
most often more than an order of magnitude greater
than that inserted by series crossover components.

> So that also is way better with active crossover and
> bi amping.

No, it is not, and provably so.

> Steep filters add a lot of distortion too.

Are you just making this stuff up, or are you getting
it from someone who's just making it up?

> > The bit about sending tiny currents back, creating distortion is
> > actually technically incorrect too.
>
> No it's not,

Yes, it is. Please go study some real electrical
engineering principles before you spout this stuff off.

> the passive crossovers will shift phase and that IS
> distortion.

No it is not, ESPECIALLY when a competent designer
has designed the overall response of the network to be
the conjugate of the drivers.

> > If you are really considering bi-amping in pursuit of better sound,
> > forget it. It isn't going to happen. All you will do is buy yourself
> > problems and grief getting it all set up.
>
> I strongly disagree with almost everything you said.

And, with no disrespect intended, you do so from
from a position of technical ignorance.

[[email protected]]

On Jan 28, 5:34*am, Edmund > wrote:
> One of the big advantages in a active system is
> that the am are direct connected with the drivers.

They are with passive networks as well. You have some real
technical evidence to the contrary?

> One big mistake often made with active systems is
> using a very steep crossover just because it can.

No, the BIGGEST mistake is a blind belief in just
the points you have made. The BEST crossover is
the crossover that is SPECIFICALLY and EXCLUSIVELY
designed to work with the specific combination of drivers,
cabinets and all that go to make the speaker SYSTEM.
Secondary to this is whether it is passive or active.

The notion that one can simply go an get an active
crossover, hack it into an existing system and have
it work better is extremely naive and boneheaded.
A speaker is a SYSTEM, designed, hopefully, by
the designer who is aware of the response of the
drivers used in the way they are and then tailors
the design of the network to integrate them all
together. The crossover transfer function, topology
and implementation is chosen SPECIFICALLY to
compensate for the transfer function deviations of
the drivers.

The person designing the speaker SYSTEM has
a far better understanding of the requirements of
the SYSTEM than the personb whose designing
some generic active crossover. How on earth could
you think otherwise?

>That isn't going to work very well, what you need
> is a phase correct crossover.

What is "phase correct" other than technobabble?
Do you mean "linear phase" Do you mean "minimum
phase" Do you mean "conjugate phase?" What?

> I don't know what 7.1 avr is and
> what woofers you have but if you can wire it as
> I told you,you be fine.

Again, as a statement of fact, you have no idea,
in a technical sense, what you are talking about,
other than spouting popular culture and myth.

[Edmund]

Don Pearce wrote:
> On Wed, 28 Jan 2009 11:18:00 +0100, Edmund >
> wrote:
>
>> Don Pearce wrote:
>>> On Fri, 23 Jan 2009 09:03:32 -0500, "vMike" >
>>> wrote:
>>>
>>>> My understanding of the benefits of bi amp with active crossover (and this
>>>> may be incorrect) is that the passive crossover in the speaker sends small
>>>> amounts of current back to the amp through the speaker wires creating a
>>>> certain amount of distortion. Having active crossover with biamping
>>>> eliminates much of that distortion whereas having biamping with passive
>>>> crossover does nothing for that distortion.
>>>>
>>>> Any thoughts on that?
>>>>
>>> Yes - it is incorrect. I'm not saying that all crossovers are entirely
>>> free from distortion,
>> That is one way put it :-)
>> passive crossovers are pain in many ways, they introduce a LOT
>> of phase shift in the signal is such a way that the output from
>> these crossovers alone!! never gives the input signal back.
>>
> Gibberish. They introduce no more phase shift than an active design of
> similar slope.

That active crossovers have the same phase shift doesn't change
the fact that that is unwanted.
Enlish is not mu language and I was very unclear with "give the input
signal back" what I mean is, the sum of the output from a crossover
with phase shift, is never equal to the input signal and there is no way
to correct that with speaker units.

And making a passive filter requires big C's and L's, then there is the
tolerance of C's which makes it hard to get the required values end
keep values for some time.
these things are much easier to realize with an active crossover and
as I said, there are no C's and L's between the amp and the driver.



And it doesn't matter what signal they "give back"
> [sic] because the amplifier has such a low output impedance that it is
> shorted to ground.
>
>> An other things is, without a passive network between the amp and
>> the speaker unit, the amp wil have way better control over the driver.
>> So that also is way better with active crossover and bi amping.
>>
> No it won't. The loss in a passive crossover is low enough that the
> amplifier maintains full control. The ratio that matters is the
> crossover resistance to the speaker resistance - more than adequate, I
> can assure you. And of course when you bi-amp a domestic speaker the
> crossover is still in circuit - all you do is split the input, so no
> deal there either.
>
>> Then we have the power requirements, one amp driving the entire range
>> will have to be big enough to drive the bass. When the amp starts to
>> clip, the passive filters directs these distortion products to the
>> tweeter and they are very audible! No such thing happens with an active
>> system. BTW you need LESS power with bi amping too.
>>
>
> Entirely wrong. First off, you don't drive amplifiers into clipping,
> and if you find you are doing so, you need a bigger amplifier.

well I agree but clipping still happens.
o,
> with bi-amping you do not need less power. I have already demonstrated
> this quite conclusively.

How did you demonstrate that? it isn't true.

>
>>
>>
>> but it is all relative. The speaker driver it is
>>> feeding has distortion levels a hundred times as high.
>> Steep filters add a lot of distortion too.
>>
>
> No they don't. Steep filters are as linear as shallow ones. Distortion
> can only be added by non-linearity.
>
>>> The bit about sending tiny currents back, creating distortion is
>>> actually technically incorrect too.
>> No it's not, the passive crossovers will shift phase and that IS
>> distortion.
>> ( not that per se active crossovers will overcome that problem, but
>> some do )
>
> Wrong on every count. Phase shift is NOT distortion - it is in fact
> entirely inaudible.

Well it is very easy to prove you are wrong here.
just add two identical sine waves with 180 phase shift,
what will you hear? Hint ... nothing!
So we can talk about how much it is audible but it is clear
that there is an audible effect.


>>> d
>> Edmund
>
> Jolly good.
>
> d

Edmund

[vMike]

"Peter Larsen" > wrote in message
...
> Edmund > wrote:
>
>> vMike wrote:
>
>>> I am thinking of bi amping my speakers using the extra 2 amps on my
>>> 7.1 avr. Using the small v. large settings and adjusting the
>>> crossover, I can adjust the active crossover for the smalls to 350hz
>>> (matching the speakers crossover) so that the mids and tweeters
>>> primarily get upper frequencies. I do not have the ability to adjust
>>> the high pass crossover for the larges so the woofers will get the
>>> full range of frequencies which will then use the speaker's passive
>>> crossover.
>
> Get a proper cross-over then. Behringers DCX may be a candiate PROVIDED
> you are qualified to align the system properly, including getting the line
> levels right for good s-n ratio.
>
>>> Is this limitation going to negate the benefits of biamping?
>
> For a simple answer: that is not what those settings have as purpose. If
> you want to experiment with an active cross-over, then get one.
>
>>> mike
>
>> One of the big advantages in a active system is that the am are direct
>> connected with the drivers. So make sure the amps are direct connected
>> to the drivers without the passive crossover stuff.
>
> I tend to agree that loudspeaker drivers that are connected directly to an
> amplifiers gives the best they can.
>
>> One big mistake often made with active systems is using a very steep
>> crossover just because it can. That isn't going to work very well,
>
> Best active system I have heard yet crossed over at 200 dB pr. octave.
>
>> what you need is a phase correct crossover.
>
> What he needs is a crossover that matches his loudspeakers as system
> consided and matches the requirements for making each and every unit
> perform optimally.
>
>> I don't know what 7.1 avr
>> is
>
> They guy is talking about finagling his el cheapo or somewhat costlio
> surround receiver to use as cross-over. It is plain silly.
>
>> and what woofers you have but if you can wire it as I told you, you
>> be fine.
>
> Allow me to suggest the OP's actual question before typing the answer. If
> there be information lacking, then ask for it up front.
>
>> Edmund
>
> Kind regards
>
> Peter Larsen
>
>
>
I don't think I was talking about finagling anything. I have a pretty
decent system and the speakers sound awesome. I was just thinking that
since I have two extra channels in the system that maybe I should use them
if there was some benefit. I did a little bit of research and it seemed
that if you have active crossovers then there might be a benefit. But I
plan to leave well enough alone.
Mike

[[email protected]]

On Jan 28, 10:43*am, Edmund > wrote:
> Don Pearce wrote:
> > On Wed, 28 Jan 2009 11:18:00 +0100, Edmund >
> >> passive crossovers are pain in many ways, they introduce a LOT
> >> of phase shift in the signal is such a way that the output from
> >> these crossovers alone!! never gives the input signal back.
>
> > Gibberish. They introduce no more phase shift than an active design of
> > similar slope.
>
> That active crossovers have the same phase shift
> doesn't change the fact that that is unwanted.

Nonsense. If my clients present me with a system
with unwanted phase over some band, I'll design
a crossover with just the right amount of complementary
phase to correct it.

Your blanket statement that "phase is unwanted"
is simply wrong.

> Enlish is not mu language

It's not your English I have issue with, it's your
appallingly bad command of physics that's the
problem.

> and I was very unclear with "give the input
> signal back" what I mean is, the sum of the
> output from a crossover with phase shift, is
> never equal to the input signal and there is
> no way to correct that with speaker units.

And you're most assuredly, absolutely 100%
wrong.

> And making a passive filter requires big C's
> and L's, then there is the tolerance of C's
> which makes it hard to get the required values
> end keep values for some time.

I can get 5% tolerance on capacitors of the values
I require: which is better, by not a small amount,
than the tolerances on the drivers they're connected
to.

> these things are much easier to realize with an
> active crossover and as I said, there are no C's
> and L's between the amp and the driver.

Irrelevant.

> * And it doesn't matter what signal they "give back"

Then why bring it up?

> > Wrong on every count. Phase shift is NOT distortion - it is in fact
> > entirely inaudible.
>
> Well it is very easy to prove you are wrong here.
> just add two identical sine waves with 180 phase shift,
> what will you hear? * Hint ... nothing!

Please, spare us the uninformed, childish tricks.
your silly little experiment does NOT demonstrate
anything whatsoever about the audibility of phase.

Try the following experiment: take any speaker, add
2 poles of all-pass filtering at about 500 Hz, and tell
us if you can hear the difference.

> So we can talk about how much it is audible but
> it is clear that there is an audible effect.

Your "demonstration" is absurd on its face.

[Don Pearce[_2_]]

On Wed, 28 Jan 2009 16:43:36 +0100, Edmund >
wrote:

>Don Pearce wrote:
>> On Wed, 28 Jan 2009 11:18:00 +0100, Edmund >
>> wrote:
>>
>>> Don Pearce wrote:
>>>> On Fri, 23 Jan 2009 09:03:32 -0500, "vMike" >
>>>> wrote:
>>>>
>>>>> My understanding of the benefits of bi amp with active crossover (and this
>>>>> may be incorrect) is that the passive crossover in the speaker sends small
>>>>> amounts of current back to the amp through the speaker wires creating a
>>>>> certain amount of distortion. Having active crossover with biamping
>>>>> eliminates much of that distortion whereas having biamping with passive
>>>>> crossover does nothing for that distortion.
>>>>>
>>>>> Any thoughts on that?
>>>>>
>>>> Yes - it is incorrect. I'm not saying that all crossovers are entirely
>>>> free from distortion,
>>> That is one way put it :-)
>>> passive crossovers are pain in many ways, they introduce a LOT
>>> of phase shift in the signal is such a way that the output from
>>> these crossovers alone!! never gives the input signal back.
>>>
>> Gibberish. They introduce no more phase shift than an active design of
>> similar slope.
>
>That active crossovers have the same phase shift doesn't change
>the fact that that is unwanted.
>Enlish is not mu language and I was very unclear with "give the input
>signal back" what I mean is, the sum of the output from a crossover
>with phase shift, is never equal to the input signal and there is no way
>to correct that with speaker units.
>
It does not matter where the crossover is - the effect of phase shift
is identical.

