Bromo wrote:
On 4/24/04 1:13 PM, in article cfxic.14174$0u6.2394685@attbi_s03, "Stewart
Pinkerton" wrote:


Given that the amplifiers' ability to drive difficult load is removed - then
the challenge is removed quite effectively.

Why? Where did you *ever* see a 'high end' maker claim that the
'superior' sound of his amp had anything to do with sheer power?

Power into low impedance and low to no global feedback is what I hear from
most amplifier advertisements.


OK, so there is another possible differentiator that would be tested for
validity: low/no global feedback vs normal global feedback.

Wouldn't it be nice if we can settle the issue of whether low/no global
feedback sounds any different?

Oh, that and a DC to daylight flatness with
low distortion.

You clearly have not read ads of certain tube amps.

Then you are agreeing with the poster to whom you are responding and to
Clark, both say exactly what you are saying. Those not agreeing with you
and Clark hold the view that "high end" amps have each an "sonic
signature" by which identifying one from another is normal. You have
spilled alot of ink, bandwith, to agree with those with whom you want to
have a difference of opinion. The amp company was no doubt of the latter
category,ie. their amps have a sound by which to identify it in a test
using Clark's rules, he left with his money.


AFAIK Clark brought the Challenge to a well known high-end amplifier company
and left with his money.

With those rules he is likely to keep it. Most amplifiers behavior into
comression makes or breaks them!

"So I tend to agree with another poster, the test is quite meaningless.
If you want to buy an amp, you should not have to correct its
frequency response due to its flaws. Better to buy an amp with no
flaws."

The ability to drive an extreme load at the edje of an amp's performance
is not at issue. When an amp is driven into such a load and is overlaoded
doesn't show a flaw, only that the load is outside it's performance design
specs. The real test is for those claiming "night and day" obvious anyone
can hear them differences between amps with similar performance specs. If
one looks enough some condition can be so extreme so as to drive one amp
into an unstable condition, that in this instance is irrelevant. It is a
purchase consideration when an amp of x cost and another of 10x are found
by test to sound no different. The same consideration would apply under
the extreme conditions you propose, why buy the second amp if the first
costs 1/10 the other and sounds the same under those conditions.

On 4/24/04 9:00 PM, in article H4Eic.16486$YP5.1208573@attbi_s02, "Nousaine"
wrote:

Bromo wrote:

On 4/24/04 1:10 PM, in article Acxic.14166$0u6.2392261@attbi_s03, "Nousaine"
wrote:

AFAIK Clark brought the Challenge to a well known high-end amplifier
company
and left with his money.

With those rules he is likely to keep it. Most amplifiers behavior into
comression makes or breaks them!

Am I to take your point as meaning that an amplifier operating in its linear
range will sound just like any other amplifier with similar frequency
response?

Not having measured or listened to but a dozen or so, I cannot say for sure,
but on the ones I measured, save tubes which distort in a very melodic way
throughout their range, I would agree.

I would further say this is a silly non-contest.

On 4/24/04 1:03 PM, in article P5xic.20708$aQ6.1263449@attbi_s51, "Nousaine"
wrote:

Given that the amplifiers' ability to drive difficult load is removed - then
the challenge is removed quite effectively.

Sure and how many "tough" loads are there? Stewart's speakers may qualify but
of the hunreds of home speakers I've tested I can't recall a single one
(including the 'stats) that would qualify as a difficult load to drive.

Martin Logan has a 1 Ohm impedance at the high end.
Apogees have a sub 1 Ohm impedance as well.
Thiels are notorious for requiring a lo of current in the bass (and tend to
be 3 Ohms)
Magnepans are -- magnepans and then to have a sub 5 Ohm load.

All of these are considered to be "difficult" to drive - and many integrated
amp manufactuers place warnings on their amps to not have speakes with
impedances that low! Many times in loud passages the amps could overheat
and trip thei protection circuit - or in extreme cases with no protections,
blow up!

But, if you don't see it - feel free to take the "40Wpc into 8 Ohms at 1Khz"
integrated and try to drive a Thiel 7.2....

