Reply
 
Thread Tools Display Modes
  #1   Report Post  
Posted to rec.audio.pro
Boris[_2_] Boris[_2_] is offline
external usenet poster
 
Posts: 15
Default Speaker Impedence ?

Hi,

If there is a better newsgroup for this question, please let me know.

I want to hook up some old equipment I bought back in 1994. It's an
Onkyo six cd changer, and an Onkyo amp/receiver. It's from the old
Circuit City days. They were mid-range comsumer electronic components
at the time. I can give model numbers if needed.

The amp/receiver will power two sets of speakers, and has two buttons on
the front, A and B to enable one or both sets. The rear of the
amp/receiver has terminals for speakers A and B. Under the row of
terminals, there is a warning:

Caution
Speaker A or B: 4 ohms
Speaker A and B: 8 ohms

I have been using a set of 6 ohm speakers and they work on either A or
B, but I'd like to do things right.

Should I get a set of 4 ohm speakers?
Is the 8 ohm warning only necessary if I have both sets of speakers
enabled, or is it relevant even if I have two sets connected, but only
one enalbled at a time.

I have been to Wikipedia, and googled all of this, but I'd like to hear
from you.

Thanks.
  #2   Report Post  
Posted to rec.audio.pro
[email protected] thekmanrocks@gmail.com is offline
external usenet poster
 
Posts: 1,742
Default Speaker Impedence ?

Boris: With impedance, go over, but
never under! I don't know any of
the math associated with impedance,
but if your receiver say 4ohms that
is just the minimum you never go
below. You can drive 12ohm speakers
with it, just might not be loud enough
for you.

My receiver can handle 8-16ohm
speakers(It's a 22 year old JVC).
I can run 8ohm and up with it,
never down.
  #3   Report Post  
Posted to rec.audio.pro
Scott Dorsey Scott Dorsey is offline
external usenet poster
 
Posts: 16,853
Default Speaker Impedence ?

Boris wrote:

If there is a better newsgroup for this question, please let me know.


That would be rec.audio.tech.

The amp/receiver will power two sets of speakers, and has two buttons on
the front, A and B to enable one or both sets. The rear of the
amp/receiver has terminals for speakers A and B. Under the row of
terminals, there is a warning:

Caution
Speaker A or B: 4 ohms
Speaker A and B: 8 ohms


These are minimum ratings. If you use just one set of speakers, 4 ohm
speakers are fine. If you use both at the same time, you need 8 ohm
or higher.

I have been using a set of 6 ohm speakers and they work on either A or
B, but I'd like to do things right.


That's fine, just don't use two sets of 6 ohm speakers.

Should I get a set of 4 ohm speakers?


Buy speakers that sound good, don't worry about the impedance. Worry about
how they sound.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."
  #6   Report Post  
Posted to rec.audio.pro
[email protected] thekmanrocks@gmail.com is offline
external usenet poster
 
Posts: 1,742
Default Speaker Impedence ?

Scott Dorsey wrote:

"That's fine, just don't use two sets of 6 ohm speakers"

Why not? They're above the minimum
stated on the back of his receiver.



"Buy speakers that sound good, don't worry about the impedance. Â*Worry about
how they sound"

Typical 'engineer' statement. Fine:

Remove all impedance specs from
the backs of speakers, receivers, and
amplifiers. While we're at it, remove
signal presence and OL single LED
indicators and all the meters from
DAWs and mixing consoles.

Remove the specifications page
from the website and from the operators
manuals. It doesn't matter right?
Whether to run balanced or unbalanced
lines, whether this component is over
heating, that one is distorting, or the
other one is clipping. As long as it
"sounds good" "Use your ears"!!!

Ave Maria purissmo...
  #7   Report Post  
Posted to rec.audio.pro
[email protected] thekmanrocks@gmail.com is offline
external usenet poster
 
Posts: 1,742
Default Speaker Impedence ?

Scott Dorsey wrote:

"That's fine, just don't use two sets of 6 ohm speakers"

Why not? They're above the minimum
stated on the back of his receiver.



