Last Saturday I spent some time with one of my clients to assist him
with his sound system, where the speakers consist of some quite old
Altec cast aluminium horns and large ported boxes with 15" woofers..
He is biamping the above, but will be triamping reflex bass speakers and
mid and
treble horn speakers.
A few weeks ago we tested the horns to find they gave very different
response and sensitivity contours, thus indicating one or both had
stuffed diapragms.
The result was very honky lack lustre sound.
Last Saturday we replaced the drivers with a NOS pair he found,
and each horn then gave the same nice arched bandpass response using
the same input voltage of pink noise noise signal and same mic at 3
metres away
The curves of L and R were within a dB of each other.
The test confirmed that pink noise is a very useful way of measuring
response.

I set up the pink noise test signal about as loud
as music on the horns and measured
0.04 vrms of signal.
This is 0.2 milliwatt.
The horns are 105 dB/W/M efficient, and 0.2mW give about 68dBSPL at a
metre,
maybe 66 db at 3M in a room, but plenty loud enough to overcome
street noise outside, and other house noises, and quite measurable by my
test mic
with negligible distortions.
An SE 300B is used for these midrange horns which are set for 500Hz
crossover from the bass,
and which go to about 7 kHz.
He has McIntosh 60 watt mono PP amps for the bass 15" which measured
far less sensitive than the mid horns.
He will be using 2A3 amps I am building for his proposed tweeter horns
which cover from 7kHz upwards.
I doubt he'd ever use more than 1/2 a watt total, for all 6 speakers in
the system.

He'd be quite OK with just the 300B amps for all
the speakers with passive Xovers.
We are considering placing capacitors in series with the mid and treble
amps
and the horns just in case a burst of LF hum accidently takes out one of
the horn
speaker voice coils.

So even though one aims to remove things in series
with speakers, one still has to protect them

He still has the issue of the active crossover in series between preamp
and
power amps, and it can colour or ruin the tube
sound, and this unit is an SS opamp based contraption .....

When i get the tweeter amps built, we will be switching to use of an ARC
3 way crossover,
and this old thing looks like it was made before ARC went all strange
and designed all their
circuits with 15dB too many parts. It just has 6 twin triodes inside,
and some simple
looking circuit boards, on which the R&C parts can be changed to suit
the wanted
crossover points.

This guy would be quite lost trying to figure it out on his own.
He's the director of a trade commission, and a complete gentleman,
but not a man with any experience of comprehending the physics
of what he's doing.
If you don't know how to figure all this stuff out, its quite
understandable,
maybe only 15% of dudes at r.a.t have any idea at all,
and to make sure one has it right takes knowing someone you could trust
to fiddle with your speakers with the right gear.

We had a listen to the system which we now know has at least 4 good
speakers,
and the sound was a vast improvement over the honky sound we heard
a few weeks back.
And all this despite the top end completely missing.
In fact I could say his system shows signs of changing my prejudice
that
all horns tend to suck; here we have a pair that were doing rather well
with
music.

He still has a long way to go before gets the best sound possible.
His room has a timber floor, and the usual hard plastered walls and
ceiling,
so the reverbrations are seriously affecting his sound, but when he gets
a large thick
rug and completes some shelves for his vinyl collections he will hear
much better sound.

Patrick Turner.

In article ,
Patrick Turner wrote:
Last Saturday I spent some time with one of my clients to assist him
with his sound system, where the speakers consist of some quite old
Altec cast aluminium horns and large ported boxes with 15" woofers..
He is biamping the above, but will be triamping reflex bass speakers and
mid and

There were articles in Radio-Electronics magazine in the 50's and (I think)
early 60's describing various setups.

One setup was tri-amplified, using a large hyperbolic horn for the single
mono subwoofer; this was called the "Wooden Monster". The crossovers and
amps were standard 1950's designs, i.e., beam power tetrodes (I think) in
push-pull on the outputs.

I am playing with a similar system based on the JBL S8R system and would be
interested in what you discover about biamping such a system.

Mike Squires
--

Mike Squires (mikes at cs.indiana.edu) 317 233 9456 (w) 812 333 6564 (h)
mikes at siralan.org 546 N Park Ridge Rd., Bloomington, IN 47408

Michael Squires wrote:

In article ,
Patrick Turner wrote:
Last Saturday I spent some time with one of my clients to assist him
with his sound system, where the speakers consist of some quite old
Altec cast aluminium horns and large ported boxes with 15" woofers..
He is biamping the above, but will be triamping reflex bass speakers and
mid and

There were articles in Radio-Electronics magazine in the 50's and (I think)
early 60's describing various setups.

One setup was tri-amplified, using a large hyperbolic horn for the single
mono subwoofer; this was called the "Wooden Monster". The crossovers and
amps were standard 1950's designs, i.e., beam power tetrodes (I think) in
push-pull on the outputs.