>And making a passive filter requires big C's and L's, then there is the
>tolerance of C's which makes it hard to get the required values end
>keep values for some time.
>these things are much easier to realize with an active crossover and
>as I said, there are no C's and L's between the amp and the driver.
>
>
The loudspeaker crossover has been a done deal for a long time. Inside
the loudspeaker is the right place to put it, because it is a
necessary part of the speaker system. If one were to put it in the
amplifier, one would need a different crossover option for every
speaker the amplifier might need to drive. That is not a sensible
option, particularly given that it would work no better.
>
> And it doesn't matter what signal they "give back"
>> [sic] because the amplifier has such a low output impedance that it is
>> shorted to ground.
>>
>>> An other things is, without a passive network between the amp and
>>> the speaker unit, the amp wil have way better control over the driver.
>>> So that also is way better with active crossover and bi amping.
>>>
>> No it won't. The loss in a passive crossover is low enough that the
>> amplifier maintains full control. The ratio that matters is the
>> crossover resistance to the speaker resistance - more than adequate, I
>> can assure you. And of course when you bi-amp a domestic speaker the
>> crossover is still in circuit - all you do is split the input, so no
>> deal there either.
>>
>>> Then we have the power requirements, one amp driving the entire range
>>> will have to be big enough to drive the bass. When the amp starts to
>>> clip, the passive filters directs these distortion products to the
>>> tweeter and they are very audible! No such thing happens with an active
>>> system. BTW you need LESS power with bi amping too.
>>>
>>
>> Entirely wrong. First off, you don't drive amplifiers into clipping,
>> and if you find you are doing so, you need a bigger amplifier.
>
>well I agree but clipping still happens.
>o,
>> with bi-amping you do not need less power. I have already demonstrated
>> this quite conclusively.
>
>How did you demonstrate that? it isn't true.
>

Look back through the thread - there is a post of mine with the
evidence.

>>
>>>
>>>
>>> but it is all relative. The speaker driver it is
>>>> feeding has distortion levels a hundred times as high.
>>> Steep filters add a lot of distortion too.
>>>
>>
>> No they don't. Steep filters are as linear as shallow ones. Distortion
>> can only be added by non-linearity.
>>
>>>> The bit about sending tiny currents back, creating distortion is
>>>> actually technically incorrect too.
>>> No it's not, the passive crossovers will shift phase and that IS
>>> distortion.
>>> ( not that per se active crossovers will overcome that problem, but
>>> some do )
>>
>> Wrong on every count. Phase shift is NOT distortion - it is in fact
>> entirely inaudible.
>
>Well it is very easy to prove you are wrong here.
>just add two identical sine waves with 180 phase shift,
>what will you hear? Hint ... nothing!
>So we can talk about how much it is audible but it is clear
>that there is an audible effect.
>

What does that have to do with phase shift being audible? Come to
that, what does it have to do with anything?

d

[Peter Larsen[_3_]]

vMike > wrote:

> I don't think I was talking about finagling anything. I have a pretty
> decent system and the speakers sound awesome.

Thank you for clarifying.

> I was just thinking
> that since I have two extra channels in the system that maybe I
> should use them if there was some benefit.

I'd use them for extra loudspeakers.

> I did a little bit of
> research and it seemed that if you have active crossovers then there
> might be a benefit.

That is quite correct.

> But I plan to leave well enough alone.

Paraphrasing something I once read about computers: you can design
loudspeakers or have time to listen to them, but hardly ever both .... it is
possible to get something extraordinary by purchasing quality components and
diy'in it all, but only cheap if a labor of love, if you weigh your own time
at even a single USD pr. hour it gets costly.

> Mike

Kind regards

Peter Larsen

[[email protected]]

On Jan 28, 10:50*am, "vMike" > wrote:
> I don't think I was talking about finagling anything. *

Attempting to convert an existing speaker system to
use an electronic crossover without the measurement
facilities, the design documentation of the original
designer, and without a whole lot of expertise in the
'domain IS finagling.

> I have a pretty decent system and the speakers
> sound awesome.

Then why, on earth, try to fix something that, in
your words, sounds awesome?

>*I was just thinking that since I have two extra
> channels in the system that maybe I should
> use them if there was some benefit.

For existing speaker systems and a small investment
in time, there is not benefit, and real potential to
make things worse, and a fairly high probability
of wasted time.

> But I plan to leave well enough alone.

Excellent idea.

[vMike]

> wrote in message
...
On Jan 28, 10:50 am, "vMike" > wrote:
> I don't think I was talking about finagling anything.

Attempting to convert an existing speaker system to
use an electronic crossover without the measurement
facilities, the design documentation of the original
designer, and without a whole lot of expertise in the
'domain IS finagling.

> I have a pretty decent system and the speakers
> sound awesome.

Then why, on earth, try to fix something that, in
your words, sounds awesome?

> I was just thinking that since I have two extra
> channels in the system that maybe I should
> use them if there was some benefit.

For existing speaker systems and a small investment
in time, there is not benefit, and real potential to
make things worse, and a fairly high probability
of wasted time.

> But I plan to leave well enough alone.

Excellent idea.

Well ... I don't care how awesome anything is ... I never stop trying to
see if it can be better. Whether it is the sound system or the cup of
espresso or you name it.

My guess is there are a few other in the group who are the same.

Thanks for you insights

Mike

[[email protected]]

On Jan 28, 2:28*pm, "vMike" > wrote:
> > wrote in message
>
> ...
> On Jan 28, 10:50 am, "vMike" > wrote:
>
> > I don't think I was talking about finagling anything.
>
> Attempting to convert an existing speaker system to
> use an electronic crossover without the measurement
> facilities, the design documentation of the original
> designer, and without a whole lot of expertise in the
> 'domain IS finagling.
>
> > I have a pretty decent system and the speakers
> > sound awesome.
>
> Then why, on earth, try to fix something that, in
> your words, sounds awesome?
>
> > I was just thinking that since I have two extra
> > channels in the system that maybe I should
> > use them if there was some benefit.
>
> For existing speaker systems and a small investment
> in time, there is not benefit, and real potential to
> make things worse, and a fairly high probability
> of wasted time.
>
> > But I plan to leave well enough alone.
>
> Excellent idea.
>
> Well ... I don't care how awesome anything is ... *I never stop trying to
> see if it can be better. *Whether it is the sound system or the cup of
> espresso or you name it.
>
> My guess is there are a few other in the group who are the same.
>
> Thanks for you insights
>
> Mike

Well if you really want to biamp correctly then you need to pickup a 2
channel active crossover and you will need to open up the speakers and
disconnect parts of the passive crossover in it. If the speakers are
two way you will just have straight connections to the speakers from
each amp. If they are three way you will need to preserve the portion
of the passive crossover that handles the tweeter and midrange
speakers. You will drive both of them with one amp channel and the
woofer with another amp channel. Depending on the passive crossover
design that may be as simple as just disconnecting the woofers from
the crossover. But more complex passive crossovers may require other
changes as well.

It would also be useful to know the original designers intended
crossover points as that would be a good starting point for your
active crossover setting. For many commercial speakers the passive
crossover circuit is fairly simple. The main question will be if the
coils are labeled so that you could reverse the calculations and
determine the intended frequencies. The vast majority of passive
crossovers fall in 3 or 4 basic designs with some minor variations and
possibly some notch filters. All are easily found on the internet.
There may also be documentation on the speakers somewhere around that
gives you the design crossover points without you having to figure it
out. You could also ask the manufacturer.

There is also the much rarer use of tri-amping with 3 way speakers.
But you need 6 channels of amp for that. Then you get a 3 way active
crossover and connect each amp directly to each speaker. No passive
crossover components at all.

The basic premise of biamping is that the larger power swings of the
low frequencies can carry the higher frequencies farther into the
extremes of the amp's total power range. Imagine that a high
frequency sine wave is mixed with a low freqeuncy one that is also a
higher voltage. On a scope you will see the higher frequency "riding"
the lower frequency and the total voltage swing when both waves are in
sync will be the sum of the two. By isolating the low frequency to a
different channel the channel handling the highs is not dealing with
the larger low freqeuncy voltage swings. It also allows you to choose
amps that are more suited to each task. Some people will even run a
tube amp on the high side since one of the big advantages of solid
state amps over tubes is their power handling.

[[email protected]]

On Jan 29, 8:21*am, wrote:

What exactly is it about this topic that causes
so much blither, mythology and technical hooey
to be propagated as TRVTH(tm)?

> Well if you really want to biamp correctly then you need to pickup a 2
> channel active crossover and you will need to open up the speakers and
> disconnect parts of the passive crossover in it. *If the speakers are
> two way you will just have straight connections to the speakers from
> each amp. *If they are three way you will need to preserve the portion
> of the passive crossover that handles the tweeter and midrange
> speakers. *You will drive both of them with one amp channel and the
> woofer with another amp channel. *Depending on the passive crossover
> design that may be as simple as just disconnecting the woofers from
> the crossover. *But more complex passive crossovers may require other
> changes as well.

Almost ALL crossovers in ANY decent speakers will
require this.

PIcming the crossover point and slopes is the
EASY part, and, often the LEAST important part
of the crossover design. NOT A SINGLE ACTIVE
OFF-THE-SHELF CROSSOVER DEALS WITH
THIS.

> It would also be useful to know the original designers intended
> crossover points as that would be a good starting point for your
> active crossover setting.

Again, the crossover points are NOT the problem.
The taoloring of the crossover response to the SYSTEM
is what's the issue, and every one of you go-out-and-
buy-an-active-crossover for reasons I simply don't get
ABSOLUTELY refuses to deal with that issue.

>*For many commercial speakers the passive
> crossover circuit is fairly simple. *The main question will be if the
> coils are labeled so that you could reverse the calculations and
> determine the intended frequencies. *

NO, IT IS NOT. The MAIN question is why do you
think you have more expertise on the design of a
speaker than the designer did?

> The vast majority of passive crossovers fall in 3
> or 4 basic designs with some minor variations and
> possibly some notch filters.

No, they fall into two very distinct categories:
those that work and those that don't. What you're
proposing is a means by which someone can turn
those that work into those that don't in as expensive
a manner as possible.

>*All are easily found on the internet.
> There may also be documentation on the speakers
> somewhere around that gives you the design crossover
> points without you having to figure it
> out.

THE CROSSOVER POINTS AREN'T THE ISSUE.
The design of the crossover and the speaker
TOGETHER as a system IS the issue. And you
propose to basically ignore this piece of physics.

>*You could also ask the manufacturer.

Who will tell you to one degree of politeness or
another to go pound sand.

>*Some people will even run a tube amp on the
> high side since one of the big advantages of solid
> state amps over tubes is their power handling.

And what's the advantage of the tube amp?

In fact, what you're saying in fact is that the
advantage to a high-power amp is that it has
higher power than a low power amp. I'd agree
to that assertion with a hearty "so what?"

[Arny Krueger]

> wrote in message


> Again, the crossover points are NOT the problem.
> The tailoring of the crossover response to the SYSTEM
> is what's the issue, and every one of you go-out-and-
> buy-an-active-crossover for reasons I simply don't get
> ABSOLUTELY refuses to deal with that issue.

How effective are products like the DCX 2496 that implement crossovers by
stringing together various modules?

[[email protected]]

On Jan 29, 8:48*am, wrote:
> On Jan 29, 8:21*am, wrote:
>
> What exactly is it about this topic that causes
> so much blither, mythology and technical hooey
> to be propagated as TRVTH(tm)?
>
> > Well if you really want to biamp correctly then you need to pickup a 2
> > channel active crossover and you will need to open up the speakers and
> > disconnect parts of the passive crossover in it. *If the speakers are
> > two way you will just have straight connections to the speakers from
> > each amp. *If they are three way you will need to preserve the portion
> > of the passive crossover that handles the tweeter and midrange
> > speakers. *You will drive both of them with one amp channel and the
> > woofer with another amp channel. *Depending on the passive crossover
> > design that may be as simple as just disconnecting the woofers from
> > the crossover. *But more complex passive crossovers may require other
> > changes as well.
>
> Almost ALL crossovers in ANY decent speakers will
> require this.
>
> PIcming the crossover point and slopes is the
> EASY part, and, often the LEAST important part
> of the crossover design. NOT A SINGLE ACTIVE
> OFF-THE-SHELF CROSSOVER DEALS WITH
> THIS.
>
> > It would also be useful to know the original designers intended
> > crossover points as that would be a good starting point for your
> > active crossover setting.
>
> Again, the crossover points are NOT the problem.
> The taoloring of the crossover response to the SYSTEM
> is what's the issue, and every one of you go-out-and-
> buy-an-active-crossover for reasons I simply don't get
> ABSOLUTELY refuses to deal with that issue.
>
> >*For many commercial speakers the passive
> > crossover circuit is fairly simple. *The main question will be if the
> > coils are labeled so that you could reverse the calculations and
> > determine the intended frequencies. *
>
> NO, IT IS NOT. The MAIN question is why do you
> think you have more expertise on the design of a
> speaker than the designer did?
>
> > The vast majority of passive crossovers fall in 3
> > or 4 basic designs with some minor variations and
> > possibly some notch filters.
>
> No, they fall into two very distinct categories:
> those that work and those that don't. What you're
> proposing is a means by which someone can turn
> those that work into those that don't in as expensive
> a manner as possible.
>
> >*All are easily found on the internet.
> > There may also be documentation on the speakers
> > somewhere around that gives you the design crossover
> > points without you having to figure it
> > out.
>
> THE CROSSOVER POINTS AREN'T THE ISSUE.
> The design of the crossover and the speaker
> TOGETHER as a system IS the issue. And you
> propose to basically ignore this piece of physics.
>
> >*You could also ask the manufacturer.
>
> Who will tell you to one degree of politeness or
> another to go pound sand.
>
> >*Some people will even run a tube amp on the
> > high side since one of the big advantages of solid
> > state amps over tubes is their power handling.
>
> And what's the advantage of the tube amp?
>
> In fact, what you're saying in fact is that the
> advantage to a high-power amp is that it has
> higher power than a low power amp. I'd agree
> to that assertion with a hearty "so what?"