"Buy speakers that sound good, don't worry about the impedance. Â*Worry about
how they sound"

Typical 'engineer' statement. Fine:

Remove all impedance specs from
the backs of speakers, receivers, and
amplifiers. While we're at it, remove
signal presence and OL single LED
indicators and all the meters from
DAWs and mixing consoles.

Remove the specifications page
from the website and from the operators
manuals. It doesn't matter right?
Whether to run balanced or unbalanced
lines, whether this component is over
heating, that one is distorting, or the
other one is clipping. As long as it
"sounds good" "Use your ears"!!!

Ave Maria purissmo...
  #8   Report Post  
Posted to rec.audio.pro
[email protected] thekmanrocks@gmail.com is offline
external usenet poster
 
Posts: 1,742
Default Speaker Impedence ?

Scott Dorsey wrote:

"That's fine, just don't use two sets of 6 ohm speakers"

Why not? They're above the minimum
stated on the back of his receiver.



"Buy speakers that sound good, don't worry about the impedance. Â*Worry about
how they sound"

Typical 'engineer' statement. Fine:

Remove all impedance specs from
the backs of speakers, receivers, and
amplifiers. While we're at it, remove
signal presence and OL single LED
indicators and all the meters from
DAWs and mixing consoles.

Remove the specifications page
from the website and from the operators
manuals. It doesn't matter right?
Whether to run balanced or unbalanced
lines, whether this component is over
heating, that one is distorting, or the
other one is clipping. As long as it
"sounds good" "Use your ears"!!!

Ave Maria purissmo...
  #9   Report Post  
Posted to rec.audio.pro
Scott Dorsey Scott Dorsey is offline
external usenet poster
 
Posts: 16,853
Default Speaker Impedence ?

Boris wrote:
(Scott Dorsey) wrote in

These are minimum ratings. If you use just one set of speakers, 4 ohm
speakers are fine. If you use both at the same time, you need 8 ohm
or higher.


When you say 'at the same time', could I have two sets of 4 ohm speakers
connected, but only play through one set,say set A enabled, at a time?
Or, is just having two sets of 4 ohm speakers connected at the same
time, even if only one set is playing, incorrect?


If only one set is selected, it's fine. The problem is that sooner or
later, if the buttons allow both sets to be selected, someone will do that.
You can put a big sign on it saying not to do that, but someday it will
happen and then the output stage will fail.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."
  #10   Report Post  
Posted to rec.audio.pro
Mike Rivers[_2_] Mike Rivers[_2_] is offline
external usenet poster
 
Posts: 2,190
Default Speaker Impedence ?

On 4/28/2017 8:57 AM, Boris wrote:
The amp/receiver will power two sets of speakers, and has two buttons on
the front, A and B to enable one or both sets. The rear of the
amp/receiver has terminals for speakers A and B. Under the row of
terminals, there is a warning:

Caution
Speaker A or B: 4 ohms
Speaker A and B: 8 ohms

I have been using a set of 6 ohm speakers and they work on either A or
B, but I'd like to do things right.

Should I get a set of 4 ohm speakers?


Nope, not unless you get some that will be a significant improvement
over what you already have, for reasons other than impedance.

What they're trying to tell you here is that the amplifier is perfectly
comfortable driving a 4 ohm load (which would be two 8 ohm speakers in
parallel) but it wouldn't be happy driving a 2 ohm load (two 4 ohm
speakers in parallel).

Speaker impedance is mostly nominal anyway, and can vary a great amount
with frequency. Also, speaker efficiency also varies a lot. This means
that for an average power of 1 watt going to the speaker (whatever
voltage it takes for a given impedance) not all speakers will play at
the same loudness.

Is the 8 ohm warning only necessary if I have both sets of speakers
enabled, or is it relevant even if I have two sets connected, but only
one enalbled at a time.


If you have two sets of speakers connected and use only one set at a
time, that's the same as having only one set of speakers connected. So
you could connect two sets of 4 ohm speakers and use them one at a time
with no worries. In truth, you could probably use them both together and
not cause any trouble unless you're running them very loud.