Yes, there have been a few Monsterious Woodenium bass horn speakers,
but none require a pair of tetrodes since only the smallest poofteenth of a watt

is needed to shift a bit of air when well connected to a driver with a horn.
The trouble with hornless woofers is that they are like a fist jabbing at the
air;
they puncture the air, they cannot grabhold of it and shove it,
unless you make a BIIIIIIGGGG diameter cone, but the weight goes up, efficiency
down,
and there is cone breakup, so a horn starts to look
like a good way to connect a mass of air to a magnetic voice coil.
Having said that, its amazing how much bass comes from a relatively stiff
concoction of woodwork and strings, the double bass.
But they won't go down to 20Hz.
To get 20Hz bass horn size is of course totally impractical, and I have yet to
hear one that
ever did much good, often giving a very uneven and odd response below 200 Hz,
because their makers couldn't resist the foreshortening and masses of bends.
Altec may have realized all this and hence the system with bass reflex in large
boxes,
and you need a lot more power. But they still give 95 dB/W/M, so
they still put out a lot with little power.
There is no need for any greater complexity than that with a simple SET amp, and
although
I didn't plot the Z curve for the horns we set up on the weekend I suspect
it is benign, and not needing to have a super high damping factor to overcome
the problems of maintaining a level acoustic response with a wildly
changing Z by means of having Ro lower than 1ohm, which means that FB has to be
used even
with most triodes.




I am playing with a similar system based on the JBL S8R system and would be
interested in what you discover about biamping such a system.

I may have the 2A3 amps done for the tweeters in a month and installed, so it
will be interesting
if we can coax more music.
I don't like the ARC SP11 preamp and SS active crossover my client is using.
Up to hundreds of solid state devices in the hybrid SP11 and SS active Xover
can then be removed from the signal path.
These all don't belong in the system, and when he farewells both he will do OK
and even better when he fixes up his room with a decent HUGE thick rug,
and we may get some sweetness, some untrammelled detail, some air,
some musicality and more real warmth.

Patrick Turner.



Mike Squires
--

Mike Squires (mikes at cs.indiana.edu) 317 233 9456 (w) 812 333 6564 (h)
mikes at siralan.org 546 N Park Ridge Rd., Bloomington, IN 47408

On Mon, 30 May 2005 09:30:19 GMT, Patrick Turner
wrote:

Last Saturday I spent some time with one of my clients to assist him
with his sound system, where the speakers consist of some quite old
Altec cast aluminium horns and large ported boxes with 15" woofers..
He is biamping the above, but will be triamping reflex bass speakers and
mid and
treble horn speakers.
A few weeks ago we tested the horns to find they gave very different
response and sensitivity contours, thus indicating one or both had
stuffed diapragms.
The result was very honky lack lustre sound.
Last Saturday we replaced the drivers with a NOS pair he found,
and each horn then gave the same nice arched bandpass response using
the same input voltage of pink noise noise signal and same mic at 3
metres away
The curves of L and R were within a dB of each other.
The test confirmed that pink noise is a very useful way of measuring
response.

I set up the pink noise test signal about as loud
as music on the horns and measured
0.04 vrms of signal.
This is 0.2 milliwatt.
The horns are 105 dB/W/M efficient, and 0.2mW give about 68dBSPL at a
metre,
maybe 66 db at 3M in a room, but plenty loud enough to overcome
street noise outside, and other house noises, and quite measurable by my
test mic
with negligible distortions.
An SE 300B is used for these midrange horns which are set for 500Hz
crossover from the bass,
and which go to about 7 kHz.
He has McIntosh 60 watt mono PP amps for the bass 15" which measured
far less sensitive than the mid horns.
He will be using 2A3 amps I am building for his proposed tweeter horns
which cover from 7kHz upwards.
I doubt he'd ever use more than 1/2 a watt total, for all 6 speakers in
the system.

He'd be quite OK with just the 300B amps for all
the speakers with passive Xovers.
We are considering placing capacitors in series with the mid and treble
amps
and the horns just in case a burst of LF hum accidently takes out one of
the horn
speaker voice coils.

So even though one aims to remove things in series
with speakers, one still has to protect them

He still has the issue of the active crossover in series between preamp
and
power amps, and it can colour or ruin the tube
sound, and this unit is an SS opamp based contraption .....

When i get the tweeter amps built, we will be switching to use of an ARC
3 way crossover,
and this old thing looks like it was made before ARC went all strange
and designed all their
circuits with 15dB too many parts. It just has 6 twin triodes inside,
and some simple
looking circuit boards, on which the R&C parts can be changed to suit
the wanted
crossover points.

This guy would be quite lost trying to figure it out on his own.
He's the director of a trade commission, and a complete gentleman,
but not a man with any experience of comprehending the physics
of what he's doing.
If you don't know how to figure all this stuff out, its quite
understandable,
maybe only 15% of dudes at r.a.t have any idea at all,
and to make sure one has it right takes knowing someone you could trust
to fiddle with your speakers with the right gear.

We had a listen to the system which we now know has at least 4 good
speakers,
and the sound was a vast improvement over the honky sound we heard
a few weeks back.
And all this despite the top end completely missing.
In fact I could say his system shows signs of changing my prejudice
that
all horns tend to suck; here we have a pair that were doing rather well
with
music.

He still has a long way to go before gets the best sound possible.
His room has a timber floor, and the usual hard plastered walls and
ceiling,
so the reverbrations are seriously affecting his sound, but when he gets
a large thick
rug and completes some shelves for his vinyl collections he will hear
much better sound.

Patrick Turner.



I have an old spk system like that, I'd be interested in hearing how you
equalize the horn response...

I think Altek used to have a crossover with mid and treble controls on it...

My system uses a horn tweeter for the highs, xover around 10,000Hz.

Bob wrote:


I have an old spk system like that, I'd be interested in hearing how you
equalize the horn response...