It is true that many autosound enthusiasts like to wire multiple woofers,
often
with multiple coils, in ways that might qualify. But Richard Clark's challenge
has put the amp sound for autosound to rest as well.

He is trying to prove a negative, so the quest will be forever.

This whole thing struck a nerve - people doing a flashy sort of thing by
putting up a large sum of money with rules constructed so they won't ever be
"wrong"

The whole point of an amp is to source power - and matching that to the
needs of the speaker for good sound reproduction is the big task for that
link in the chain.

This "challenge" has so many if's and conditionals, that it generated more
heat and smoke than light.

It is understood by anyone that if you do not feed the speaker with enough
power, it won't sound good - too much power, and you will blow it out.
Conventional measurements should indicate if the speaker is likely to be
suitable, but to think we understand hearing and the processing our brains
go through to change pressure to sound to make it an end game is pure
arrogance to me!

On 4/24/04 10:15 AM, in article , "chung"
wrote:

Realisticqlly an amp running out of power is the main reason one would her
distortion vs. another amp. Given the power requirements across the
frequency band would reveal the differences in the amps -- the challenge is
a false challenge, then!

So you think any two amps with similar output power measurements would
sound the same? Works for me!

Nope - you would have to measure distortion, intermod, channel separation,
transient response, frequency response, and it is late I am sure I left
something out....

On the other hand, the high-enders' position is that there is something
magical about the sound of expensive amps that cannot be quantized via
measurements. That's what the challenge attempts to debunk.

I don't think it is a useful "challenge" - since you CANNOT divorce the
needs of a particular speaker or transducer from this and still come up with
anything useful to a consumer that I hope you are tring to "protect".

For instance Halcro advertises a THD that is much lower than most other
amplifiers at a power level not likely to ever be reached. Perhaps that is
their edge in this game of diminishing returns. The Theta Drednaught II
shows a great amount of frequency extension - and given that I have designed
(RF) amps for the last 10 years, I can see a small amount of value for that
if it is true. It means the source of distortion has been moved to the
component feeding the amp. Even if it is overkill, this is a HOBBY, where
the pursuit of perfection is part of the fun (the most fun being music).

So, in your opinion, why would anyone buy a $10K 100W amp, when there
are other 100W amps with low distortion available for $1K?

I have no opinion - it depends upon the amp and the speaker. I have some
Thield 2.4's and it required a fair amount of current to make the bass sound
good. This made me seek out the best value to correct it given that I only
had about 70-80Wpc. I ended up with a NAD S200 - which made the bass sound
good without muddying the upper frequencies. I ended up paying more than
$1k for it. (It was 225Wpc).

If someone offers me a hand crafted piece of electronics, with a vanishingly
low noise floor, low IMD and harmonics, incrementally better than your $1k
amp, and wants to charge me $2-4k for it (more realistic) - I wouldn't fault
him or her at all. Why should I?

(Thomas A) wrote:


(Nousaine) wrote in message
news:Acxic.14166$0u6.2392261@attbi_s03...
wrote:

Bromo wrote in message

....large snips......


This sounds like a bogus 'challenge' to me.

There are more things, e,g, it cost 100-300 dollars and you need to be
a subscriber of a car magazine or worker in car industry, as I
understand it. The amp according to these rules must be a car amp.
However, if I would do the challenge, I would seek up two amps with
different HP filtering in the bass range (if such exist among car
amps; there is nothing in the rules what I can see about the built in
normal HP filtering of amps to avoid DC). Play the music to the film
"Fifth Element" and use speakers with e.g. 10 x 15 inch woofers in a
closed box system in a sealed small room. Play the song where there is
a sweep going down to 5 Hz at loud volumes and try to "feel" the
difference in the body. 1.5-3 dB difference in the 7-15 Hz region may
be percieved differently. Challenge rules, see


http://groups.google.com/groups?q=%2...enge+rules+gro
up:rec.audio.car&hl=en&lr=&ie=UTF-8&oe=ISO-8859-1&group=rec.audio.car&selm
=3ff8669c.126950265%40news.east.cox.net&rnum=6

AFAIK Clark brought the Challenge to a well known high-end amplifier
company
and left with his money.