--
"Today's production equipment is IT based and cannot be operated without
a passing knowledge of computing, although it seems that it can be
operated without a passing knowledge of audio" - John Watkinson

Drop by http://mikeriversaudio.wordpress.com now and then


  #11   Report Post  
Posted to rec.audio.pro
Mike Rivers[_2_] Mike Rivers[_2_] is offline
external usenet poster
 
Posts: 2,190
Default Speaker Impedence ?

On 4/28/2017 11:51 AM, Boris wrote:
Wish I had kept some of my old tube equipment from the mid-70s. But, the
capacitors may be dried out by now.


It can be fixed. But tube amplifiers are different from solid state
amplifiers in many ways. A solid state amplifier has a very low output
impedance, which makes the voltage that the speaker sees pretty much the
same for an 8 ohm or a 4 ohm speaker. But for the same applied voltage,
the 4 ohm speaker will draw twice as much current, and that's what makes
the amplifier sweat.

A tube amplifier has an output transformer which has a higher source
impedance, and they make an attempt to match the source (transformer
output) impedance to the load impedance by putting a couple of taps on
the transformer secondary. For a given input signal level, the 4 ohm tap
provides a lower voltage than the 8 ohm tap. You get maximum power
transferred from the amplifier to the speaker when the load and source
impedances are equal.

The other thing about tube amplifiers is that it's not a good idea to
run them with no load on the output transformer. It's not always the
case, but some times the unloaded voltage can get so high that the
transformer will arc between turns of the coil and could be damaged
expensively.

--
"Today's production equipment is IT based and cannot be operated without
a passing knowledge of computing, although it seems that it can be
operated without a passing knowledge of audio" - John Watkinson

Drop by http://mikeriversaudio.wordpress.com now and then
  #12   Report Post  
Posted to rec.audio.pro
geoff geoff is offline
external usenet poster
 
Posts: 1,481
Default Speaker Impedence ?

On 29/04/2017 3:57 a.m., Boris wrote:
Hi,

If there is a better newsgroup for this question, please let me know.

I want to hook up some old equipment I bought back in 1994. It's an
Onkyo six cd changer, and an Onkyo amp/receiver. It's from the old
Circuit City days. They were mid-range comsumer electronic components
at the time. I can give model numbers if needed.

The amp/receiver will power two sets of speakers, and has two buttons on
the front, A and B to enable one or both sets. The rear of the
amp/receiver has terminals for speakers A and B. Under the row of
terminals, there is a warning:

Caution
Speaker A or B: 4 ohms
Speaker A and B: 8 ohms

I have been using a set of 6 ohm speakers and they work on either A or
B, but I'd like to do things right.

Should I get a set of 4 ohm speakers?
Is the 8 ohm warning only necessary if I have both sets of speakers
enabled, or is it relevant even if I have two sets connected, but only
one enalbled at a time.

I have been to Wikipedia, and googled all of this, but I'd like to hear
from you.

Thanks.


Should be fine for one pair of 6 ohm speakers on A or B.

Looks like the limiting factor is 4 ohm minimum impedance, which would
be 3 if you had two pairs attached at the same time, as it could seem to
be one stereo amp with simple switching on the output, or a 4-channel
amp with a power-supply limitation to driving a total total of 2 x 4 ohms.


geoff

  #13   Report Post  
Posted to rec.audio.pro
geoff geoff is offline
external usenet poster
 
Posts: 1,481
Default Speaker Impedence ?

On 29/04/2017 4:14 a.m., wrote:
Boris: With impedance, go over, but
never under! I don't know any of
the math associated with impedance,

It is fairly simple arithmetic. Google it.

geoff
  #14   Report Post  
Posted to rec.audio.pro
geoff geoff is offline
external usenet poster
 
Posts: 1,481
Default Speaker Impedence ?

On 29/04/2017 7:14 a.m., Boris wrote:
When you say 'at the same time', could I have two sets of 4 ohm speakers
connected, but only play through one set,say set A enabled, at a time?