While the speakers in question are pretty pricy it is my understanding
the factory crossover uses cored inductors and electrolitic
capacitors. A decent active crossover is probably better
technically. Admittedly there may also be notch filters to compensate
for specific cabinet/speaker characteristics that is not so easily
reproduced in the active crossover. It would be interesting to see
the actual schematic of their passive crossover. The sales hype goes
on about "golf ball aerodynamics theory" being used in their port
design which frankly sounds like total tripe. No doubt they might
tell you they have some "revolutionary" new crossover design as well.
Would you believe that?

If I owned those speakers I would very likely not consider trying to
biamp them. Partly for some of the reasons you point out. Does that
constitute agreeing with you? :-)

As to the tube amp, personally I have no use for them. But some do
and one problem is that tube amps can not match the headroom of solid
state amps within anything near similar costs. So the tube amp
afficianado (NOT ME) can have his cake and eat it in terms of headroom
for heart pounding bass while retaining that tube amp sound (what ever
that is, again NOT ME).

[jakdedert]

wrote:
<snip>
>
> If I owned those speakers I would very likely not consider trying to
> biamp them. Partly for some of the reasons you point out. Does that
> constitute agreeing with you? :-)
>
?? Does someone have a link to the OP's speakers. AARC, he id'd them by
a model number (902?) with no brand. Apparently it was something I
'should' know; or he actually listed the brand and I missed it.

This thread is too long to search it out.

jak

[Mr.T]

"Arny Krueger" > wrote in message
...
> How effective are products like the DCX 2496 that implement crossovers by
> stringing together various modules?

IMO any good digital active crossover is highly effective if implemented
properly. Dick is suggesting (probably quite correctly) that most people do
not have the knowledge and test capabilities to do so, not that it can't be
done at all. In fact if starting with a new design from scratch, it is
usually quicker and easier to get a satisfactory result using a programmable
crossover IMO, given the same level of ability and test conditions.

MrT.

[[email protected]]

On Jan 29, 1:40*pm, jakdedert > wrote:
> wrote:
>
> <snip>
>
> > If I owned those speakers I would very likely not consider trying to
> > biamp them. *Partly for some of the reasons you point out. *Does that
> > constitute agreeing with you? :-)
>
> ?? Does someone have a link to the OP's speakers. *AARC, he id'd them by
> a model number (902?) with no brand. *Apparently it was something I
> 'should' know; or he actually listed the brand and I missed it.
>
> This thread is too long to search it out.
>
> jak

I believe he has the B&H 802D's

http://www.avrev.com/home-theater-loudspeakers/floorstanding-loudspeakers/bowers-wilkins-802d-loudpeakers.html

[Arny Krueger]

"Mr.T" <MrT@home> wrote in message

> "Arny Krueger" > wrote in message
> ...

>> How effective are products like the DCX 2496 that
>> implement crossovers by stringing together various
>> modules?

> IMO any good digital active crossover is highly effective
> if implemented properly.

Not necessarily. I've built enough speakers to understand Dick's point.

If you just take say a good Linkwitz-Rielly crossover and hook it up to some
drivers and give it your best shot at adjusting crossover frequencies and
levels, you will probably miss flat response by quite a bit.

This is, if for no other reason, because the transfer functions of the upper
and lower half of crossover which may sum to flat response, also has those
transfer functions multiplied by the transfer functions of the respective
driver. This will yield a different transfer function from the one that sums
so nicely to flat response.

For example, many people hook up two drivers up to a Linkwitz-Reilly (4th
order filters for high and low composed of 2 cascaded second order
Butterworth filters each) crossover and think that they are going to get the
Linkwitz-Reilly's smooth response through the crossover region. Problem is,
adding drivers adds two more filters that may be themselves second order
within an octave or two of the crossover frequency. We now have 3 cascaded
second order filters for each of the upper range and lower range sections of
the speaker speaker. Not exactly what we planned, eh?


> Dick is suggesting (probably
> quite correctly) that most people do not have the
> knowledge and test capabilities to do so, not that it
> can't be done at all.

No, we've found that even if you have the knowledge and the test
capabilities, you won't get adequately flat response with just a good
crossover that lets you adjust crossover frequencies and levels.


> In fact if starting with a new
> design from scratch, it is usually quicker and easier to
> get a satisfactory result using a programmable crossover
> IMO, given the same level of ability and test conditions.

This presumes that the crossover has the necessary other features, beyond
just some complementary filters whose frequency you can adjust, and level
controls.

[Mr.T]

"Arny Krueger" > wrote in message
...
> "Mr.T" <MrT@home> wrote in message
>
> > "Arny Krueger" > wrote in message
> > ...
>
> >> How effective are products like the DCX 2496 that
> >> implement crossovers by stringing together various
> >> modules?
>
> > IMO any good digital active crossover is highly effective
> > if implemented properly.
>
> Not necessarily. I've built enough speakers to understand Dick's point.
>
> If you just take say a good Linkwitz-Rielly crossover and hook it up to
some
> drivers and give it your best shot at adjusting crossover frequencies and
> levels, you will probably miss flat response by quite a bit.

Re-read the "if implemented properly" again.
And the fact that you specifically mentioned a digital programmable
crossover.
But I do admit my "any good digital active crossover" claim does in fact
rely heavily on the definition of "good" :-)


> > Dick is suggesting (probably
> > quite correctly) that most people do not have the
> > knowledge and test capabilities to do so, not that it
> > can't be done at all.
>
> No, we've found that even if you have the knowledge and the test
> capabilities, you won't get adequately flat response with just a good
> crossover that lets you adjust crossover frequencies and levels.

Of course, fortunately we can adjust more than that.
If not then obviously you need a better box :-)

> > In fact if starting with a new
> > design from scratch, it is usually quicker and easier to
> > get a satisfactory result using a programmable crossover
> > IMO, given the same level of ability and test conditions.
>
> This presumes that the crossover has the necessary other features, beyond
> just some complementary filters whose frequency you can adjust, and level
> controls.

Correct.

MrT.

[Kalman Rubinson[_3_]]

On Thu, 29 Jan 2009 11:46:07 -0800 (PST), wrote:

>On Jan 29, 1:40*pm, jakdedert > wrote:
>> wrote:
>>
>> <snip>
>>
>> > If I owned those speakers I would very likely not consider trying to
>> > biamp them. *Partly for some of the reasons you point out. *Does that
>> > constitute agreeing with you? :-)
>>
>> ?? Does someone have a link to the OP's speakers. *AARC, he id'd them by
>> a model number (902?) with no brand. *Apparently it was something I
>> 'should' know; or he actually listed the brand and I missed it.
>>
>> This thread is too long to search it out.
>>
>> jak
>
>I believe he has the B&H 802D's

I went to B&W!

Kal

[Peter Larsen[_3_]]

wrote:

> While the speakers in question are pretty pricy it is my understanding
> the factory crossover uses cored inductors and electrolitic
> capacitors. A decent active crossover is probably better
> technically. Admittedly there may also be notch filters to compensate
> for specific cabinet/speaker characteristics that is not so easily
> reproduced in the active crossover. It would be interesting to see
> the actual schematic of their passive crossover. The sales hype goes
> on about "golf ball aerodynamics theory" being used in their port
> design which frankly sounds like total tripe.

Nah, there is a good sporting chance that it at least sounds less.

Kind regards

Peter Larsen

[Mr.T]

> wrote:
>
> While the speakers in question are pretty pricy it is my understanding
> the factory crossover uses cored inductors and electrolitic
> capacitors. A decent active crossover is probably better
> technically. Admittedly there may also be notch filters to compensate
> for specific cabinet/speaker characteristics that is not so easily
> reproduced in the active crossover.

I have to wonder what filters are "not so easily" implemented in a fully
programmable digital active crossover these days?
I think the only real limitation would be the firmware/software or the
programmer.

MrT.

[[email protected]]

On Jan 29, 11:58*am, wrote:
> On Jan 29, 8:48*am, wrote:
> > THE CROSSOVER POINTS AREN'T THE ISSUE.
> > The design of the crossover and the speaker
> > TOGETHER as a system IS the issue. And you
> > propose to basically ignore this piece of physics.
>
> While the speakers in question are pretty pricy it
> is my understanding the factory crossover uses
> cored inductors and electrolitic capacitors.

How is that at all relevant?

>*A decent active crossover is probably better
> technically. *

Not if it is not explicitly designed to be integrated
in to the system, it isn't.

Is there any reason why you are insisting on
ognoring this very crucial point? How is the issue
of "cored inductors" in any way relevant? I'd
much rather have a passice crossover with cored
inductors that gets me the right response than the
best active generic active crossover in the world.

> Admittedly there may also be notch filters to
> compensate for specific cabinet/speaker
> characteristics that is not so easily
> reproduced in the active crossover. *

Well, thank you for your mild "admission," but
it's something that has been well known and well
understood by any number of competent speaker
designers for decades, and you just getting around
to "admitting" it?

Your admission suggests, then, that off-the-shelf
active crossover are likely NOT to be better than
the purpose designed passice networks in a
competently designed speaker SYSTEM, eh?

> It would be interesting to see the actual
> schematic of their passive crossover. *

Which in and of itslef would tell you relatively
little. without ALL the design criteria and factors
that went into the SYSTEM design, you're not
going to understand the SYSTEM.

> The sales hype goes on about "golf ball
> aerodynamics theory" being used in their port
> design which frankly sounds like total tripe. *

No, because right surface profile is capable of
substantially alleviating effects due to boundary-
layer turbulence.

> No doubt they might tell you they have some
> "revolutionary" new crossover design as well.

"No doubt" and "they might" seems a bit contradictory.

> Would you believe that?

Would I believe what?

[[email protected]]

On Jan 29, 6:03*pm, wrote:
> On Jan 29, 11:58*am, wrote:
>
> > On Jan 29, 8:48*am, wrote:
> > > THE CROSSOVER POINTS AREN'T THE ISSUE.
> > > The design of the crossover and the speaker
> > > TOGETHER as a system IS the issue. And you
> > > propose to basically ignore this piece of physics.
>
> > While the speakers in question are pretty pricy it
> > is my understanding the factory crossover uses
> > cored inductors and electrolitic capacitors.
>
> How is that at all relevant?
>
> >*A decent active crossover is probably better
> > technically. *
>
> Not if it is not explicitly designed to be integrated
> in to the system, it isn't.
>
> Is there any reason why you are insisting on
> ognoring this very crucial point? How is the issue
> of "cored inductors" in any way relevant? I'd
> much rather have a passice crossover with cored
> inductors that gets me the right response than the
> best active generic active crossover in the world.
>
> > Admittedly there may also be notch filters to
> > compensate for specific cabinet/speaker
> > characteristics that is not so easily
> > reproduced in the active crossover. *
>
> Well, thank you for your mild "admission," but
> it's something that has been well known and well
> understood by any number of competent speaker
> designers for decades, and you just getting around
> to "admitting" it?
>
> Your admission suggests, then, that off-the-shelf
> active crossover are likely NOT to be better than
> the purpose designed passice networks in a
> competently designed speaker SYSTEM, eh?
>
> > It would be interesting to see the actual
> > schematic of their passive crossover. *
>
> Which in and of itslef would tell you relatively
> little. without ALL the design criteria and factors
> that went into the SYSTEM design, you're not
> going to understand the SYSTEM.
>
> > The sales hype goes on about "golf ball
> > aerodynamics theory" being used in their port
> > design which frankly sounds like total tripe. *
>
> No, because right surface profile is capable of
> substantially alleviating effects due to boundary-
> layer turbulence.
>
> > No doubt they might tell you they have some
> > "revolutionary" new crossover design as well.
>
> "No doubt" and "they might" seems a bit contradictory.
>
> > Would you believe that?
>
> Would I believe what?