I think Altek used to have a crossover with mid and treble controls on it...

We are not using the existing Xovers in the bass boxes.

The final arrangement of each channel will be a preamp feeding
an tubed ARC 3 way active crossover, then 3 power amps, one for each speaker in
the channel.
Values will be chosen to make Xovers at 500Hz and 6kHz.
Pink noise testing will be used to get as flat a response as possible,
and that may need some fiddling with C values in the active Xover unit
and level adjusting. It may take several hours to set up properly.
I will be insisting my client buy a large thick rug to fix the horrible acoustics
of the room
before I attempt to tune his system.

Patrick Turner.




My system uses a horn tweeter for the highs, xover around 10,000Hz.

"Patrick Turner" wrote in message
...

He still has the issue of the active crossover in series between preamp
and
power amps, and it can colour or ruin the tube
sound, and this unit is an SS opamp based contraption .....

**Please explain how this is possible.


--
Trevor Wilson
www.rageaudio.com.au

Trevor Wilson wrote:

"Patrick Turner" wrote in message
...

He still has the issue of the active crossover in series between preamp
and
power amps, and it can colour or ruin the tube
sound, and this unit is an SS opamp based contraption .....

**Please explain how this is possible.

It would be a waste of time to discuss whether SS is any better than tubes.
PPL here already know the answers.

What I said was "it can ruin..."

Maybe it does, maybe it don't, heck, I have not measured the unit.

I don't like bi or tri amping or active Xovers myself, but
I am ready to help anyone who wants to do it;
Usually i am saving them from themselves, since to get such things right
involves some technical expertise, sadly lacking amoungst
some audio amateurs who believe they can just plug and play,
and assume "she'll be right".

Patrick Turner.




--
Trevor Wilson
www.rageaudio.com.au

"Patrick Turner" wrote in message
...


Trevor Wilson wrote:

"Patrick Turner" wrote in message
...

He still has the issue of the active crossover in series between preamp
and
power amps, and it can colour or ruin the tube
sound, and this unit is an SS opamp based contraption .....

**Please explain how this is possible.

It would be a waste of time to discuss whether SS is any better than
tubes.
PPL here already know the answers.

What I said was "it can ruin..."

**How? Be precise in your answer please.


Maybe it does, maybe it don't, heck, I have not measured the unit.

**Then why make such an inane comment. I recently employed a cheap, digital
Behringer crossover in a system. It's noise, distortion and frequency
response figures are well beyond the ability of any human to detect. It's
figures (and therefore, it's sound quality) are far better than any SET
product.


--
Trevor Wilson
www.rageaudio.com.au

Trevor Wilson wrote:

"Patrick Turner" wrote in message
...


Trevor Wilson wrote:

"Patrick Turner" wrote in message
...

He still has the issue of the active crossover in series between preamp
and
power amps, and it can colour or ruin the tube
sound, and this unit is an SS opamp based contraption .....

**Please explain how this is possible.

It would be a waste of time to discuss whether SS is any better than
tubes.
PPL here already know the answers.

What I said was "it can ruin..."

**How? Be precise in your answer please.


Maybe it does, maybe it don't, heck, I have not measured the unit.

**Then why make such an inane comment. I recently employed a cheap, digital
Behringer crossover in a system. It's noise, distortion and frequency
response figures are well beyond the ability of any human to detect. It's
figures (and therefore, it's sound quality) are far better than any SET
product.

You are another one who doesn't belong in this news group.


The last time you had any real interest in constructing something with a tube in
it was
maybe 30 years ago.


What I said to Pinkerton, otherwise well known as ""Oinkerton"",
applies to YOU, because he became like the man who insists on selling pork in a
synagogue,
ie, he tried to tell us to give up our tubes and go squalid state.

Since "Oinky" has so very little to contribute to
the understanding of tube craft and the use of tubes in audio systems,
he didn't last here as a permanent fixture, and nor will you, should you wish to
unjustafiably
**** on all of us over the issue of SET amps, which I may add can make excellent
amplifiers,
a fact that has yet to register in your brain.
People can feel free to go through the archives for aus.hi-fi where at hi-fi
where you have a dismal record at dismissing legitimate amplifier systems.


So should you wish to become to be seen as another un-informative and
destructive fool,
keep blathering the way you are about SET amps, you have the right,
but you will loose any slight respect you have here.

As for the Behringer, who knows, maybe its better or worse than anything else.
You would have to work harder to convince us we cannot do without one.
There is one at

http://www.behringer.com/CX3400/index.cfm?lang=ENG

Its aud $300.00

And a more expensive looking one at

http://www.behringer.com/DCX2496/index.cfm?lang=ENG

The pdf spec sheet of the CX3400 gives thd 0.04%, which is more than
what a tubed active crossover using SET topologies could easily achieve.


But it is another gadget in the signal path.
It should be more benign than a set of passive normal crossovers,
because I am told it has none of the phase shift with LCRs or the RC networks
used
in feedback networks around opamps.
I am not all that sure that the phase shift is all that much trouble,
if the audio amateur understands how to allow for it.
When i rebuild crossovers for normal speakers which I am called to
re-engineer professionally, It is a PITA to have to keep phase shift in mind
at all times, lest signals cancel each other or add in ways to upset the
response.
Unfortunately, speakers also display level responses that are rarely
ever near flat as we might wish, and a theoretical choice of crossover point
between two speakers may not work in practice, and the speakers must be
measured to verify how you really want to set up the crossovers,
so that a reasonably flat response is achieved. Not only must the crossover
serve to
divide F to various drivers but they must compensate for varying acoustic
output in their bands, and a theortical Xover rarely is ever one that
works exactly as intended in practice without some trimming.