Yes, but sounds like a recipe for disaster as a 2 ohm load may be momentarily applied at the wrong moment ...

geoff

  #17   Report Post  
Posted to rec.audio.pro
[email protected] thekmanrocks@gmail.com is offline
external usenet poster
 
Posts: 1,742
Default Speaker Impedence ?

geoff wrote: "
I hope you were joking (not always apparent).

Sounds great, still sounds great, oh it's stopped completely. Too late.

geoff "


I was stone-cold serious geoff.

Scott Dorsey and Ian Shepard are
two of the biggest "use your ears"/
"whatever sounds best" advocates
in and out of rec.audio.pro. So I
meant it: Why label the backs of
amps and speakers with impedance
ranges, have meters on equipment,
or have specification sheets, since
specs "don't matter" according to
those two? Take altimeters out of
planes and speedometers out of
cars & trucks while we're at it -
just fly as high as feels comfortable,
and go with the flow in traffic!
  #18   Report Post  
Posted to rec.audio.pro
Phil Allison[_4_] Phil Allison[_4_] is offline
external usenet poster
 
Posts: 499
Default Speaker Impedence ?

Boris wrote:


Is the 8 ohm warning only necessary if I have both sets of speakers
enabled, or is it relevant even if I have two sets connected, but only
one enalbled at a time.


** The warning is about using a load that has an impedance less than 4 ohms - cos the makers figure the amp is at it's safe limit with that number.

But makers also know that overheating will not occur unless the amp is played to its output power limit - as it might be during a party.

You need to keep both facts in mind.

..... Phil

  #19   Report Post  
Posted to rec.audio.pro
Ron C[_2_] Ron C[_2_] is offline
external usenet poster
 
Posts: 253
Default Speaker Impedence ?

On 4/28/2017 9:38 PM, geoff wrote:
On 29/04/2017 9:59 a.m., wrote:
Scott Dorsey wrote:

"That's fine, just don't use two sets of 6 ohm speakers"

Why not? They're above the minimum
stated on the back of his receiver.



"Buy speakers that sound good, don't worry about the impedance. Worry
about
how they sound"

Typical 'engineer' statement. Fine:

Remove all impedance specs from
the backs of speakers, receivers, and
amplifiers. While we're at it, remove
signal presence and OL single LED
indicators and all the meters from
DAWs and mixing consoles.

Remove the specifications page
from the website and from the operators
manuals. It doesn't matter right?
Whether to run balanced or unbalanced
lines, whether this component is over
heating, that one is distorting, or the
other one is clipping. As long as it
"sounds good" "Use your ears"!!!

Ave Maria purissmo...


It was stupid once. Thrice is stupider.

geoff

I'll give K-Man a tiny bit of credit for having learned
a few things since he started posting here.

However, it seems the world of difference between
consumer gear "specs" and pro gear specs.
[The quality of /prosumer/ specs are a total toss-up.]

When Scott and others here say "use your ears" there
are a lot of unstated assumptions that pro and semi-pro
understand with out the need for a detailed /caveat/ list.

==
Later...
Ron Capik
--

  #20   Report Post  
Posted to rec.audio.pro
None None is offline
external usenet poster
 
Posts: 782
Default Speaker Impedence ?



thekmahhhhh @ dum****.retard.doh wrote in message
...
Scott Dorsey wrote:
Remove all impedance specs from
the backs of speakers, receivers, and
amplifiers. While we're at it, remove
signal presence and OL single LED
indicators and all the meters from
DAWs and mixing consoles.

Remove the specifications page
from the website and from the operators
manuals


And remove your retarded skull from your rectum. Your colon cancer has
spread to your tiny little brain, due to direct physical contact. In
your case, since you dont give a **** what anything actually sounds
like, and your shoe-size IQ won't allow you to use anything resembling
reason, you should just buy whatever the **** appeals to your
grape-sized intellect, and keep a bucket of gasoline handy to douse
the amplifier when it gets to hot.