Just a note, I would say that at least 50% of the amps fails to be
completely transparent in tests made by the Swedish Acoustical
Society. The use before/after listning tests, blind, with bass-heavy
music (down to 5 Hz signals). These flaws would probably never be
detected in "normal" speaker systems, e.g. B/W 801.

T

Oh I get it. You have to have a DIY subwoofer like mine before amps ain't amps.
There aren't currently any consumer passive (or even active) subwoofers that
have response below 15 Hz.

And here, Mr Wheeler says that a 10 Hz subwoofer is "useless." Maybe that's why
the high-end can't prove that amps ain't amps ..... none of them have a
subwoofer with adequate bandwidth. Indeed most of them don't have subwoofers
at all. They're too "slow" and the bass stays in the room so you get to
hear/feel it. The fast-bass sneaks out too quickly.

On 4/24/04 2:31 PM, in article ,
" wrote:

I agree about current limits being the real physical reasons an amp
might sound different from another. But those advocating the inherent
amp sound different view say that when with equal current capacity,
amps will still sound different.

Yes - this makes this sort f test rather useless in information or
enlightenment.

If I buy sme Maggie 3.6R's I has better get an amp with more cajones than
the Yamaha integrated, for instance.

If I get a Lowther horn speaker - I would do with a lot less power.

I do not see how this "challenge" serves anyone but the ego of the
"debunker"...

On 4/24/04 9:00 PM, in article y4Eic.16484$YP5.1208556@attbi_s02,
" wrote:

I think you have failed to grasp what the test is to exclude in amps.

Exclude *what* in amps?

For purposes of discussion let us say two amps from different companies
are to be tested. One costs 1000 k and has performance and specs very
similar to another at 10000k. The latter has been reviewed wherein it was
said it had night and day differences in a list of sound qualties to which
a list of common audio writing labels is attached. They said specifically
the obvious difference was with comparsion to the first amp. Now we do
the test and no one can pick the amps from another above the level of
guessing alone. The test was to see if the percieved list of quality
labels attached to the second but said to be missing in the first was an
artifact of the perception process or inherent in the amps. The results
suggest it was not in the amps. Because the performance specs were
similar, the load into which they were driven was not a variable, only the
claimed "night and day" differences. Both would agree that amp limiting
was not in the picture.

The contest is a silly endevour because of the various loads an amplifier is
asked to drive into - each speaker is different in impedance and the amount
of current required in order to get a nice, flat response out of it (or a
response the listener finds to his or her liking).

On 4/24/04 9:00 PM, in article %4Eic.16489$YP5.1208529@attbi_s02, "Nousaine"
wrote:

Suppose not if this is the sort of challenge that is put forth - remove any
possible way of differentiating one amp from another then claim victory when
you can't tell the difference!

This tells me you really don't understand the high-end. All the factors that
Clark includes in his prereqs are well known and well understood issues that
when viewed as problems have been solved long ago.

Fine - I must not "understand" - so enlighten me!

The subjectivist crowd and the high-end, on the other hand, claim that there
are "other" factors which cannot be measured with traditional tools that
contribute to the sound of amplifiers. Clark's prereqs could not possibly rule
out those factors as they are all standard things.

I would concede that we do not have a full 100% understanding of all
possible sonic differences. I do not need to offer $10k in a debunking
escapade to realize that the world is not going to be black and white
despite my earnest desire to try to force it there.

I am an RF engineer by profession and training - and I have to figure out
new ways to measure things all the time. Why should audio be different?

Sure, there might be people that fool themselves into thinking that there is
some ineffable difference between a Yamaha and a Halcro - and given the way
this test is set up - it is skewed to prefer the Yamaha since the amplifiers
aren't going to be driven into compression where any differences might be
seen.

If your conception of the "high end" is going on a debunking fest - I don't
get it - and probably never will.