An absense of phase shift in a crossover would be a blessing,
but its not entirely necessary, and any recorded signal has a different phase
print than the live performance,
so phase shift is always going to be with us, and one link in the audio chain
with no phase shift
won't be a cure all.

For analog Xovers I'd rather have a simple tube based active crossover for
bi/triamping.
The only problem with such like is the inflexibilty.
One has to be sure about levels and poles and speaker selections and level
compensations because it is
hard to make a change and still keep the system optimal if the F poles are
determined by
soldering in various capacitors or resistors.
I'd also maybe prefer a passive LCR crossover, in other words, something
with a minimal number of components, and a bare minimum of phase shift,
requiring nothing more than a low Ra triode CF to drive it, since
to get basic roll-off attenuation rates, the signal source must be a voltage
source.


People should realise you belong to the school of
"if it measures OK it'll sound better" school.
Plenty of ppl have had experiences with you beaut measuring gear
that sounds wrong.
Almost none of us feel compelled to go buy a Behringer after what you said,
But I have provided the URL if anyone is tempted to try,
so that they may find out for themselves.

Patrick Turner.







--
Trevor Wilson
www.rageaudio.com.au

On Mon, 30 May 2005 21:23:53 -0400, Bob wrote:

On Mon, 30 May 2005 09:30:19 GMT, Patrick Turner
wrote:

Last Saturday I spent some time with one of my clients to assist him
with his sound system, where the speakers consist of some quite old
Altec cast aluminium horns and large ported boxes with 15" woofers..
He is biamping the above, but will be triamping reflex bass speakers and
mid and
treble horn speakers.

Patrick Turner.



I have an old spk system like that, I'd be interested in hearing how you
equalize the horn response...

I think Altek used to have a crossover with mid and treble controls on it...

My system uses a horn tweeter for the highs, xover around 10,000Hz.

Bob, you should Google for Hiraga crossover circuit. It was published
in Sound Practices way back (article by John Stronczer (sp?), IIRC),
and should be found online somewhere.

I have an old pair of Altec A5's which I built this crossover for, and
they sound great with jbl 2404 tweets added on above 8kHz. It
completely tames the midrange horns.

If you can't find the Hiraga article, post back. I think I have the
pdf file around somewhere but won't have time to look for a few days.

-Peter

Peter McMullin wrote:

On Mon, 30 May 2005 21:23:53 -0400, Bob wrote:

On Mon, 30 May 2005 09:30:19 GMT, Patrick Turner
wrote:

Last Saturday I spent some time with one of my clients to assist him
with his sound system, where the speakers consist of some quite old
Altec cast aluminium horns and large ported boxes with 15" woofers..
He is biamping the above, but will be triamping reflex bass speakers and
mid and
treble horn speakers.

Patrick Turner.



I have an old spk system like that, I'd be interested in hearing how you
equalize the horn response...

I think Altek used to have a crossover with mid and treble controls on it...

My system uses a horn tweeter for the highs, xover around 10,000Hz.

Bob, you should Google for Hiraga crossover circuit. It was published
in Sound Practices way back (article by John Stronczer (sp?), IIRC),
and should be found online somewhere.

I have an old pair of Altec A5's which I built this crossover for, and
they sound great with jbl 2404 tweets added on above 8kHz. It
completely tames the midrange horns.

If you can't find the Hiraga article, post back. I think I have the
pdf file around somewhere but won't have time to look for a few days.

-Peter

www.soundpractices.com/images/HiragaA5.pdf

This what you mean?

Patrick Turner.

"Patrick Turner" wrote in message
...


Trevor Wilson wrote:

"Patrick Turner" wrote in message
...


Trevor Wilson wrote:

"Patrick Turner" wrote in message
...

He still has the issue of the active crossover in series between
preamp
and
power amps, and it can colour or ruin the tube
sound, and this unit is an SS opamp based contraption .....

**Please explain how this is possible.

It would be a waste of time to discuss whether SS is any better than
tubes.
PPL here already know the answers.

What I said was "it can ruin..."

**How? Be precise in your answer please.


Maybe it does, maybe it don't, heck, I have not measured the unit.

**Then why make such an inane comment. I recently employed a cheap,
digital
Behringer crossover in a system. It's noise, distortion and frequency
response figures are well beyond the ability of any human to detect. It's
figures (and therefore, it's sound quality) are far better than any SET
product.

You are another one who doesn't belong in this news group.

**Your constant refusal to answer direct and unequivocal questions is duly
noted.



The last time you had any real interest in constructing something with a
tube in
it was
maybe 30 years ago.

**Your constant refusal to answer direct and unequivocal questions is duly
noted.



What I said to Pinkerton, otherwise well known as ""Oinkerton"",
applies to YOU, because he became like the man who insists on selling pork
in a
synagogue,
ie, he tried to tell us to give up our tubes and go squalid state.

**Your constant refusal to answer direct and unequivocal questions is duly
noted. If you imagine that solid state is so bad, then I suggest you do the
following:

* Cease building solid state amplifiers.
* Dispose of ALL digital sources.