You should probably just re-wire your entire home electrical system,
guided by random eejits on the net. When the code requires you to do
the arithmetic, just connect your toaster to the bus bars with jumper
cables. LKHSD, BDQNAPDJBF. FCKWAFA!




  #21   Report Post  
Posted to rec.audio.pro
Phil Allison[_4_] Phil Allison[_4_] is offline
external usenet poster
 
Posts: 499
Default Speaker Impedence ?

Mike Rivers wrote:



But tube amplifiers are different from solid state
amplifiers in many ways. A solid state amplifier has a very low output
impedance, which makes the voltage that the speaker sees pretty much the
same for an 8 ohm or a 4 ohm speaker. But for the same applied voltage,
the 4 ohm speaker will draw twice as much current, and that's what makes
the amplifier sweat.


** Typical SS amps for home hi-fi have output impedances around 0.1 ohms.

The speaker lead adds maybe 0.3 ohms to that - so 0.4 ohms all up.


A tube amplifier has an output transformer which has a higher source
impedance, and they make an attempt to match the source (transformer
output) impedance to the load impedance by putting a couple of taps on
the transformer secondary.


** The output impedance of a good quality tube amp is around 0.5 to 1 ohm when used at the 8 ohms setting.

For a given input signal level, the 4 ohm tap provides a lower voltage
than the 8 ohm tap.


** But with 40% more current available.


You get maximum power
transferred from the amplifier to the speaker when the load and source
impedances are equal.



** More precisely, when the two are *matched* - so an 8ohms load on the 8ohm setting and so on.

However, actual speaker impedance varies widely over the audio range so it is only gonna be "matched" in the mid band - around 200 to 500 Hz.



..... Phil

  #23   Report Post  
Posted to rec.audio.pro
[email protected] jjaj1998@netscape.net is offline
external usenet poster
 
Posts: 331
Default Speaker Impedence ?

On Friday, April 28, 2017 at 12:14:51 PM UTC-4, wrote:
Boris: With impedance, go over, but
never under! I don't know any of
the math associated with impedance,
but if your receiver say 4ohms that
is just the minimum you never go
below. You can drive 12ohm speakers
with it, just might not be loud enough
for you.

My receiver can handle 8-16ohm
speakers(It's a 22 year old JVC).
I can run 8ohm and up with it,
never down.


My woofer stopped woofing. I blame it on speaker Impotence.

Jack
  #25   Report Post  
Posted to rec.audio.pro
[email protected] thekmanrocks@gmail.com is offline
external usenet poster
 
Posts: 1,742
Default Speaker Impedence ?

Ron Capik wrote: "I'll give K-Man a tiny bit of credit for having learned
a few things since he started posting here. "

Thanks!



"When Scott and others here say "use your ears" there
are a lot of unstated assumptions that pro and semi-pro
understand with out the need for a detailed /caveat/ list."

Well, we all know about ASSuming, and
one would have to BE one by stating
that documentation and metering are
not important. To them I say: Both
meters and ears matter!


  #26   Report Post  
Posted to rec.audio.pro
Mike Rivers[_2_] Mike Rivers[_2_] is offline
external usenet poster
 
Posts: 2,190
Default Speaker Impedence ?

On 4/29/2017 6:09 AM, geoff wrote:
If anything I would have expected your tweeter to blow.


When they're out of phase, they suck.

--
"Today's production equipment is IT based and cannot be operated without
a passing knowledge of computing, although it seems that it can be
operated without a passing knowledge of audio" - John Watkinson

Drop by http://mikeriversaudio.wordpress.com now and then
  #27   Report Post  
Posted to rec.audio.pro
Scott Dorsey Scott Dorsey is offline
external usenet poster
 
Posts: 16,853
Default Speaker Impedence ?

wrote:
Scott Dorsey and Ian Shepard are
two of the biggest "use your ears"/
"whatever sounds best" advocates
in and out of rec.audio.pro. So I
meant it: Why label the backs of
amps and speakers with impedance
ranges, have meters on equipment,
or have specification sheets, since
specs "don't matter" according to
those two? Take altimeters out of
planes and speedometers out of
cars & trucks while we're at it -
just fly as high as feels comfortable,
and go with the flow in traffic!