Ferrite core and electrolitics are generally accepted to be inferior
to air core and polypropylene for use in crossovers. They certainly
are cheaper. Cheaper is not what I expect to find when I look under
the "hood" of speakers in that price range. And the best solution for
port turbulence is no port. That they used "theory" when designing
their port suggests that they didn't really test anything, they just
think that the theory is applicable. You think they tested?

Without a schematic of their crossover we are just speculating as to
how it compares to a standard active crossover. For all you know it's
a vanilla 12 db circuit. In this price range I would expect more but
I also expected air core and polypropylene as well and I was wrong
there.

[Serge Auckland[_2_]]

> wrote in message
...
On Jan 29, 11:58 am, wrote:
> On Jan 29, 8:48 am, wrote:
> > THE CROSSOVER POINTS AREN'T THE ISSUE.
> > The design of the crossover and the speaker
> > TOGETHER as a system IS the issue. And you
> > propose to basically ignore this piece of physics.
>


Dick,

I've seen a number of so-called "audiophile" loudspeakers that have very
simple crossovers, some as simple as a single capacitor, but many which
consist of simple LC sections, with perhaps a single resistor to reduce
tweeter levels. Many such manufacturers make a virtue of their simple
crossover design. Now I know this is all marketing, they make a virtue of
their limitations, but is there any reason that someone with one of these
loudspeakers couldn't use a DSP-based electronic crossover?

I ask also because a project I have in mind for the future is to change the
crossover in the Tannoy 15" Dual Concentric for an electronic one. Looking
at the circuit diagram of Tannoy's crossover looks like something that could
be replicated with an electronic device. Am I missing something?

Best regards

S.
--
http://audiopages.googlepages.com

[Peter Larsen[_3_]]

wrote:

> Ferrite core and electrolitics are generally accepted to be inferior
> to air core and polypropylene for use in crossovers.

I am open to the issue of component sound, however there is an issue an
order of magnitude larger, the one of getting a decent frequency response.
One of the great "extras" of computer optimisation is that it is easy to
factor cross-over component properties into the cross-over, and if that is
done then it gets to be a very poor idea to replace the actual coil, cored
or not.

> They certainly are cheaper. Cheaper is not what I expect to
> find when I look under the "hood" of speakers in that price range.

There was some mentioning of the OP's speakers being B&W's. There are a few
tweaks that I want to undertake when listening to some B&W's, but not of
their cross-over based on what I have ascertained at demonstrations of them,
ie. sub-optimal listening conditions. Generally they are very good at
highlighting what is wrong about whatever is in front of them .... programme
included.

On the note of subtleties ... once you have tried making some recordings and
experienced the influence on the sound of an instrument of moving it one
meter in the room, or of opening the lid of the nearby piano, then you get a
different attitude to what matters. These changes in sound are gross. The
changes in amount of information perceived by ""upgrading"" cross-over
components is nowhere near those differences. In my opinion the way to real
transparency is not to "upgrade" a crossover, but to replace it with a
digital optimized solution if passive is not good enough. That said, I did
pay for an upgrade of my L100's and it was worth it (a required slope was
not implemented ex works in the actual version) ... but the state of the art
of "cross-overing" is somewhat higher in whatever comes out of B&W'w plant.

> And the best solution for port turbulence is no port.

Yes. But the cost is higher distortion in the bass range.

> That they used "theory" when designing
> their port suggests that they didn't really test anything, they just
> think that the theory is applicable. You think they tested?

The minor gripe I occasionally have had with B&W is that they measured too
much and listened too little on the first models after the DM2A. From a
measuring and theory viewpoint a slightly silly construction, but one that
provided excellent listenability.

> Without a schematic of their crossover we are just speculating as to
> how it compares to a standard active crossover. For all you know it's
> a vanilla 12 db circuit.

First you say that you know nothing and then that you know exactly what it
is. You don't. You only know that after measuring the actual output from the
units.

> In this price range I would expect more but
> I also expected air core and polypropylene as well and I was wrong
> there.

I don't know the actual loudspeaker, nor its price range and I haven't
listened. I like to use air core and polypropylene in my diy, but I also
know just how much an increase in the component cost hits the over the
counter price and the slight quality increase is not likely to match that.
Do no mess with the coils, their actual properties is likely to constitute A
cross-over component that you overlook. In fact, with a modern, computer
optimized, design, do not at all mess with it at all unless you have
facilities similar to those of the manufacturer.

Kind regards

Peter Larsen

[[email protected]]

On Jan 30, 8:35*am, "Serge Auckland" >
wrote:
> > wrote in message
>
> ...
> On Jan 29, 11:58 am, wrote:
>
> > On Jan 29, 8:48 am, wrote:
> > > THE CROSSOVER POINTS AREN'T THE ISSUE.
> > > The design of the crossover and the speaker
> > > TOGETHER as a system IS the issue. And you
> > > propose to basically ignore this piece of physics.
>
> Dick,
>
> I've seen a number of so-called "audiophile" loudspeakers that have very
> simple crossovers, some as simple as a single capacitor, but many which
> consist of simple LC sections, with perhaps a single resistor to reduce
> tweeter levels. Many such manufacturers make a virtue of their simple
> crossover design. Now I know this is all marketing, they make a virtue of
> their limitations, but is there any reason that someone with one of these
> loudspeakers couldn't use a DSP-based electronic crossover?
>
> I ask also because a project I have in mind for the future is to change the
> crossover in the Tannoy 15" Dual Concentric for an electronic one. Looking
> at the circuit diagram of Tannoy's crossover looks like something that could
> be replicated with an electronic device. Am I missing something?
>
> Best regards
>
> S.
> --http://audiopages.googlepages.com

He's assuming that the crossover in question has additional components
beyond one of the common crossover designs. Such as additional
filters to compensate for peaks or fall off somewhere. A point I say
is just theoretical until we see the schematic of the crossover in
question. An active crossover is an acceptable substitution for a
basic no frills passive crossover. It is essentially the same thing
substituted further up the signal path. If you wish to experiment,
it's far easier than changing passive components at the output stage.
And if you really want to you can get active equipment that will also
let you introduce and adjust other filtering effects as well.

True, there is a school of thought that additional complexity in the
crossover just introduces as many problems as it creates. As you know
the speaker is not a straight load, it has inductive properties as
well. Some would point out capacitive too. And the load the cabinet
places on the speaker has yet another impact. Of course all this
varying with frequency. While the complete behavior is pretty easy to
observe at one frequency it's a whole nother beast to determine what
the total effects of the speaker, cabinet, and crossover components
are on that vastly more complex music signal. Never mind measuring
the effects of port design on turbulence. Imho all that's what's
behind the simple is better school. Some of the same proponents of
biamping also recommend simple no frills 6 db or 12 db crossovers from
the mid/tweeter section. There are a number of camps and they all
have their pluses and minuses. Some people would point out that all
the complicated reflections in the typical home listening room negate
the bulk of this fine tweaking anyway.

[GregS[_3_]]

In article >, wrote:
>On Jan 30, 8:35=A0am, "Serge Auckland" >
>wrote:
>> > wrote in message
>>
>> ...
>> On Jan 29, 11:58 am, wrote:
>>
>> > On Jan 29, 8:48 am, wrote:
>> > > THE CROSSOVER POINTS AREN'T THE ISSUE.
>> > > The design of the crossover and the speaker
>> > > TOGETHER as a system IS the issue. And you
>> > > propose to basically ignore this piece of physics.
>>
>> Dick,
>>
>> I've seen a number of so-called "audiophile" loudspeakers that have very
>> simple crossovers, some as simple as a single capacitor, but many which
>> consist of simple LC sections, with perhaps a single resistor to reduce
>> tweeter levels. Many such manufacturers make a virtue of their simple
>> crossover design. Now I know this is all marketing, they make a virtue of
>> their limitations, but is there any reason that someone with one of these
>> loudspeakers couldn't use a DSP-based electronic crossover?
>>
>> I ask also because a project I have in mind for the future is to change t=
>he
>> crossover in the Tannoy 15" Dual Concentric for an electronic one. Lookin=
>g
>> at the circuit diagram of Tannoy's crossover looks like something that co=
>uld
>> be replicated with an electronic device. Am I missing something?

I think you have to consider the crossover-driver interaction. If you duplicated passive
with active, the driver does not see the same thing. It sees the amplifier output.
You have to duplicated the whole action of the passive crossover in the active crossover.

greg


>> Best regards
>>
>> S.
>> --http://audiopages.googlepages.com
>
>He's assuming that the crossover in question has additional components
>beyond one of the common crossover designs. Such as additional
>filters to compensate for peaks or fall off somewhere. A point I say
>is just theoretical until we see the schematic of the crossover in
>question. An active crossover is an acceptable substitution for a
>basic no frills passive crossover. It is essentially the same thing
>substituted further up the signal path. If you wish to experiment,
>it's far easier than changing passive components at the output stage.
>And if you really want to you can get active equipment that will also
>let you introduce and adjust other filtering effects as well.
>
>True, there is a school of thought that additional complexity in the
>crossover just introduces as many problems as it creates. As you know
>the speaker is not a straight load, it has inductive properties as
>well. Some would point out capacitive too. And the load the cabinet
>places on the speaker has yet another impact. Of course all this
>varying with frequency. While the complete behavior is pretty easy to
>observe at one frequency it's a whole nother beast to determine what
>the total effects of the speaker, cabinet, and crossover components
>are on that vastly more complex music signal. Never mind measuring
>the effects of port design on turbulence. Imho all that's what's
>behind the simple is better school. Some of the same proponents of
>biamping also recommend simple no frills 6 db or 12 db crossovers from
>the mid/tweeter section. There are a number of camps and they all
>have their pluses and minuses. Some people would point out that all
>the complicated reflections in the typical home listening room negate
>the bulk of this fine tweaking anyway.

[[email protected]]

On Jan 30, 11:14*am, (GregS) wrote:
> In article >, wrote:
>
>
>
>
>
> >On Jan 30, 8:35=A0am, "Serge Auckland" >
> >wrote:
> >> > wrote in message
>
> ....
> >> On Jan 29, 11:58 am, wrote:
>
> >> > On Jan 29, 8:48 am, wrote:
> >> > > THE CROSSOVER POINTS AREN'T THE ISSUE.
> >> > > The design of the crossover and the speaker
> >> > > TOGETHER as a system IS the issue. And you
> >> > > propose to basically ignore this piece of physics.
>
> >> Dick,
>
> >> I've seen a number of so-called "audiophile" loudspeakers that have very
> >> simple crossovers, some as simple as a single capacitor, but many which
> >> consist of simple LC sections, with perhaps a single resistor to reduce
> >> tweeter levels. Many such manufacturers make a virtue of their simple
> >> crossover design. Now I know this is all marketing, they make a virtue of
> >> their limitations, but is there any reason that someone with one of these
> >> loudspeakers couldn't use a DSP-based electronic crossover?
>
> >> I ask also because a project I have in mind for the future is to change t=
> >he
> >> crossover in the Tannoy 15" Dual Concentric for an electronic one. Lookin=
> >g
> >> at the circuit diagram of Tannoy's crossover looks like something that co=
> >uld
> >> be replicated with an electronic device. Am I missing something?
>
> I think you have to consider the crossover-driver interaction. If you duplicated passive
> with active, the driver does not see the same thing. It sees the amplifier output.
> You have to duplicated the whole action of the passive crossover in the active crossover.
>
> greg
>
>
>
> >> Best regards
>
> >> S.
> >> --http://audiopages.googlepages.com
>
> >He's assuming that the crossover in question has additional components
> >beyond one of the common crossover designs. *Such as additional
> >filters to compensate for peaks or fall off somewhere. *A point I say
> >is just theoretical until we see the schematic of the crossover in
> >question. *An active crossover is an acceptable substitution for a
> >basic no frills passive crossover. *It is essentially the same thing
> >substituted further up the signal path. *If you wish to experiment,
> >it's far easier than changing passive components at the output stage.
> >And if you really want to you can get active equipment that will also
> >let you introduce and adjust other filtering effects as well.
>
> >True, there is a school of thought that additional complexity in the
> >crossover just introduces as many problems as it creates. *As you know
> >the speaker is not a straight load, it has inductive properties as
> >well. *Some would point out capacitive too. *And the load the cabinet
> >places on the speaker has yet another impact. *Of course all this
> >varying with frequency. *While the complete behavior is pretty easy to
> >observe at one frequency it's a whole nother beast to determine what
> >the total effects of the speaker, cabinet, and crossover components
> >are on that vastly more complex music signal. *Never mind measuring
> >the effects of port design on turbulence. *Imho all that's what's
> >behind the simple is better school. *Some of the same proponents of
> >biamping also recommend simple no frills 6 db or 12 db crossovers from
> >the mid/tweeter section. *There are a number of camps and they all
> >have their pluses and minuses. *Some people would point out that all
> >the complicated reflections in the typical home listening room negate
> >the bulk of this fine tweaking anyway.- Hide quoted text -
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -

Legitimate point.