I'll wait while you do this. Let me know when you're ready.


Since "Oinky" has so very little to contribute to
the understanding of tube craft and the use of tubes in audio systems,
he didn't last here as a permanent fixture, and nor will you, should you
wish to
unjustafiably
**** on all of us over the issue of SET amps, which I may add can make
excellent
amplifiers,
a fact that has yet to register in your brain.

**There is nothing that can be done with a SET amp that cannot be done with
a push pull system. Except distortion, of course. PP provides an automatic
reduction in even order distortion. But you already knew that. However, that
disguises the actual arguemtn we have right now: ELECTRONIC CROSSOVERS. The
best, least expensive, most convenient method, is to use something like the
Behringer 24/96 crossover. It will introduce INAUDIBLE levels of problems.


People can feel free to go through the archives for aus.hi-fi where at
hi-fi
where you have a dismal record at dismissing legitimate amplifier systems.

**What "legitemate amplifier systems" would they be? More interestingly, Mr
Turner, why is that when I begin discussing EQUIPMENT and the most logical,
rational method of acheiving a particular result, do YOU begin to insult and
demean me? Why is that, Mr Turner? Are you afraid of discussing the facts?
As an old soccer player, I clearly recall my dear old dad's words: "Play the
ball, son, not the man." The same goes for arguments. Discuss the EQUIPMENT,
not the person discussing that equipment.



So should you wish to become to be seen as another un-informative and
destructive fool,
keep blathering the way you are about SET amps, you have the right,
but you will loose any slight respect you have here.

**If people refuse to listen to logic and reason, that is their problem.


As for the Behringer, who knows, maybe its better or worse than anything
else.
You would have to work harder to convince us we cannot do without one.
There is one at

http://www.behringer.com/CX3400/index.cfm?lang=ENG

Its aud $300.00

And a more expensive looking one at

http://www.behringer.com/DCX2496/index.cfm?lang=ENG

The pdf spec sheet of the CX3400 gives thd 0.04%, which is more than
what a tubed active crossover using SET topologies could easily achieve.

**Fortunately, there is MUCH more than just THD. The Behringer offers a
convenience and accuracy that regular analogue crossover designers (tube or
SS) could only dream of.



But it is another gadget in the signal path.
It should be more benign than a set of passive normal crossovers,
because I am told it has none of the phase shift with LCRs or the RC
networks
used
in feedback networks around opamps.
I am not all that sure that the phase shift is all that much trouble,
if the audio amateur understands how to allow for it.
When i rebuild crossovers for normal speakers which I am called to
re-engineer professionally, It is a PITA to have to keep phase shift in
mind
at all times, lest signals cancel each other or add in ways to upset the
response.
Unfortunately, speakers also display level responses that are rarely
ever near flat as we might wish, and a theoretical choice of crossover
point
between two speakers may not work in practice, and the speakers must be
measured to verify how you really want to set up the crossovers,
so that a reasonably flat response is achieved. Not only must the
crossover
serve to
divide F to various drivers but they must compensate for varying acoustic
output in their bands, and a theortical Xover rarely is ever one that
works exactly as intended in practice without some trimming.

An absense of phase shift in a crossover would be a blessing,
but its not entirely necessary, and any recorded signal has a different
phase
print than the live performance,
so phase shift is always going to be with us, and one link in the audio
chain
with no phase shift
won't be a cure all.

For analog Xovers I'd rather have a simple tube based active crossover
for
bi/triamping.
The only problem with such like is the inflexibilty.
One has to be sure about levels and poles and speaker selections and level
compensations because it is
hard to make a change and still keep the system optimal if the F poles are
determined by
soldering in various capacitors or resistors.
I'd also maybe prefer a passive LCR crossover, in other words, something
with a minimal number of components, and a bare minimum of phase shift,
requiring nothing more than a low Ra triode CF to drive it, since
to get basic roll-off attenuation rates, the signal source must be a
voltage
source.


People should realise you belong to the school of
"if it measures OK it'll sound better" school.

**Untrue. I belong to the "if it measures like crap, it will sound like
crap" school. BIG difference. SET amps measure like crap.


Plenty of ppl have had experiences with you beaut measuring gear
that sounds wrong.

**Indeed. However, there are some fundamental truths in life. If it measures
like crap, it will be crap.

Almost none of us feel compelled to go buy a Behringer after what you
said,
But I have provided the URL if anyone is tempted to try,
so that they may find out for themselves.

**No one said that all people are smart.


--
Trevor Wilson
www.rageaudio.com.au

Trevor Wilson wrote:


**What "legitemate amplifier systems" would they be? More interestingly, Mr
Turner, why is that when I begin discussing EQUIPMENT and the most logical,
rational method of acheiving a particular result, do YOU begin to insult and
demean me? Why is that, Mr Turner? Are you afraid of discussing the facts?
As an old soccer player, I clearly recall my dear old dad's words: "Play the
ball, son, not the man." The same goes for arguments. Discuss the EQUIPMENT,
not the person discussing that equipment.


Its all been discussed before, and I don't have time to REPEAT AD NAUSEUM
the same old boring discussions re SS vs tubes, etc, with you, yet again.

You come to the group to **** on anyone using an SET amplifier,
so don't whinge about the flack you will gert from me.