If your specification sheet consists only of useless information
like a scalar impedance number (which really bears little connection
to the actual speaker impedance plot), a frequency range without
tolerances (which is utterly meaningless) and speaker power ratings that
are made up by someone in the marketing department, then by all means we
should definitely not have specification sheets.

Because these are not actual specifications, they are not actual measurements,
they are more misleading than helpful.

Making decisions based on such information is not going to do you any good,
it will only give you a false sense of being informed when you are not.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."
  #28   Report Post  
Posted to rec.audio.pro
[email protected] jjaj1998@netscape.net is offline
external usenet poster
 
Posts: 331
Default Speaker Impedence ?

On Friday, April 28, 2017 at 10:40:04 PM UTC-4, Ron C wrote:
On 4/28/2017 9:38 PM, geoff wrote:
On 29/04/2017 9:59 a.m., wrote:
Scott Dorsey wrote:

"That's fine, just don't use two sets of 6 ohm speakers"

Why not? They're above the minimum
stated on the back of his receiver.



"Buy speakers that sound good, don't worry about the impedance. Worry
about
how they sound"

Typical 'engineer' statement. Fine:

Remove all impedance specs from
the backs of speakers, receivers, and
amplifiers. While we're at it, remove
signal presence and OL single LED
indicators and all the meters from
DAWs and mixing consoles.

Remove the specifications page
from the website and from the operators
manuals. It doesn't matter right?
Whether to run balanced or unbalanced
lines, whether this component is over
heating, that one is distorting, or the
other one is clipping. As long as it
"sounds good" "Use your ears"!!!

Ave Maria purissmo...


It was stupid once. Thrice is stupider.

geoff

I'll give K-Man a tiny bit of credit for having learned
a few things since he started posting here.

However, it seems the world of difference between
consumer gear "specs" and pro gear specs.
[The quality of /prosumer/ specs are a total toss-up.]




Feel, so called, audiophiles depend 100% on equipment, hoping it will make the music they like sound better!! You see people making money with HD files, HD CD, HD this and that, just like Pono stuff, but so many don't know HQ audio if it bit them in the arse!

Jack



When Scott and others here say "use your ears" there
are a lot of unstated assumptions that pro and semi-pro
understand with out the need for a detailed /caveat/ list.

==
Later...
Ron Capik
--


  #30   Report Post  
Posted to rec.audio.pro
[email protected] jjaj1998@netscape.net is offline
external usenet poster
 
Posts: 331
Default Speaker Impedence ?

On Saturday, April 29, 2017 at 10:03:03 AM UTC-4, Mike Rivers wrote:
On 4/29/2017 6:09 AM, geoff wrote:
If anything I would have expected your tweeter to blow.


When they're out of phase, they suck.


Watch that use of "phase", you don't want to upset Scott, do you?

Jack :-)


--
"Today's production equipment is IT based and cannot be operated without
a passing knowledge of computing, although it seems that it can be
operated without a passing knowledge of audio" - John Watkinson

Drop by http://mikeriversaudio.wordpress.com now and then




  #31   Report Post  
Posted to rec.audio.pro
John Williamson John Williamson is offline
external usenet poster
 
Posts: 1,753
Default Speaker Impedence ?

On 29/04/2017 14:14, wrote:
Ron Capik wrote: "I'll give K-Man a tiny bit of credit for having learned
a few things since he started posting here. "

Thanks!



"When Scott and others here say "use your ears" there
are a lot of unstated assumptions that pro and semi-pro
understand with out the need for a detailed /caveat/ list."

Well, we all know about ASSuming, and
one would have to BE one by stating
that documentation and metering are
not important. To them I say: Both
meters and ears matter!

When specifying pro gear, meters and ears are both important as the
limits within which it will work to the spec are important, both for its
intended use and its maximum life, bearing in mind that pro gear tends
to be run much closer to its limits than a home audio setup.