S888Wheel wrote:

From: chung
Date: 4/24/2004 7:15 AM Pacific Standard Time
Message-id:



On the other hand, the high-enders' position is that there is something
magical about the sound of expensive amps that cannot be quantized via
measurements. That's what the challenge attempts to debunk.


Why do objectivists continue to burn this straw man? I don't know any
subjectivists who claim any "magic" is at work.


Oh yeah? A casual search finds the following post:

http://groups.google.com/groups?q=tu...y.edu&rnu m=3

Here's what Zipser said in that post:

"Probably the one and only solid state amplifier line that sonically
posseses the same magic as your tube amplifier is the PASS Labs Aleph
series of amplifiers."

There are many references to "tube magic"; just do a google search on
the various audio newsgroups.

BTW, you misunderstood what I said. I said that some high-enders believe
there is something magical about the sound of certain highly touted
amps. That does not mean that I am saying that subjectivists believe
there is magic at work. It simply means that said high-enders cannot
explain why these amps sound so great, since measurements do not explain
such greatness.

It seems like you are imagining a strawman being burned. When someone
says that something sounds magical, do you always assume that someone is
saying there is magic at work?

Bromo wrote:
On 4/24/04 2:31 PM, in article ,
" wrote:

I agree about current limits being the real physical reasons an amp
might sound different from another. But those advocating the inherent
amp sound different view say that when with equal current capacity,
amps will still sound different.

Yes - this makes this sort f test rather useless in information or
enlightenment.


As compared to, say, a typical high-end review of an amp?

I do not see how this "challenge" serves anyone but the ego of the
"debunker"...

Then, as many have already pointed out here, you don't understand
why the challenge was laid down in the first place. It is a response
to typical audiophile claims.


--

-S.

"They've got God on their side. All we've got is science and reason."
-- Dawn Hulsey, Talent Director

Bromo wrote:
On 4/24/04 10:15 AM, in article , "chung"
wrote:

Realisticqlly an amp running out of power is the main reason one would her
distortion vs. another amp. Given the power requirements across the
frequency band would reveal the differences in the amps -- the challenge is
a false challenge, then!

So you think any two amps with similar output power measurements would
sound the same? Works for me!

Nope - you would have to measure distortion, intermod, channel separation,
transient response, frequency response, and it is late I am sure I left
something out....

So you just stated that there are differences that are in addition to
the drive capabilities of the amps. So just insuring that two amps have
similar drive capabilities does not insure that they sound the same.
Therefore you just prove that the challenge is not faulty at all!


On the other hand, the high-enders' position is that there is something
magical about the sound of expensive amps that cannot be quantized via
measurements. That's what the challenge attempts to debunk.

I don't think it is a useful "challenge" - since you CANNOT divorce the
needs of a particular speaker or transducer from this and still come up with
anything useful to a consumer that I hope you are tring to "protect".

Note that they are not saying that they will match the noise,
distortion, interchannel effects, transient responses, etc. So if those
things would differentiate amps, then the challenge is meaningful.


For instance Halcro advertises a THD that is much lower than most other
amplifiers at a power level not likely to ever be reached. Perhaps that is
their edge in this game of diminishing returns. The Theta Drednaught II
shows a great amount of frequency extension - and given that I have designed
(RF) amps for the last 10 years, I can see a small amount of value for that
if it is true. It means the source of distortion has been moved to the
component feeding the amp. Even if it is overkill, this is a HOBBY, where
the pursuit of perfection is part of the fun (the most fun being music).

Question then is whether the Halcro can be differentiated from any other
amp with the same drive capabilities and similar frequency response. The
challenge can answer that.


So, in your opinion, why would anyone buy a $10K 100W amp, when there
are other 100W amps with low distortion available for $1K?

I have no opinion - it depends upon the amp and the speaker. I have some
Thield 2.4's and it required a fair amount of current to make the bass sound
good. This made me seek out the best value to correct it given that I only
had about 70-80Wpc. I ended up with a NAD S200 - which made the bass sound
good without muddying the upper frequencies. I ended up paying more than
$1k for it. (It was 225Wpc).