Patrick Turner.

On Wed, 01 Jun 2005 11:48:22 -0400, Peter McMullin wrote:

On Mon, 30 May 2005 21:23:53 -0400, Bob wrote:

On Mon, 30 May 2005 09:30:19 GMT, Patrick Turner
wrote:

Last Saturday I spent some time with one of my clients to assist him
with his sound system, where the speakers consist of some quite old
Altec cast aluminium horns and large ported boxes with 15" woofers..
He is biamping the above, but will be triamping reflex bass speakers and
mid and
treble horn speakers.

Patrick Turner.



I have an old spk system like that, I'd be interested in hearing how you
equalize the horn response...

I think Altek used to have a crossover with mid and treble controls on it...

My system uses a horn tweeter for the highs, xover around 10,000Hz.

Bob, you should Google for Hiraga crossover circuit. It was published
in Sound Practices way back (article by John Stronczer (sp?), IIRC),
and should be found online somewhere.

I have an old pair of Altec A5's which I built this crossover for, and
they sound great with jbl 2404 tweets added on above 8kHz. It
completely tames the midrange horns.

If you can't find the Hiraga article, post back. I think I have the
pdf file around somewhere but won't have time to look for a few days.

-Peter

OK I got it... would have to modify it for my horns since they crossover at
1200Hz... Would also like to put a level control...

Bob wrote:

On Wed, 01 Jun 2005 11:48:22 -0400, Peter McMullin wrote:

On Mon, 30 May 2005 21:23:53 -0400, Bob wrote:

On Mon, 30 May 2005 09:30:19 GMT, Patrick Turner
wrote:

Last Saturday I spent some time with one of my clients to assist him
with his sound system, where the speakers consist of some quite old
Altec cast aluminium horns and large ported boxes with 15" woofers..
He is biamping the above, but will be triamping reflex bass speakers and
mid and
treble horn speakers.

Patrick Turner.



I have an old spk system like that, I'd be interested in hearing how you
equalize the horn response...

I think Altek used to have a crossover with mid and treble controls on it...

My system uses a horn tweeter for the highs, xover around 10,000Hz.

Bob, you should Google for Hiraga crossover circuit. It was published
in Sound Practices way back (article by John Stronczer (sp?), IIRC),
and should be found online somewhere.

I have an old pair of Altec A5's which I built this crossover for, and
they sound great with jbl 2404 tweets added on above 8kHz. It
completely tames the midrange horns.

If you can't find the Hiraga article, post back. I think I have the
pdf file around somewhere but won't have time to look for a few days.

-Peter

OK I got it... would have to modify it for my horns since they crossover at
1200Hz... Would also like to put a level control...

Its tricky doing level controls for speakers.
A switched type that makes sure the R load of the crossover
LCR elements remains constant is favourable, thus the pole of the filters and the
attenuation slopes
stay constant. With domestic horn speakers the power is tiny,
so a good quality wafer type switch with 5 watt WW resistors may do ok,
and you may need a 2 pole x 5 position switch; something NOS
may be ok. The cheap Taiwanese multi rotary switches are crap.
Farnell sell some nice rotary switches suitable for flea power horns.

But getting levels right and soldering in fixed R is far better.

Patrick Turner.

"Patrick Turner" wrote in message
...


Trevor Wilson wrote:


**What "legitemate amplifier systems" would they be? More interestingly,
Mr
Turner, why is that when I begin discussing EQUIPMENT and the most
logical,
rational method of acheiving a particular result, do YOU begin to insult
and
demean me? Why is that, Mr Turner? Are you afraid of discussing the
facts?
As an old soccer player, I clearly recall my dear old dad's words: "Play
the
ball, son, not the man." The same goes for arguments. Discuss the
EQUIPMENT,
not the person discussing that equipment.


Its all been discussed before, and I don't have time to REPEAT AD NAUSEUM
the same old boring discussions re SS vs tubes, etc, with you, yet again.

**I note your inability to discuss actual facts. Instead, you prefer to
(attempt) slander me. Good luck. I'm not discussing tubes vs. SS. I am
simply stating that the best, least expensive, lowest distortion method of
implementing an electronic crossover, is to use something like the Behringer
24/96 crossover. It is inexpensive, offer no audible intrusion into any
system, easy to use, VERY accurate and VERY flexible. To duplicate the
Behringer with tubes (if it were possible) would require a small building
full of stuff.


You come to the group to **** on anyone using an SET amplifier,
so don't whinge about the flack you will gert from me.

**Wrong. I just tell the truth. Nothing more, nothing less. I do not comment
on the people who choose to use SET amps. I do, however, comment on SET
amps. Can you see that? Do you not understand that PP confers and automatic
reduction in distortion? I thought you knew a little about amplifier design.
It seems not. Go read your RDH and tell me where it states that PP designs
are in any way inferior to SET designs. I'll wait.

I'll also wait for you to answer my questions. I expect to wait a long time,
since you seem very reluctant to stay on topic, preferring, instead, to
slander anyone who challenges your narrow view.


--
Trevor Wilson
www.rageaudio.com.au

On Thu, 02 Jun 2005 04:25:50 GMT, "Trevor Wilson"
wrote:

I do, however, comment on SET
amps. Can you see that? Do you not understand that

Folks attempt SET designs in an effort to attack the issue of
monotonicity. The tradeoffs are steep and expensive, but they
still make the attempt. Those who haven't investigated the issue
in depth might easily feel slighted somehow. Whatever.