With consumer gear, specifications are generally much wider, and quality
is more variable within a run of stuff off the line, and as long as you
are running within its limits, metering and close attention to
impedances isn't all that important since the dawn of direct coupled
transistor amplifiers, which brought an end to the need to match the
output stage and transformer to the speaker impedances. Even the lower
limit of impedance stated by the maker will have a margin built in, so
in the case under consideration here, the amplifier will survive two
sets of 4 ohm speakers in parallel, subject to a possibility of
instability due to power supply overloading, and thermal problems if the
volume is turned up too high, so causing the output transistors to
exceed their safe dissipation levels.

Hence Scott and others will say of consumer gear "Use your ears, and of
it sounds good, that's okay." When they are setting up a session or
building a studio, repeatability is important, so they use meters and
cheat sheets to document the setup, so that the next session is the same
as the current one. For non critical applications, then "Use your ears"
is a good rule for pro gear and setups as well, as long as the original
specification was done correctly.

--
Tciao for Now!

John.
  #32   Report Post  
Posted to rec.audio.pro
[email protected] jjaj1998@netscape.net is offline
external usenet poster
 
Posts: 331
Default Speaker Impedence ?

On Saturday, April 29, 2017 at 2:24:56 PM UTC-4, John Williamson wrote:
On 29/04/2017 14:14, wrote:
Ron Capik wrote: "I'll give K-Man a tiny bit of credit for having learned
a few things since he started posting here. "

Thanks!



"When Scott and others here say "use your ears" there
are a lot of unstated assumptions that pro and semi-pro
understand with out the need for a detailed /caveat/ list."

Well, we all know about ASSuming, and
one would have to BE one by stating
that documentation and metering are
not important. To them I say: Both
meters and ears matter!

When specifying pro gear, meters and ears are both important as the
limits within which it will work to the spec are important, both for its
intended use and its maximum life, bearing in mind that pro gear tends
to be run much closer to its limits than a home audio setup.

With consumer gear, specifications are generally much wider, and quality
is more variable within a run of stuff off the line, and as long as you
are running within its limits, metering and close attention to
impedances isn't all that important since the dawn of direct coupled
transistor amplifiers, which brought an end to the need to match the
output stage and transformer to the speaker impedances. Even the lower
limit of impedance stated by the maker will have a margin built in, so
in the case under consideration here, the amplifier will survive two
sets of 4 ohm speakers in parallel, subject to a possibility of
instability due to power supply overloading, and thermal problems if the
volume is turned up too high, so causing the output transistors to
exceed their safe dissipation levels.

Hence Scott and others will say of consumer gear "Use your ears, and of
it sounds good, that's okay." When they are setting up a session or
building a studio, repeatability is important, so they use meters and
cheat sheets to document the setup, so that the next session is the same
as the current one. For non critical applications, then "Use your ears"
is a good rule for pro gear and setups as well, as long as the original
specification was done correctly.


Use your ears with what, a Test CD with sweep frequency 20-20 kHz?

I may agree, man can detect distortion with 160 kbps MP3, but only with a single tone, but with complex music, no way can he hear what is actually distorted.

Now, are you talking thermal runaway with transistors and thermal noise, such as between metal film and carbon deposit resistors?

Jack



--
Tciao for Now!

John.


  #33   Report Post  
Posted to rec.audio.pro
Don Pearce[_3_] Don Pearce[_3_] is offline
external usenet poster
 
Posts: 2,417
Default Speaker Impedence ?

On Sat, 29 Apr 2017 10:16:56 -0700 (PDT), wrote:

Excuse me, but 3kHz is Midrange!!


Not when you're 67 it isn't

d

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

  #35   Report Post  
Posted to rec.audio.pro
Phil Allison[_4_] Phil Allison[_4_] is offline
external usenet poster
 
Posts: 499
Default Speaker Impedence ?