If someone offers me a hand crafted piece of electronics, with a vanishingly
low noise floor, low IMD and harmonics, incrementally better than your $1k
amp, and wants to charge me $2-4k for it (more realistic) - I wouldn't fault
him or her at all. Why should I?

But don't you want to know if another amp with the same output drive as
your NAD will sound the same? Maybe you don't, but the question is a
meaningful one, and I fail to see why you think you know the answer
before the test.

wrote in message ...
"So I tend to agree with another poster, the test is quite meaningless.
If you want to buy an amp, you should not have to correct its
frequency response due to its flaws. Better to buy an amp with no
flaws."

The ability to drive an extreme load at the edje of an amp's performance
is not at issue. When an amp is driven into such a load and is overlaoded
doesn't show a flaw, only that the load is outside it's performance design
specs. The real test is for those claiming "night and day" obvious anyone
can hear them differences between amps with similar performance specs. If
one looks enough some condition can be so extreme so as to drive one amp
into an unstable condition, that in this instance is irrelevant. It is a
purchase consideration when an amp of x cost and another of 10x are found
by test to sound no different. The same consideration would apply under
the extreme conditions you propose, why buy the second amp if the first
costs 1/10 the other and sounds the same under those conditions.

Fully agreed. There is no meaning to pay more if it is only "sound
quality" that is seeked. There may be other things, features, looks,
build quality.

However, the test is still meaningless in one sense. If I look at two
different speaker with very similar dispersion pattern and distorsion
spec, but with completely different frequency response, both speaker
would sound the same after correction with an EQ. Quite meaningless if
the test purpose is to reveal whether there are audible differences
between speakers. The need to EQ shows that there must be some flaws
that has to be corrected, right?

T

On 4/25/04 1:25 AM, in article ZYHic.26492$IW1.1268676@attbi_s52, "Nousaine"
wrote:

Oh I get it. You have to have a DIY subwoofer like mine before amps ain't
amps.
There aren't currently any consumer passive (or even active) subwoofers that
have response below 15 Hz.

So the sub 20Hz distortion might not be an appropriate measure.

The largest logical problem with "debunking" is that you are placing
yourself in the position of proving a negative (that a SS amp does NOT have
any differences) - and since all you can do is discredit (which is the idiot
half brother of proper scientific light), we see all kinds of limited tests
with "rewards" and "challenges" - but it beings us back to the problem of
proving negatives.

The time and effort might be spent a bit more productively - perhaps trying
to research and measure all sources of sonic imperfections not already known
- pushing the forefront of hearing sciences, and so on.

From: (Nousaine)
Date: 4/24/2004 10:25 PM Pacific Standard Time
Message-id: ZYHic.26492$IW1.1268676@attbi_s52

(Thomas A) wrote:


(Nousaine) wrote in message
news:Acxic.14166$0u6.2392261@attbi_s03...
wrote:

Bromo wrote in message

....large snips......


This sounds like a bogus 'challenge' to me.

There are more things, e,g, it cost 100-300 dollars and you need to be
a subscriber of a car magazine or worker in car industry, as I
understand it. The amp according to these rules must be a car amp.
However, if I would do the challenge, I would seek up two amps with
different HP filtering in the bass range (if such exist among car
amps; there is nothing in the rules what I can see about the built in
normal HP filtering of amps to avoid DC). Play the music to the film
"Fifth Element" and use speakers with e.g. 10 x 15 inch woofers in a
closed box system in a sealed small room. Play the song where there is
a sweep going down to 5 Hz at loud volumes and try to "feel" the
difference in the body. 1.5-3 dB difference in the 7-15 Hz region may
be percieved differently. Challenge rules, see


http://groups.google.com/groups?q=%2...enge+rules+gro
up:rec.audio.car&hl=en&lr=&ie=UTF-8&oe=ISO-8859-1&group=rec.audio.car&selm
=3ff8669c.126950265%40news.east.cox.net&rnum=6

AFAIK Clark brought the Challenge to a well known high-end amplifier
company
and left with his money.