[vMike]

> wrote in message
...
On Jan 29, 1:40 pm, jakdedert > wrote:
> wrote:
>
> <snip>
>
> > If I owned those speakers I would very likely not consider trying to
> > biamp them. Partly for some of the reasons you point out. Does that
> > constitute agreeing with you? :-)
>
> ?? Does someone have a link to the OP's speakers. AARC, he id'd them by
> a model number (902?) with no brand. Apparently it was something I
> 'should' know; or he actually listed the brand and I missed it.
>
> This thread is too long to search it out.
>
> jak

I believe he has the B&H 802D's

http://www.avrev.com/home-theater-loudspeakers/floorstanding-loudspeakers/bowers-wilkins-802d-loudpeakers.html

Yes they are B&W 802D's
mike

[[email protected]]

On Jan 30, 8:21*am, wrote:
> Ferrite core and electrolitics are generally accepted to be inferior
> to air core and polypropylene for use in crossovers. *

Spare me the "generally accepted" nonsense.

It's "generally acceped" that active crossovers are
better than passive crossovers. It's "generally accepted"
that CD output has stair-step waveforms. It's "generally
accepted" that LPs have infinite resolution. It's "generally
accepted" that digital audio can't resolve time events
less than a single sample period.

It's "generally accepted" is a cover for grotesque stupidity
and laziness in the audio world.

> They certainly
> are cheaper. *Cheaper is not what I expect to find when
> I look under the "hood" of speakers in that price range. *

That's because you are in no position to make
that sort of judgement. Loudspeaker design of ALL
kinds is primarily a balance of competing priorities,
a very important one is cost. The money saved on
the difference between two different kinds of cap or
coil is actually a very SMALL part of the total parts
budget of most loudspeakers. The cabinet, the drivers,
non-direct labor costs, dealer profi are all much larger.
A typical speaker in the specialty (non-mass market)
audio business will have, at most 20-25% of its retail
price tied up in direct materials cost. Of that, 80% is
cabinet and drivers. That leaves EVERYTHING ELSE,
like sipping carton, the TOTAL crossover, and so on,
taking up, at most, 5% of the total retail cost. changing
from a $2 coil to a $4 coil might add on the order of
$20 to the total retail price of a loudspeaker.

It's NOT a cost issue and to claim so or get upset
exposes a great deal of naivety about how the
loudspeaker business HAS to work.

> And the best solution for port turbulence is no port.

Bullsh*t, in a word. Look, you're ding a superb job
of revealing to the assembled crowd how little you
know. Id recommend stopping while you're still slightly
ahead.

Vented design provides a number of very valuable design
advantages to a competent designer. That there are
incompetent designers and, more importantly, arm-
chair commentators who are clueless about such matters,
but fortunately none of them stand in the way of
competent designs.

To quote and old sage, "any idiot can design a
loudspeaker and, regrettably, many do." It's correlary
is "any idot can have an opinion about stuff he doesn't
know about, and, regrettably, many do."

>*That they used "theory" when designing
> their port suggests that they didn't really
> test anything, they just think that the theory
> is applicable. *

It suggests nothing of the sort.

> You think they tested?

You have anything otherv than your uninformed opinion
they did not?

> Without a schematic of their crossover we are just
> speculating as to how it compares to a standard
> active crossover. *

I would kindly suggest that you refain from the use of
"we" here, because "you" really have no idea. I, on the
other hand, have spent the last 35 years designing
and measuring this stuff, and have, in fact, measured
thousands of examples of such.

> For all you know it's a vanilla 12 db circuit. *

If it's B&W we are talking about, I'll bet you $1000
and give you 4:1 odds is it not.

You want to take the bet?

> In this price range I would expect more but
> I also expected air core and polypropylene
> as well and I was wrong there.

That's because your expectations are a result
of lack of information, expertise and not a small
amount of ill-formed preconceived notions.

Unless you have something other than amateurish
handwaving, I'm done.

[Peter Larsen[_3_]]

Serge Auckland > wrote:

> I ask also because a project I have in mind for the future is to
> change the crossover in the Tannoy 15" Dual Concentric for an
> electronic one.

Hmmm ... did that with a pair of 12" once upon a time.

> Looking at the circuit diagram of Tannoy's crossover
> looks like something that could be replicated with an electronic
> device. Am I missing something?

That HF horn is quite close to being an image of Matterhorn, ie. with a peak
at 4 kHz and a first order slope on either side. Try to find a pair of Coral
H100's for use above some 8 kHz and be very happy, that was what I ended up
with doing in 1978. And with a fairly simple passive cross-over, in theory I
still have the diagram and may be able to scan it and put it on my site. A
Technics parametric (the 17" one, sold it and still miss it, very practical)
was a required addition to the system.

What made me revert to passive was the sn-issue, the Luxman MQ80 valve amp I
had purchased to drive the horns was too darn noisy. The Sansui B55 is a
great amp for driving compression drivers, but you need to physically remove
the spectrum analyzer and replacing the coupling cap in the input with a
suitable magnitude polypropylene is advisable.

Be careful with the ex works cross-over boxes, contents are under pressure
due to all the fine detail that has been trapped in them.

> Best regards

> S.

Kind regards

Peter Larsen

[[email protected]]

On Jan 30, 11:01*am, wrote:
> On Jan 30, 8:35*am, "Serge Auckland" >
> wrote:
> > > wrote in message
> > > > THE CROSSOVER POINTS AREN'T THE ISSUE.
> > > > The design of the crossover and the speaker
> > > > TOGETHER as a system IS the issue. And you
> > > > propose to basically ignore this piece of physics.
>
> > Dick,
>
> > I've seen a number of so-called "audiophile" loudspeakers that have very
> > simple crossovers, some as simple as a single capacitor, but many which
> > consist of simple LC sections, with perhaps a single resistor to reduce
> > tweeter levels. Many such manufacturers make a virtue of their simple
> > crossover design. Now I know this is all marketing, they make a virtue of
> > their limitations, but is there any reason that someone with one of these
> > loudspeakers couldn't use a DSP-based electronic crossover?
>
> He's assuming that the crossover in question has
> additional components beyond one of the common
> crossover designs. *Such as additional filters to
> compensate for peaks or fall off somewhere. *

I am making NO such assumption, and I would kindly
ask that you not assume that everyone works from the
same base of information that you do.

Take for example, the issue of a driver that has a rising
response. Taking a conventional 2-pol filter and staggering
the poles to result in an overdamped response in the
network is one way of dealing with that.

> A point I say is just theoretical until we see the
> schematic of the crossover in question. *

And without the entrie system information in
hand, a schematic is not going to tell anyone,
especially you, what's going on, because you have
already formed an opinion, unencumbered by fact,
as to what's going on.

> An active crossover is an acceptable substitution for a
> basic no frills passive crossover. *

That would be another one of those uninformed
opinions.

> True, there is a school of thought that additional
> complexity in the crossover just introduces as
> many problems as it creates. *

That's the same "generally accepted" school of thought
you graduated from?

> As you know
> the speaker is not a straight load, it has inductive properties as
> well. *

Yes, those of us that actually do work in this realm are
well aware of the properties AND well aware of how to
effectively deal with them.

> Some would point out capacitive too. *

And so far, all the people you are referring to would
be wrong.

A woofer exhibits alternatively resistive, inductive,
resistive, capacitive, resistive and inductive components
to its impedance as we move up in frequency. But at
NO place is the impedance every anything other than
predominantly are largely resistive.

> *Imho all that's what's behind the simple is better
> school.

And that's another opinion. Physics has a way of ignoring
opinion, especially the uninformed variety.

>*Some of the same proponents of biamping also
> recommend simple no frills 6 db or 12 db crossovers from
> the mid/tweeter section. *

So what?

> There are a number of camps and they all
> have their pluses and minuses. *

And some are just plain wrong.

[[email protected]]

On Jan 30, 11:55*am, wrote:
> On Jan 30, 11:01*am, wrote:
>
>
>
>
>
> > On Jan 30, 8:35*am, "Serge Auckland" >
> > wrote:
> > > > wrote in message
> > > > > THE CROSSOVER POINTS AREN'T THE ISSUE.
> > > > > The design of the crossover and the speaker
> > > > > TOGETHER as a system IS the issue. And you
> > > > > propose to basically ignore this piece of physics.
>
> > > Dick,
>
> > > I've seen a number of so-called "audiophile" loudspeakers that have very
> > > simple crossovers, some as simple as a single capacitor, but many which
> > > consist of simple LC sections, with perhaps a single resistor to reduce
> > > tweeter levels. Many such manufacturers make a virtue of their simple
> > > crossover design. Now I know this is all marketing, they make a virtue of
> > > their limitations, but is there any reason that someone with one of these
> > > loudspeakers couldn't use a DSP-based electronic crossover?
>
> > He's assuming that the crossover in question has
> > additional components beyond one of the common
> > crossover designs. *Such as additional filters to
> > compensate for peaks or fall off somewhere. *
>
> I am making NO such assumption, and I would kindly
> ask that you not assume that everyone works from the
> same base of information that you do.
>
> Take for example, the issue of a driver that has a rising
> response. Taking a conventional 2-pol filter and staggering
> the poles to result in an overdamped response in the
> network is one way of dealing with that.
>
> > A point I say is just theoretical until we see the
> > schematic of the crossover in question. *
>
> And without the entrie system information in
> hand, a schematic is not going to tell anyone,
> especially you, what's going on, because you have
> already formed an opinion, unencumbered by fact,
> as to what's going on.
>
> > An active crossover is an acceptable substitution for a
> > basic no frills passive crossover. *
>
> That would be another one of those uninformed
> opinions.
>
> > True, there is a school of thought that additional
> > complexity in the crossover just introduces as
> > many problems as it creates. *
>
> That's the same "generally accepted" school of thought
> you graduated from?
>
> > As you know
> > the speaker is not a straight load, it has inductive properties as
> > well. *
>
> Yes, those of us that actually do work in this realm are
> well aware of the properties AND well aware of how to
> effectively deal with them.
>
> > Some would point out capacitive too. *
>
> And so far, all the people you are referring to would
> be wrong.
>
> A woofer exhibits alternatively resistive, inductive,
> resistive, capacitive, resistive and inductive components
> to its impedance as we move up in frequency. But at
> NO place is the impedance every anything other than
> predominantly are largely resistive.
>
> > *Imho all that's what's behind the simple is better
> > school.
>
> And that's another opinion. Physics has a way of ignoring
> opinion, especially the uninformed variety.
>
> >*Some of the same proponents of biamping also
> > recommend simple no frills 6 db or 12 db crossovers from
> > the mid/tweeter section. *
>
> So what?
>
> > There are a number of camps and they all
> > have their pluses and minuses. *
>
> And some are just plain wrong.- Hide quoted text -
>
> - Show quoted text -

You have some valid points. But if you would tone down the rant level
some you would probably get them across better. Since you take the
time to post I have to think that is your goal.

> > Some would point out capacitive too.
>
> And so far, all the people you are referring to would
> be wrong.
>
> A woofer exhibits alternatively resistive, inductive,
> resistive, capacitive, resistive and inductive components
> to its impedance as we move up in frequency. But at
> NO place is the impedance every anything other than
> predominantly are largely resistive.

Here you claim something to be wrong and yet in the next paragraph
make the same statement. No where did I claim that any of these other
characteristics exceed the resistive load. I have to guess that is
the point of your second sentence though it is difficult to tell from
the poor wording. Are you saying that the only characteristic of the
speaker that matters is the resistive load?