John Williamson wrote:


Even the lower
limit of impedance stated by the maker will have a margin built in, so
in the case under consideration here, the amplifier will survive two
sets of 4 ohm speakers in parallel, subject to a possibility of
instability due to power supply overloading, and thermal problems if the
volume is turned up too high, so causing the output transistors to
exceed their safe dissipation levels.


** Why the technobabble?

Output transistors have a temperature limit, beyond which self destruction of the chip is a certainty - followed by DC rail voltage appearing on the output.

Something to be carefully avoided.

IME few domestic amps have good heatsink overtemp or DC on the speaker line protection.


..... Phil


  #36   Report Post  
Posted to rec.audio.pro
[email protected] thekmanrocks@gmail.com is offline
external usenet poster
 
Posts: 1,742
Default Speaker Impedence ?

Phil Allison wrote: "
** Why the technobabble?

Output transistors have a temperature limit, beyond which self destruction of the chip is a certainty - followed by DC rail voltage appearing
on the output.

Something to be carefully avoided.

IME few domestic amps have good heatsink overtemp or DC on the speaker line protection.


..... Phil "


In plainer terms, ENGINEERS:

Obey the specs!
  #37   Report Post  
Posted to rec.audio.pro
[email protected] makolber@yahoo.com is offline
external usenet poster
 
Posts: 614
Default Speaker Impedence ?

The poor OP comes here to ask a simple question
and starts a bru hah ha.

Whats the matter with kids these days?
M

  #39   Report Post  
Posted to rec.audio.pro
Phil Allison[_4_] Phil Allison[_4_] is offline
external usenet poster
 
Posts: 499
Default Speaker Impedence ?

geoff wrote:


In plainer terms, ENGINEERS:

Obey the specs!


But what ARE the specs on such a vague spec.

Try this:

B&W 800 D3
Nominal Impedence 8 ohms (minimum 3.0 ohms)



** Can you post an impedance curve for the model ?

The maker says 8 ohms nominal and B&W are not likely to be liars.

Bet that 3 ohm minimum is way outisde the power band of music programme.

FYI:

The Quad ESL57 is quoted as nominal 16ohm, with a minimum of 1.7 ohms.

1.7ohms at 18kHz, only.



..... Phil









  #40   Report Post  
Posted to rec.audio.pro
geoff geoff is offline
external usenet poster
 
Posts: 1,812
Default Speaker Impedence ?

On 1/05/2017 9:45 PM, Phil Allison wrote:
geoff wrote:


In plainer terms, ENGINEERS:

Obey the specs!


But what ARE the specs on such a vague spec.

Try this:

B&W 800 D3
Nominal Impedence 8 ohms (minimum 3.0 ohms)



** Can you post an impedance curve for the model ?

The maker says 8 ohms nominal and B&W are not likely to be liars.

Bet that 3 ohm minimum is way outisde the power band of music programme.

FYI:

The Quad ESL57 is quoted as nominal 16ohm, with a minimum of 1.7 ohms.

1.7ohms at 18kHz, only.


I used to run 2 pairs, 2 in series each side, which made things a little
easier.

Now I have (stored away somewhere) a pair of ESL-63s, plus a scrap one
for parts, that are a pretty constant 8 ohms which comes across as
pretty much purely resistive.

Here's the best that google can find on B&W 800 Z (for an older lesser
version).

http://www.stereophile.com/content/b...lSCLXF6qtJv.97

geoff

Reply
Thread Tools
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
6 speaker wiring impedence question - how to calculate? [email protected] Tech 4 November 10th 07 01:16 AM
Speaker Impedence Tony F Car Audio 6 August 29th 06 09:37 PM
Mark Levinson Speaker Impedence Tony F Car Audio 1 January 2nd 06 08:45 AM
help with impedence Rodney St-Pierre Pro Audio 20 August 27th 04 04:47 PM
Help me with impedence Rodney St-Pierre Pro Audio 4 August 24th 04 11:16 PM


All times are GMT +1. The time now is 09:13 PM.

Powered by: vBulletin
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 AudioBanter.com.
The comments are property of their posters.
 

About Us

"It's about Audio and hi-fi"