Chris Hornbeck

I'll also wait for you to answer my questions. I expect to wait a long time,
since you seem very reluctant to stay on topic, preferring, instead, to
slander anyone who challenges your narrow view.

You don't learn, do you?

You will never succeed in bullying me one way or the other.

So have a nice long wait, I will not be answering the questions you ask.

You can't dodge the "slander" from here. Slandering others is what you do
everytime you
refer to SET amps.

Patrick Turner.





--
Trevor Wilson
www.rageaudio.com.au

On Thu, 02 Jun 2005 03:38:31 GMT, Patrick Turner
wrote:



Bob wrote:

On Wed, 01 Jun 2005 11:48:22 -0400, Peter McMullin wrote:

On Mon, 30 May 2005 21:23:53 -0400, Bob wrote:

On Mon, 30 May 2005 09:30:19 GMT, Patrick Turner
wrote:

Last Saturday I spent some time with one of my clients to assist him
with his sound system, where the speakers consist of some quite old
Altec cast aluminium horns and large ported boxes with 15" woofers..
He is biamping the above, but will be triamping reflex bass speakers and
mid and
treble horn speakers.

Patrick Turner.



I have an old spk system like that, I'd be interested in hearing how you
equalize the horn response...

I think Altek used to have a crossover with mid and treble controls on it...

My system uses a horn tweeter for the highs, xover around 10,000Hz.

Bob, you should Google for Hiraga crossover circuit. It was published
in Sound Practices way back (article by John Stronczer (sp?), IIRC),
and should be found online somewhere.

I have an old pair of Altec A5's which I built this crossover for, and
they sound great with jbl 2404 tweets added on above 8kHz. It
completely tames the midrange horns.

If you can't find the Hiraga article, post back. I think I have the
pdf file around somewhere but won't have time to look for a few days.

-Peter

OK I got it... would have to modify it for my horns since they crossover at
1200Hz... Would also like to put a level control...

Its tricky doing level controls for speakers.
A switched type that makes sure the R load of the crossover
LCR elements remains constant is favourable, thus the pole of the filters and the
attenuation slopes
stay constant. With domestic horn speakers the power is tiny,
so a good quality wafer type switch with 5 watt WW resistors may do ok,
and you may need a 2 pole x 5 position switch; something NOS
may be ok. The cheap Taiwanese multi rotary switches are crap.
Farnell sell some nice rotary switches suitable for flea power horns.

But getting levels right and soldering in fixed R is far better.

Patrick Turner.


I guess I could set up some kind of T pad, I have some old 10 watt 8 ohm L
controls, and use it to select the best 'sound' from the system... and then put
fixed resistors... I don't have too much hope for this ancient system though,
it's basically a low power rock and roll PA! Back to the 70s!

Patrick Turner wrote:
Last Saturday I spent some time with one of my clients to assist him
with his sound system, where the speakers consist of some quite old
Altec cast aluminium horns and large ported boxes with 15" woofers..
He is biamping the above, but will be triamping reflex bass speakers and
mid and
treble horn speakers.
A few weeks ago we tested the horns to find they gave very different
response and sensitivity contours, thus indicating one or both had
stuffed diapragms.
The result was very honky lack lustre sound.
Last Saturday we replaced the drivers with a NOS pair he found,
and each horn then gave the same nice arched bandpass response using
the same input voltage of pink noise noise signal and same mic at 3
metres away
The curves of L and R were within a dB of each other.
The test confirmed that pink noise is a very useful way of measuring
response.

I set up the pink noise test signal about as loud
as music on the horns and measured
0.04 vrms of signal.
This is 0.2 milliwatt.
The horns are 105 dB/W/M efficient, and 0.2mW give about 68dBSPL at a
metre,
maybe 66 db at 3M in a room, but plenty loud enough to overcome
street noise outside, and other house noises, and quite measurable by my
test mic
with negligible distortions.
An SE 300B is used for these midrange horns which are set for 500Hz
crossover from the bass,
and which go to about 7 kHz.
He has McIntosh 60 watt mono PP amps for the bass 15" which measured
far less sensitive than the mid horns.
He will be using 2A3 amps I am building for his proposed tweeter horns
which cover from 7kHz upwards.
I doubt he'd ever use more than 1/2 a watt total, for all 6 speakers in
the system.

He'd be quite OK with just the 300B amps for all
the speakers with passive Xovers.
We are considering placing capacitors in series with the mid and treble
amps
and the horns just in case a burst of LF hum accidently takes out one of
the horn
speaker voice coils.

So even though one aims to remove things in series
with speakers, one still has to protect them

He still has the issue of the active crossover in series between preamp
and
power amps, and it can colour or ruin the tube
sound, and this unit is an SS opamp based contraption .....

When i get the tweeter amps built, we will be switching to use of an ARC
3 way crossover,
and this old thing looks like it was made before ARC went all strange
and designed all their
circuits with 15dB too many parts. It just has 6 twin triodes inside,
and some simple
looking circuit boards, on which the R&C parts can be changed to suit
the wanted
crossover points.