[jakdedert]

vMike wrote:
> > wrote in message
> ...
> On Jan 29, 1:40 pm, jakdedert > wrote:
>> wrote:
>>
>> <snip>
>>
>>> If I owned those speakers I would very likely not consider trying to
>>> biamp them. Partly for some of the reasons you point out. Does that
>>> constitute agreeing with you? :-)
>> ?? Does someone have a link to the OP's speakers. AARC, he id'd them by
>> a model number (902?) with no brand. Apparently it was something I
>> 'should' know; or he actually listed the brand and I missed it.
>>
>> This thread is too long to search it out.
>>
>> jak
>
> I believe he has the B&H 802D's
>
> http://www.avrev.com/home-theater-loudspeakers/floorstanding-loudspeakers/bowers-wilkins-802d-loudpeakers.html
>
> Yes they are B&W 802D's
> mike
>
>
Okay, now I'm stumped. He's got $12,000 speakers and wanted to hack
into them and DIY a crossover. Some people....

jak

[[email protected]]

On Jan 30, 12:46*pm, jakdedert > wrote:
> vMike wrote:
> > > wrote in message
> ...
> > On Jan 29, 1:40 pm, jakdedert > wrote:
> >> wrote:
>
> >> <snip>
>
> >>> If I owned those speakers I would very likely not consider trying to
> >>> biamp them. Partly for some of the reasons you point out. Does that
> >>> constitute agreeing with you? :-)
> >> ?? Does someone have a link to the OP's speakers. AARC, he id'd them by
> >> a model number (902?) with no brand. Apparently it was something I
> >> 'should' know; or he actually listed the brand and I missed it.
>
> >> This thread is too long to search it out.
>
> >> jak
>
> > I believe he has the B&H 802D's
>
> >http://www.avrev.com/home-theater-loudspeakers/floorstanding-loudspea...
>
> > Yes they are B&W 802D's
> > mike
>
> Okay, now I'm stumped. *He's got $12,000 speakers and wanted to hack
> into them and DIY a crossover. *Some people....
>
> jak- Hide quoted text -
>
> - Show quoted text -

Agreed, but I think he has already on board with the leave them alone
idea.

[vMike]

"jakdedert" > wrote in message
...
> vMike wrote:
>> > wrote in message
>> ...
>> On Jan 29, 1:40 pm, jakdedert > wrote:
>>> wrote:
>>>
>>> <snip>
>>>
>>>> If I owned those speakers I would very likely not consider trying to
>>>> biamp them. Partly for some of the reasons you point out. Does that
>>>> constitute agreeing with you? :-)
>>> ?? Does someone have a link to the OP's speakers. AARC, he id'd them by
>>> a model number (902?) with no brand. Apparently it was something I
>>> 'should' know; or he actually listed the brand and I missed it.
>>>
>>> This thread is too long to search it out.
>>>
>>> jak
>>
>> I believe he has the B&H 802D's
>>
>> http://www.avrev.com/home-theater-loudspeakers/floorstanding-loudspeakers/bowers-wilkins-802d-loudpeakers.html
>>
>> Yes they are B&W 802D's
>> mike
>>
>>
> Okay, now I'm stumped. He's got $12,000 speakers and wanted to hack into
> them and DIY a crossover. Some people....
>
> jak

I never intended to hack anything apart. No way
Mike

[vMike]

"vMike" > wrote in message
...
>
> "jakdedert" > wrote in message
> ...
>> vMike wrote:
>>> > wrote in message
>>> ...
>>> On Jan 29, 1:40 pm, jakdedert > wrote:
>>>> wrote:
>>>>
>>>> <snip>
>>>>
>>>>> If I owned those speakers I would very likely not consider trying to
>>>>> biamp them. Partly for some of the reasons you point out. Does that
>>>>> constitute agreeing with you? :-)
>>>> ?? Does someone have a link to the OP's speakers. AARC, he id'd them by
>>>> a model number (902?) with no brand. Apparently it was something I
>>>> 'should' know; or he actually listed the brand and I missed it.
>>>>
>>>> This thread is too long to search it out.
>>>>
>>>> jak
>>>
>>> I believe he has the B&H 802D's
>>>
>>> http://www.avrev.com/home-theater-loudspeakers/floorstanding-loudspeakers/bowers-wilkins-802d-loudpeakers.html
>>>
>>> Yes they are B&W 802D's
>>> mike
>>>
>>>
>> Okay, now I'm stumped. He's got $12,000 speakers and wanted to hack into
>> them and DIY a crossover. Some people....
>>
>> jak
>
> I never intended to hack anything apart. No way
> Mike
>
>
I simply was considering plugging one amp feed into the upper terminals and
one into the bottom, and use the amps where I could to adjust the crossover
to the speakers. That was it. I didn't realize I would start such a
debate, but it is nice to read some of the opinions.

Mike

[vMike]

> wrote in message
...
On Jan 30, 12:46 pm, jakdedert > wrote:
> vMike wrote:
> > > wrote in message
> ...
> > On Jan 29, 1:40 pm, jakdedert > wrote:
> >> wrote:
>
> >> <snip>
>
> >>> If I owned those speakers I would very likely not consider trying to
> >>> biamp them. Partly for some of the reasons you point out. Does that
> >>> constitute agreeing with you? :-)
> >> ?? Does someone have a link to the OP's speakers. AARC, he id'd them by
> >> a model number (902?) with no brand. Apparently it was something I
> >> 'should' know; or he actually listed the brand and I missed it.
>
> >> This thread is too long to search it out.
>
> >> jak
>
> > I believe he has the B&H 802D's
>
> >http://www.avrev.com/home-theater-loudspeakers/floorstanding-loudspea...


Plus the place I bought the speakers from was trying to sell me 4 Classe
amps.

mike

[[email protected]]

On Jan 30, 1:11*pm, "vMike" > wrote:
> > wrote in message
>
> ...
> On Jan 30, 12:46 pm, jakdedert > wrote:
>
>
>
>
>
> > vMike wrote:
> > > > wrote in message
> > ....
> > > On Jan 29, 1:40 pm, jakdedert > wrote:
> > >> wrote:
>
> > >> <snip>
>
> > >>> If I owned those speakers I would very likely not consider trying to
> > >>> biamp them. Partly for some of the reasons you point out. Does that
> > >>> constitute agreeing with you? :-)
> > >> ?? Does someone have a link to the OP's speakers. AARC, he id'd them by
> > >> a model number (902?) with no brand. Apparently it was something I
> > >> 'should' know; or he actually listed the brand and I missed it.
>
> > >> This thread is too long to search it out.
>
> > >> jak
>
> > > I believe he has the B&H 802D's
>
> > >http://www.avrev.com/home-theater-loudspeakers/floorstanding-loudspea....
>
> Plus the place I bought the speakers from was trying to sell me 4 Classe
> amps.
>
> mike- Hide quoted text -
>
> - Show quoted text -

Now you're going to sart a whole nother debate, yukyuk :-)

[Peter Larsen[_3_]]

vMike > wrote:

> Plus the place I bought the speakers from was trying to sell me 4
> Classe amps.

The merit of the type of biamping you were considering is that it sells
amplifiers.

> mike

Kind regards

Peter Larsen

[GregS[_3_]]

In article >, "vMike" > wrote:
>
> wrote in message
...
>On Jan 30, 12:46 pm, jakdedert > wrote:
>> vMike wrote:
>> > > wrote in message
>> ...
>> > On Jan 29, 1:40 pm, jakdedert > wrote:
>> >> wrote:
>>
>> >> <snip>
>>
>> >>> If I owned those speakers I would very likely not consider trying to
>> >>> biamp them. Partly for some of the reasons you point out. Does that
>> >>> constitute agreeing with you? :-)
>> >> ?? Does someone have a link to the OP's speakers. AARC, he id'd them by
>> >> a model number (902?) with no brand. Apparently it was something I
>> >> 'should' know; or he actually listed the brand and I missed it.
>>
>> >> This thread is too long to search it out.
>>
>> >> jak
>>
>> > I believe he has the B&H 802D's
>>
>> >http://www.avrev.com/home-theater-loudspeakers/floorstanding-loudspea...
>
>
>Plus the place I bought the speakers from was trying to sell me 4 Classe
>amps.
>
>mike

You probably saved some good money !!

greg

[[email protected]]

On Jan 30, 12:45*pm, wrote:
> On Jan 30, 11:55*am, wrote:
>
> You have some valid points. *But if you would
> tone down the rant level some you would probably
> get them across better. *

The "rant level" in your words, is a direct and immediate
consequence of your misrepresentations and continued
assumptions about what I and others say, mean or intend.
Stick with what you know, I'll stick with what I know,
and you'll find the conversation less out of your control.

In otherwords, please don't be so presumptuous as to
tell me or anyone else what we do or do not know.
your statements such as "He's assuming that the
crossover in question has additional components..."
or " That they used "theory" when designing their
port suggests that they didn't really test anything,"
and the rest are uninformed, insulting rants of their
own.

You're revealed quite clearly you are not well versed
other than popular culture, myth and assumptions
about the physical and practical principles and concepts
of loudspeaker theory, design and implementation, yet
you choose to hold forth as an expert, making uniformed
and sometimes absurd pronouncements. Your comments
about what you consider appropriate or inappropriate
about the components that should be used is especially
revealing of your ignorance.

And I use "ignorance" not in the pejorative but the
factual sense, if you understand what that means.
I am ignorant of central Asian religions, and thus
have the good sense not to hold forth in those
forums. I do not find the fact that I am ignorant
in those topics to be anything other than a recognition
of fact.

It's only if I insist nd behave otherwise does my
ignorance on the topic turn me into an ignoramus.

> > > Some would point out capacitive too.
>
> > And so far, all the people you are referring to would
> > be wrong.
>
> > A woofer exhibits alternatively resistive, inductive,
> > resistive, capacitive, resistive and inductive components
> > to its impedance as we move up in frequency. But at
> > NO place is the impedance every anything other than
> > predominantly are largely resistive.
>
> Here you claim something to be wrong and yet
> in the next paragraph make the same statement. *

No, I do not.

> No where did I claim that any of these other
> characteristics exceed the resistive load. *

Nor did I accuse you of that.

> I have to guess that is the point of your second
> sentence though it is difficult to tell from the
> poor wording. *

I was objecting to, clarifying and detailing what
the impedance of a specific type of driver actually IS,
rather than your statements about simplistic and
incorrect models. The quotations you made are wrong,
as a point of physical fact, simpe as that. Deal with it
and move on.

> Are you saying that the only characteristic of the
> speaker that matters is the resistive load?

No, I did not say that. READ what I said:

"A woofer exhibits alternatively resistive,
inductive, resistive, capacitive, resistive
and inductive components to its impedance
as we move up in frequency. But at NO
place is the impedance every anything
other than predominantly are largely
resistive."

Where did I say that it's only one thing or another
that matters? Please point that out.

Would it have helped to say that with only very
rare exceptions does a loudspeaker exhibit an
impedance where the absolute value of the phase
angle exceeds 45 degrees? Any system that has
an impedance phase angle that is asymtotically
limited to +-45 degrees is by definition largely
resistive. That's a statement of physical fact.

Do you assert otherwise?

Do you know what this means?

Do you think every reader might know what
this means?

[Mr.T]

"GregS" > wrote in message
...
> I think you have to consider the crossover-driver interaction. If you
duplicated passive
> with active, the driver does not see the same thing. It sees the amplifier
output.
> You have to duplicated the whole action of the passive crossover in the
active crossover.

Not so. First you have to assume (possibly incorrectly) that there is a
negative affect from the passive Xover-speaker interaction to bother
changing it in the first place. *IF* that is in fact so, then replicating it
in an active crossover is the last thing you want to do!

However there are plenty of speakers with poorly designed Xovers that may
benefit from a half decently implemented active replacement.
I also agree with Dick that almost any B&W is unlikely to be among them.

Many sub-woofer passive Xovers are good targets though, but then most good
ones aren't passive in the first place.

MrT.