This guy would be quite lost trying to figure it out on his own.
He's the director of a trade commission, and a complete gentleman,
but not a man with any experience of comprehending the physics
of what he's doing.
If you don't know how to figure all this stuff out, its quite
understandable,
maybe only 15% of dudes at r.a.t have any idea at all,
and to make sure one has it right takes knowing someone you could trust
to fiddle with your speakers with the right gear.

We had a listen to the system which we now know has at least 4 good
speakers,
and the sound was a vast improvement over the honky sound we heard
a few weeks back.
And all this despite the top end completely missing.
In fact I could say his system shows signs of changing my prejudice
that
all horns tend to suck; here we have a pair that were doing rather well
with
music.

He still has a long way to go before gets the best sound possible.
His room has a timber floor, and the usual hard plastered walls and
ceiling,
so the reverbrations are seriously affecting his sound, but when he gets
a large thick
rug and completes some shelves for his vinyl collections he will hear
much better sound.

Patrick Turner.







The alumninum Altec horns all require extensive external damping, they
ring like bells. I like to do some internal things too - you can discern
that on your own... :- )

Lose the Audio Research Xover - it's oddly grainy. Maybe ok for a LP to
the woofer.

Go with the xovers built into the amps.

Use a stepped atten at the inputs of the amps to set the relative levels.

I'd switch the guy to a larger (largest you can find) Altec Multi Cell
or a single cell, of the tractrix or similar expansion if you can.


_-_-bear

BEAR wrote:

Patrick Turner wrote:
Last Saturday I spent some time with one of my clients to assist him
with his sound system, where the speakers consist of some quite old
Altec cast aluminium horns and large ported boxes with 15" woofers..
He is biamping the above, but will be triamping reflex bass speakers and
mid and
treble horn speakers.
A few weeks ago we tested the horns to find they gave very different
response and sensitivity contours, thus indicating one or both had
stuffed diapragms.
The result was very honky lack lustre sound.
Last Saturday we replaced the drivers with a NOS pair he found,
and each horn then gave the same nice arched bandpass response using
the same input voltage of pink noise noise signal and same mic at 3
metres away
The curves of L and R were within a dB of each other.
The test confirmed that pink noise is a very useful way of measuring
response.

I set up the pink noise test signal about as loud
as music on the horns and measured
0.04 vrms of signal.
This is 0.2 milliwatt.
The horns are 105 dB/W/M efficient, and 0.2mW give about 68dBSPL at a
metre,
maybe 66 db at 3M in a room, but plenty loud enough to overcome
street noise outside, and other house noises, and quite measurable by my
test mic
with negligible distortions.
An SE 300B is used for these midrange horns which are set for 500Hz
crossover from the bass,
and which go to about 7 kHz.
He has McIntosh 60 watt mono PP amps for the bass 15" which measured
far less sensitive than the mid horns.
He will be using 2A3 amps I am building for his proposed tweeter horns
which cover from 7kHz upwards.
I doubt he'd ever use more than 1/2 a watt total, for all 6 speakers in
the system.

He'd be quite OK with just the 300B amps for all
the speakers with passive Xovers.
We are considering placing capacitors in series with the mid and treble
amps
and the horns just in case a burst of LF hum accidently takes out one of
the horn
speaker voice coils.

So even though one aims to remove things in series
with speakers, one still has to protect them

He still has the issue of the active crossover in series between preamp
and
power amps, and it can colour or ruin the tube
sound, and this unit is an SS opamp based contraption .....

When i get the tweeter amps built, we will be switching to use of an ARC
3 way crossover,
and this old thing looks like it was made before ARC went all strange
and designed all their
circuits with 15dB too many parts. It just has 6 twin triodes inside,
and some simple
looking circuit boards, on which the R&C parts can be changed to suit
the wanted
crossover points.

This guy would be quite lost trying to figure it out on his own.
He's the director of a trade commission, and a complete gentleman,
but not a man with any experience of comprehending the physics
of what he's doing.
If you don't know how to figure all this stuff out, its quite
understandable,
maybe only 15% of dudes at r.a.t have any idea at all,
and to make sure one has it right takes knowing someone you could trust
to fiddle with your speakers with the right gear.

We had a listen to the system which we now know has at least 4 good
speakers,
and the sound was a vast improvement over the honky sound we heard
a few weeks back.
And all this despite the top end completely missing.
In fact I could say his system shows signs of changing my prejudice
that
all horns tend to suck; here we have a pair that were doing rather well
with
music.

He still has a long way to go before gets the best sound possible.
His room has a timber floor, and the usual hard plastered walls and
ceiling,
so the reverbrations are seriously affecting his sound, but when he gets
a large thick
rug and completes some shelves for his vinyl collections he will hear
much better sound.

Patrick Turner.






The alumninum Altec horns all require extensive external damping, they
ring like bells. I like to do some internal things too - you can discern
that on your own... :- )

Indeed, and much work still has to be done to damp the Al horns.



Lose the Audio Research Xover - it's oddly grainy. Maybe ok for a LP to
the woofer.

We'll see eh.



Go with the xovers built into the amps.

Use a stepped atten at the inputs of the amps to set the relative levels.

We have already got enough damn attenuators.....



I'd switch the guy to a larger (largest you can find) Altec Multi Cell
or a single cell, of the tractrix or similar expansion if you can.

Switching the man isn't easy.

Finding alternative horns isn't easy either.

Nothing is easy, especially when the owner is totally unaware
of any electronic principles.

Patrick Turner.



_-_-bear