[[email protected]]

On Jan 30, 4:06*pm, wrote:
> On Jan 30, 12:45*pm, wrote:
>
> > On Jan 30, 11:55*am, wrote:
>
> > You have some valid points. *But if you would
> > tone down the rant level some you would probably
> > get them across better. *
>
> The "rant level" in your words, is a direct and immediate
> consequence of your misrepresentations and continued
> assumptions about what I and others say, mean or intend.
> Stick with what you know, I'll stick with what I know,
> and you'll find the conversation less out of your control.
>
> In otherwords, please don't be so presumptuous as to
> tell me or anyone else what we do or do not know.
> your statements such as "He's assuming that the
> crossover in question has additional components..."
> or " That they used "theory" when designing their
> port suggests that they didn't really test anything,"
> and the rest are uninformed, insulting rants of their
> own.
>
> You're revealed quite clearly you are not well versed
> other than popular culture, myth and assumptions
> about the physical and practical principles and concepts
> of loudspeaker theory, design and implementation, yet
> you choose to hold forth as an expert, making uniformed
> and sometimes absurd pronouncements. Your comments
> about what you consider appropriate or inappropriate
> about the components that should be used is especially
> revealing of your ignorance.
>
> And I use "ignorance" not in the pejorative but the
> factual sense, if you understand what that means.
> I am ignorant of central Asian religions, and thus
> have the good sense not to hold forth in those
> forums. I do not find the fact that I am ignorant
> in those topics to be anything other than a recognition
> of fact.
>
> It's only if I insist nd behave otherwise does my
> ignorance on the topic turn me into an ignoramus.
>
> > > > Some would point out capacitive too.
>
> > > And so far, all the people you are referring to would
> > > be wrong.
>
> > > A woofer exhibits alternatively resistive, inductive,
> > > resistive, capacitive, resistive and inductive components
> > > to its impedance as we move up in frequency. But at
> > > NO place is the impedance every anything other than
> > > predominantly are largely resistive.
>
> > Here you claim something to be wrong and yet
> > in the next paragraph make the same statement. *
>
> No, I do not.
>
> > No where did I claim that any of these other
> > characteristics exceed the resistive load. *
>
> Nor did I accuse you of that.
>
> > I *have to guess that is the point of your second
> > sentence though it is difficult to tell from the
> > poor wording. *
>
> I was objecting to, clarifying and detailing what
> the impedance of a specific type of driver actually IS,
> rather than your statements about simplistic and
> incorrect models. The quotations you made are wrong,
> as a point of physical fact, simpe as that. Deal with it
> and move on.
>
> > Are you saying that the only characteristic of the
> > speaker that matters is the resistive load?
>
> No, I did not say that. READ what I said:
>
> * *"A woofer exhibits alternatively resistive,
> * *inductive, resistive, capacitive, resistive
> * *and inductive components to its impedance
> * *as we move up in frequency. But at NO
> * *place is the impedance every anything
> * *other than predominantly are largely
> * *resistive."
>
> Where did I say that it's only one thing or another
> that matters? Please point that out.
>
> Would it have helped to say that with only very
> rare exceptions does a loudspeaker exhibit an
> impedance where the absolute value of the phase
> angle exceeds 45 degrees? Any system that has
> an impedance phase angle that is asymtotically
> limited to +-45 degrees is by definition largely
> resistive. That's a statement of physical fact.
>
> Do you assert otherwise?
>
> Do you know what this means?
>
> Do you think every reader might know what
> this means?

I said:
> > > Some would point out capacitive too.

You said:
> > And so far, all the people you are referring to would
> > be wrong.

How else could this sentence be interpreted as any thing but
disagreeing with my statement?

Then you went on to say:
> > A woofer exhibits alternatively resistive, inductive,
> > resistive, capacitive, resistive and inductive components

How could this be interpreted as saying anything other than a speaker
has capacitive characteristics?

Yes, my statements are simplistic. The point I was making was that
you can not design a crossover in a vacuum. The speakers and the
cabinet have an effect on the process as well. A point which I think
was what you also raised in comparison of an active crossover verses
the passive crossover? I did not think the addition complexities were
needed to make the point. Was there a different conclusion to be
drawn from your comparision of generic active verses a specific
passive design?

All communications is based on assumptions. People make statements.
The readers come to conclusions about what they think is being
stated. Those conclusions are assumptions. If wrong then the fault
is not always the reader.

Admittedly on the b&h speakers I am drawing conclusions without a
complete set of facts. Unfortunately in the real world we often have
to do that. I agree they are just opinions. But there is a noticable
different between the speed of sound though air and the speed of golf
balls.

Do you not think that ferite cores are an inferior inductor over air
core for use in passive crossovers? Or that electrolitic capacitors
are less likely to be high precision and have issues with the
capacitance changing due to aging?

[Peter Larsen[_3_]]

wrote:

> Do you not think that ferite cores are an inferior inductor over air
> core for use in passive crossovers?

You just do not have a clue.

Kind regards

Peter Larsen

[Mr.T]

"Peter Larsen" > wrote in message
...
> wrote:
>
> > Do you not think that ferite cores are an inferior inductor over air
> > core for use in passive crossovers?
>
> You just do not have a clue.

Actually he's partly right. The non linearities may be small in most cases,
and probably a lot less than the drivers themselves, and probably
inconsequential to the system performance, BUT as an absolute statement, and
assuming (yes big assumption) all other inductor parameters are the same,
(obviously ignoring cost, size etc) then the ferrite cored inductor *may* be
"inferior" to the air cored one.

However given all the caveats necessary for that, I'd say your statement is
probably the more accurate :-)

MrT.

[[email protected]]

On Feb 3, 9:18*pm, "Mr.T" <MrT@home> wrote:
> "Peter Larsen" > wrote in message
>
> ...
>
> > wrote:
>
> > > Do you not think that ferite cores are an inferior inductor over air
> > > core for use in passive crossovers?
>
> > You just do not have a clue.
>
> Actually he's partly right. The non linearities may be small in most cases,
> and probably a lot less than the drivers themselves, and probably
> inconsequential to the system performance, BUT as an absolute statement, and
> assuming (yes big assumption) all other inductor parameters are the same,
> (obviously ignoring cost, size etc) then the ferrite cored inductor *may* be
> "inferior" to the air cored one.
>
> However given all the caveats necessary for that, I'd say your statement is
> probably the more accurate :-)
>
> MrT.

I notice you both avoided the electrolitic question all together.

As to the air core verses ferite core cost is not a factor in this
case. The speakers in question have a suggested retail of $12k a pair.

[[email protected]]

On Feb 3, 6:27*pm, "Peter Larsen" > wrote:
> wrote:
> > Do you not think that ferite cores are an inferior inductor over air
> > core for use in passive crossovers?
>
> You just do not have a clue.
>
> * Kind regards
>
> * Peter Larsen

That's funny cause I'm starting to think you are an egotistical know-
it-all that has driven away all his real friends so he now spends his
time trying to prove to everyone on the internet how smart he is.
How's that for a clue?

[Mr.T]

> wrote in message
...
>I notice you both avoided the electrolitic question all together.

Similar arguments apply, especially at lower frequencies where large values
of capacitance may be required. Most manufacturers will avoid electro's if
they can, so I'll bet B&W don't use a 1uF electro for example.

>As to the air core verses ferite core cost is not a factor in this
>case. The speakers in question have a suggested retail of $12k a pair.

How can cost not be a factor? Even B&W makes more expensive speakers than
that! As do a large number of manufacturers. Some compromises must be made
to hit that price point. You'd prefer cheaper drivers and better inductors
perhaps?

In any case there are other factors to consider like size and weight for
example, if you want high power and low resistance. People these days seem
to dislike speakers the size and weight of refrigerators, even though they
usually have less compromises IMO :-)

MrT.

[David Nebenzahl]

On 2/4/2009 11:20 AM spake thus:

> I notice you both avoided the electrolitic question all together.

You know, if you're going to discuss something technical as if you knew
anything about it, you might as well try to spell it right.

It's *electrolytic*.

You're welcome.


--
Personally, I like Vista, but I probably won't use it. I like it
because it generates considerable business for me in consulting and
upgrades. As long as there is hardware and software out there that
doesn't work, I stay in business. Incidentally, my company motto is
"If this stuff worked, you wouldn't need me".

- lifted from sci.electronics.repair

[[email protected]]

On Feb 4, 7:30*pm, "Mr.T" <MrT@home> wrote:
> > wrote in message
>
> ...
>
> >I notice you both avoided the electrolitic question all together.
>
> Similar arguments apply, especially at lower frequencies where large values
> of capacitance may be required. Most manufacturers will avoid electro's if
> they can, so I'll bet B&W don't use a 1uF electro for example.
>
> >As to the air core verses ferite core cost is not a factor in this
> >case. *The speakers in question have a suggested retail of $12k a pair..
>
> How can cost not be a factor? Even B&W makes more expensive speakers than
> that! As do a large number of manufacturers. Some compromises must be made
> to hit that price point. You'd prefer cheaper drivers and better inductors
> perhaps?
>
> In any case there are other factors to consider like size and weight for
> example, if you want high power and low resistance. People these days seem
> to dislike speakers the size and weight of refrigerators, even though they
> usually have less compromises IMO :-)
>
> MrT.

I'm having a hard time seeing a difference in cost at this price range
or weight to explain it. These speakers are suggested retail of $12k
a pair and weigh a whopping176 lbs each. If you wanted to make a case
that other factors are more significant than these component choices I
might go for it. Or maybe they just couldn't come up with some flashy
sounding sales hype for them. My hypo-meter is already going off
anyway. I'm sure these speakers sound great but for me finding out
they used ferrite cores and eletrolitics is a bit like finding out
your ferrari has cast pistons.

I mean 'vapor depositing carbon' on the tweeter? I see no mention of
what the substrate is. Or just how many micrometers of carbon they
deposit. Think there is real science behind the benefits of
depositing carbon on the surface of a tweeter? Or is it just cool to
say "diamond tweeter'.

And 'dimpled much like a golf ball'? Admittedly the ability for a
computer simulate the behavior of the boundary layer is very advanced
these days. I'd still like to see some lab results. Think those
really exist? Think the effect of the boundary layer inside the port
is significant compared to the opening turbulence?

Interestingly these speakers have two sets of terminals and they are
jumpered. It's difficult to tell for certain but it seems that one
set does connect to the low side. The passive crossover spec for the
low is 350hz. Seems to me that even though the passive crossover
remains in the system, placing an active crossover also set at 350hz
up stream of two amps would have no detrimental effect? I do believe
that there is a benefit to having the mid/high swinging at the amp
output center rather than sitting on top of some massive bass note.

[Peter Larsen[_3_]]

Mr.T <MrT@home> wrote:

> "Peter Larsen" > wrote in message
> ...

>> wrote:

>>> Do you not think that ferite cores are an inferior inductor over air
>>> core for use in passive crossovers?

>> You just do not have a clue.

> Actually he's partly right. The non linearities may be small in most
> cases, and probably a lot less than the drivers themselves, and
> probably inconsequential to the system performance, BUT as an
> absolute statement, and assuming (yes big assumption) all other
> inductor parameters are the same, (obviously ignoring cost, size etc)
> then the ferrite cored inductor *may* be "inferior" to the air cored
> one.

IF a core was a conductor you - and he - would be in agreement with my
religion on this, but a core is a metal piece inside a coil of conducting
wire. But then there is the cost of the required amount of copper to get
similar resistance in the air cored coil, and it ends up with an active
cross-over being cheaper to implement than a high quality passive.

> However given all the caveats necessary for that, I'd say your
> statement is probably the more accurate :-)

Mr. Raymond Cooke of KEF preferred cored coils because that allowed him to
dimension them to protect the units. Unofficial information received from
the guys who imported KEF to Denmark way long time ago.

> MrT.

Kind regards

Peter Larsen

[Peter Larsen[_3_]]

wrote:

> On Feb 3, 6:27 pm, "Peter Larsen" > wrote:
>> wrote:

>>> Do you not think that ferite cores are an inferior inductor over air
>>> core for use in passive crossovers?

>> You just do not have a clue.

>> Kind regards

>> Peter Larsen

> That's funny cause I'm starting to think you are an egotistical know-
> it-all that has driven away all his real friends so he now spends his
> time trying to prove to everyone on the internet how smart he is.

Some of the time I do come across as arrogant because of occasionally
refusing to dúmb my typing down. I don't have a problem with it. If you DO
have a problem with it, then just skip what I write.

> How's that for a clue?

You do NOT have a clue when you describe a coil core, be it air or metal, as
a conductor. The current to the loudspeaker does NOT pass through it.

Kind regards

Peter Larsen

[GregS[_3_]]

In article >, wrote:
>On Feb 4, 7:30=A0pm, "Mr.T" <MrT@home> wrote:
>> > wrote in message
>>
>> ...
>>
>> >I notice you both avoided the electrolitic question all together.
>>
>> Similar arguments apply, especially at lower frequencies where large valu=
>es
>> of capacitance may be required. Most manufacturers will avoid electro's i=
>f
>> they can, so I'll bet B&W don't use a 1uF electro for example.
>>
>> >As to the air core verses ferite core cost is not a factor in this
>> >case. =A0The speakers in question have a suggested retail of $12k a pair=
>..
>>
>> How can cost not be a factor? Even B&W makes more expensive speakers than
>> that! As do a large number of manufacturers. Some compromises must be mad=
>e
>> to hit that price point. You'd prefer cheaper drivers and better inductor=
>s
>> perhaps?
>>
>> In any case there are other factors to consider like size and weight for
>> example, if you want high power and low resistance. People these days see=
>m
>> to dislike speakers the size and weight of refrigerators, even though the=
>y
>> usually have less compromises IMO :-)
>>
>> MrT.
>
>I'm having a hard time seeing a difference in cost at this price range
>or weight to explain it. These speakers are suggested retail of $12k
>a pair and weigh a whopping176 lbs each. If you wanted to make a case
>that other factors are more significant than these component choices I
>might go for it. Or maybe they just couldn't come up with some flashy
>sounding sales hype for them. My hypo-meter is already going off
>anyway. I'm sure these speakers sound great but for me finding out
>they used ferrite cores and eletrolitics is a bit like finding out
>your ferrari has cast pistons.

In keeping with space requirments and resistance, an inductor may have
been necessary.

>I mean 'vapor depositing carbon' on the tweeter? I see no mention of
>what the substrate is. Or just how many micrometers of carbon they
>deposit. Think there is real science behind the benefits of
>depositing carbon on the surface of a tweeter? Or is it just cool to
>say "diamond tweeter'.

Maybe it works.

>And 'dimpled much like a golf ball'? Admittedly the ability for a
>computer simulate the behavior of the boundary layer is very advanced
>these days. I'd still like to see some lab results. Think those
>really exist? Think the effect of the boundary layer inside the port
>is significant compared to the opening turbulence?
>
>Interestingly these speakers have two sets of terminals and they are
>jumpered. It's difficult to tell for certain but it seems that one
>set does connect to the low side. The passive crossover spec for the
>low is 350hz. Seems to me that even though the passive crossover
>remains in the system, placing an active crossover also set at 350hz
>up stream of two amps would have no detrimental effect? I do believe
>that there is a benefit to having the mid/high swinging at the amp
>output center rather than sitting on top of some massive bass note.

No. You don't do it that way. A crossover is only a generic name for a specifically
designed system with a lot of variables. If you add another crossover, you have no idea
what your getting to.

greg

[[email protected]]

On Feb 5, 12:24*pm, (GregS) wrote:
> In article >, wrote:
>
>
>
>
>
> >On Feb 4, 7:30=A0pm, "Mr.T" <MrT@home> wrote:
> >> > wrote in message
>
> ....
>
> >> >I notice you both avoided the electrolitic question all together.
>
> >> Similar arguments apply, especially at lower frequencies where large valu=
> >es
> >> of capacitance may be required. Most manufacturers will avoid electro's i=
> >f
> >> they can, so I'll bet B&W don't use a 1uF electro for example.
>
> >> >As to the air core verses ferite core cost is not a factor in this
> >> >case. =A0The speakers in question have a suggested retail of $12k a pair=
> >..
>
> >> How can cost not be a factor? Even B&W makes more expensive speakers than
> >> that! As do a large number of manufacturers. Some compromises must be mad=
> >e
> >> to hit that price point. You'd prefer cheaper drivers and better inductor=
> >s
> >> perhaps?
>
> >> In any case there are other factors to consider like size and weight for
> >> example, if you want high power and low resistance. People these days see=
> >m
> >> to dislike speakers the size and weight of refrigerators, even though the=
> >y
> >> usually have less compromises IMO :-)
>
> >> MrT.
>
> >I'm having a hard time seeing a difference in cost at this price range
> >or weight to explain it. *These speakers are suggested retail of $12k
> >a pair and weigh a whopping176 lbs each. If you wanted to make a case
> >that other factors are more significant than these component choices I
> >might go for it. *Or maybe they just couldn't come up with some flashy
> >sounding sales hype for them. *My hypo-meter is already going off
> >anyway. *I'm sure these speakers sound great but for me finding out
> >they used ferrite cores and eletrolitics is a bit like finding out
> >your ferrari has cast pistons.
>
> In keeping with space requirments and resistance, an inductor may have
> been necessary.
>
> >I mean 'vapor depositing carbon' on the tweeter? *I see no mention of
> >what the substrate is. *Or just how many micrometers of carbon they
> >deposit. *Think there is real science behind the benefits of
> >depositing carbon on the surface of a tweeter? *Or is it just cool to
> >say "diamond tweeter'.
>
> Maybe it works.
>
> >And 'dimpled much like a golf ball'? *Admittedly the ability for a
> >computer simulate the behavior of the boundary layer is very advanced
> >these days. *I'd still like to see some lab results. *Think those
> >really exist? *Think the effect of the boundary layer inside the port
> >is significant compared to the opening turbulence?
>
> >Interestingly these speakers have two sets of terminals and they are
> >jumpered. *It's difficult to tell for certain but it seems that one
> >set does connect to the low side. *The passive crossover spec for the
> >low is 350hz. *Seems to me that even though the passive crossover
> >remains in the system, placing an active crossover also set at 350hz
> >up stream of two amps would have no detrimental effect? *I do believe
> >that there is a benefit to having the mid/high swinging at the amp
> >output center rather than sitting on top of some massive bass note.
>
> No. You don't do it that way. A crossover is only a generic name for a specifically
> designed system with a lot of variables. If you add another crossover, you have no idea
> what your getting to.
>
> greg- Hide quoted text -
>
> - Show quoted text -

Yes, I'll admit that's possible. We have no idea what the slope of
the internal crossover is. And the addition of another slope does
have a effect. If the internal slope is high, say 24bd, would it
really matter if we made it sharper because of an external crossover
as long as we did not introduce any phase shift? The passive
crossover is already designed to be connected directly to an amp.

They have apparently designed the speaker so that the woofers could be
connected to a different amp from the mid/high. I see no advantage to
that configuration unless you have an active crossover upstream. I
did not find anything online about how to use the feature.

[[email protected]]

On Feb 5, 12:23*pm, "Peter Larsen" > wrote:
> wrote:
> > On Feb 3, 6:27 pm, "Peter Larsen" > wrote:
> >> wrote:
> >>> Do you not think that ferite cores are an inferior inductor over air
> >>> core for use in passive crossovers?
> >> You just do not have a clue.
> >> Kind regards
> >> Peter Larsen
> > That's funny cause I'm starting to think you are an egotistical know-
> > it-all that has driven away all his real friends so he now spends his
> > time trying to prove to everyone on the internet how smart he is.
>
> Some of the time I do come across as arrogant because of occasionally
> refusing to dúmb my typing down. I don't have a problem with it. If you DO
> have a problem with it, then just skip what I write.
>
> > How's that for a clue?
>
> You do NOT have a clue when you describe a coil core, be it air or metal, as
> a conductor. The current to the loudspeaker does NOT pass through it.
>
> * Kind regards
>
> * Peter Larsen

I never suggested that the current to the speaker passes through the
core. You get jump to the conclusion that I suggested the speaker
current passes through the core. Go ahead, find that in one of my
posts.

The concern is that any metal core introduces yet additional
properties to the inductor. And you know that it does. If you want
to take the position that they are negligible in this situation that's
fine.

[Peter Larsen[_3_]]

wrote:

>>>>> Do you not think that ferite cores are an inferior inductor over

> I never suggested that the current to the speaker passes through the
> core. You get jump to the conclusion that I suggested the speaker
> current passes through the core. Go ahead, find that in one of my
> posts.

I misread you as you can see from my followup to T, I'm sorry.

> The concern is that any metal core introduces yet additional
> properties to the inductor. And you know that it does. If you want
> to take the position that they are negligible in this situation that's
> fine.

I didn't.

Kind regards

Peter Larsen

[Mr.T]

"Peter Larsen" > wrote in message
...
> IF a core was a conductor you - and he - would be in agreement with my
> religion on this, but a core is a metal piece inside a coil of conducting
> wire.

Yes, and metal cores have some hysterisis, as does ferrite.

>But then there is the cost of the required amount of copper to get
> similar resistance in the air cored coil,

As already mentioned, and size, weight etc.

> Mr. Raymond Cooke of KEF preferred cored coils because that allowed him to
> dimension them to protect the units.

What does that mean?

MrT.

[Mr.T]

> wrote in message
...
>Yes, I'll admit that's possible. We have no idea what the slope of
>the internal crossover is. And the addition of another slope does
>have a effect. If the internal slope is high, say 24bd, would it
>really matter if we made it sharper because of an external crossover
>as long as we did not introduce any phase shift?

Of course you would, the overlap region will be reduced which may create a
response dip for example.

>The passive
>crossover is already designed to be connected directly to an amp.

And is already designed (or should be) to give the flattest response with
that combination of drivers.

>They have apparently designed the speaker so that the woofers could be
>connected to a different amp from the mid/high. I see no advantage to
>that configuration unless you have an active crossover upstream.

Actually there is still a benefit even if both amps are full range. You can
use a bigger amp for the bass, and a smaller one that *may* give better
performance at the higher frequencies. It is usually easier to make a
smaller amp with less noise for example.

And then some people also believe in simple Bi-wiring, and it's so easy to
provide for, that many manufacturers do.

MrT.

[Peter Larsen[_3_]]

Mr.T <MrT@home> wrote:

>> Mr. Raymond Cooke of KEF preferred cored coils because that allowed
>> him to dimension them to protect the units.

> What does that mean?

Saturation is not always a bad thing. Getting too close to in in normal use
is however, I have heard a dramatic system improvement in the deep bass
range when a cored coil was replaced by an air cored.

> MrT.

Kind regards

Peter Larsen

[Mr.T]

"Peter Larsen" > wrote in message
...
> >> Mr. Raymond Cooke of KEF preferred cored coils because that allowed
> >> him to dimension them to protect the units.
>
> > What does that mean?
>
> Saturation is not always a bad thing.

OK, how does the core saturation of the coil help protect the drive unit?
Possibly in a HF bypass coil I guess. Pity they are easier to make air cored
than in the LF range.

>I have heard a dramatic system improvement in the deep bass
> range when a cored coil was replaced by an air cored.

So now you are agreeing with James?

MrT.

[[email protected]]

On Feb 6, 12:04*am, "Mr.T" <MrT@home> wrote:
> "Peter Larsen" > wrote in message
>
> ...
>
> > >> Mr. Raymond Cooke of KEF preferred cored coils because that allowed
> > >> him to dimension them to protect the units.
>
> > > What does that mean?
>
> > Saturation is not always a bad thing.
>
> OK, how does the core saturation of *the coil help protect the drive unit?
> Possibly in a HF bypass coil I guess. Pity they are easier to make air cored
> than in the LF range.
>
> >I have heard a dramatic system improvement in the deep bass
> > range when a cored coil was replaced by an air cored.
>
> So now you are agreeing with James?
>
> MrT.

Let's not get carried away, where's the fun in that.

[[email protected]]

On Feb 5, 8:57*pm, "Mr.T" <MrT@home> wrote:
> > wrote in message
>
> ...
>
> >Yes, I'll admit that's possible. *We have no idea what the slope of
> >the internal crossover is. *And the addition of another slope does
> >have a effect. *If the internal slope is high, say 24bd, would it
> >really matter if we made it sharper because of an external crossover
> >as long as we did not introduce any phase shift?
>
> Of course you would, the overlap region will be reduced which may create a
> response dip for example.
>
> >The passive
> >crossover is already designed to be connected directly to an amp.
>
> And is already designed (or should be) to give the flattest response with
> that combination of drivers.
>
> >They have apparently designed the speaker so that the woofers could be
> >connected to a different amp from the mid/high. *I see no advantage to
> >that configuration unless you have an active crossover upstream.
>
> Actually there is still a benefit even if both amps are full range. You can
> use a bigger amp for the bass, and a smaller one that *may* give better
> performance at the higher frequencies. It is usually easier to make a
> smaller amp with less noise for example.
>
> And then some people also believe in simple Bi-wiring, and it's so easy to
> provide for, that many manufacturers do.
>
> MrT.

Nothing personal but I'm afraid I disagree completely about two amps
running full range. Frankly I believe the only gain in bi-amping is
to separate the signal and isolate the larger bass signal from the
rest. And bi-wiring is just total crap. People used to believe the
world was flat, that was crap too.

So perhaps the solution is to send the 250hz and up range to the high
amp and the 450hz and down range to the low amp. Then the slope of
the active crossovers starts 50hz away from the passive ones. No
longer your off the shelf active crossover now though. But since it
would be a fixed crossover points it would be a simple matter to
construct a high impedance one.

[Peter Larsen[_3_]]

Mr.T <MrT@home> wrote:

> "Peter Larsen" > wrote in message
> ...

>>>> Mr. Raymond Cooke of KEF preferred cored coils because that allowed
>>>> him to dimension them to protect the units.

>>> What does that mean?

>> Saturation is not always a bad thing.

> OK, how does the core saturation of the coil help protect the drive
> unit? Possibly in a HF bypass coil I guess. Pity they are easier to
> make air cored than in the LF range.

>> I have heard a dramatic system improvement in the deep bass
>> range when a cored coil was replaced by an air cored.

> So now you are agreeing with James?

My point of view remains that it the cost of making a ""proper"" passive
crossover is so high that it is folly to so do. A bass unit that sounds
better with an air cored coil than with a ferrite cored coil still sounds
best with no coil between it and the amp. Consequently I'd never bother with
replacing the ferrite cored coil and I remain convinced that one should not
so do in case of a computer optimized cross-over because its exact
properties are factored in and one might get a mid range cost for the better
orchestral bass drum.

> MrT.

Kind regards

Peter Larsen