Just a note, I would say that at least 50% of the amps fails to be
completely transparent in tests made by the Swedish Acoustical
Society. The use before/after listning tests, blind, with bass-heavy
music (down to 5 Hz signals). These flaws would probably never be
detected in "normal" speaker systems, e.g. B/W 801.

T

Oh I get it. You have to have a DIY subwoofer like mine before amps ain't
amps.
There aren't currently any consumer passive (or even active) subwoofers that
have response below 15 Hz.

And here, Mr Wheeler says that a 10 Hz subwoofer is "useless." Maybe that's
why
the high-end can't prove that amps ain't amps ..... none of them have a
subwoofer with adequate bandwidth. Indeed most of them don't have subwoofers
at all. They're too "slow" and the bass stays in the room so you get to
hear/feel it. The fast-bass sneaks out too quickly.








Please try to get your facts straight. I said a 6hz tone is useless in highend.
I still say it's useless for me. I guess Tom finds some use for it. There are
plenty of speakers with adequate bandwidth for the purpose of playing music.
Many of us are not interested in reproducing train wrecks and damaging the
structures of our homes.

On 4/25/04 10:14 AM, in article , "chung"
wrote:

So you think any two amps with similar output power measurements would
sound the same? Works for me!

Nope - you would have to measure distortion, intermod, channel separation,
transient response, frequency response, and it is late I am sure I left
something out....

So you just stated that there are differences that are in addition to
the drive capabilities of the amps. So just insuring that two amps have
similar drive capabilities does not insure that they sound the same.
Therefore you just prove that the challenge is not faulty at all!

The challenge is faulty for the following reasons:

1. You are stuck with that guys' speakers - bad sounding speakers will mask
an amps sound.
2. The person will equalize his amplifier - since his amplifier has sound
qualities he has to equalize to sound flat.

On 4/25/04 12:03 PM, in article , "S888Wheel"
wrote:

Please try to get your facts straight. I said a 6hz tone is useless in
highend.
I still say it's useless for me. I guess Tom finds some use for it. There are
plenty of speakers with adequate bandwidth for the purpose of playing music.
Many of us are not interested in reproducing train wrecks and damaging the
structures of our homes.

Speaking of this - in signal envelope and transients - would the 6Hz
performance be important in an amplifier? I mean, a sharp rising tone might
have a 6Hz component - would it be reflected in this or is there something
else in the amp that would help with signal envelope and transient behavior?

From: chung
Date: 4/24/2004 10:28 PM Pacific Standard Time
Message-id: M%Hic.17630$YP5.1284125@attbi_s02

S888Wheel wrote:

From: chung
Date: 4/24/2004 7:15 AM Pacific Standard Time
Message-id:



On the other hand, the high-enders' position is that there is something
magical about the sound of expensive amps that cannot be quantized via
measurements. That's what the challenge attempts to debunk.


Why do objectivists continue to burn this straw man? I don't know any
subjectivists who claim any "magic" is at work.


Oh yeah? A casual search finds the following post:


http://groups.google.com/groups?q=tu...o.high-end&hl=
en&lr=&ie=UTF-8&oe=UTF-8&group=rec.audio.high-end&selm=7mu81k%246gr%241%40
agate.berkeley.edu&rnum=3

Here's what Zipser said in that post:

"Probably the one and only solid state amplifier line that sonically
posseses the same magic as your tube amplifier is the PASS Labs Aleph
series of amplifiers."

There are many references to "tube magic"; just do a google search on
the various audio newsgroups.


Obviously figurative speech refering to a prefered sound from tubes. Hardly a
claim of the paranormal.

BTW, you misunderstood what I said. I said that some high-enders believe
there is something magical about the sound of certain highly touted
amps.

Well please clarify what you are saying. Are you complaining about figurative
speech or are you complaining about claims of paranormal activity?

That does not mean that I am saying that subjectivists believe
there is magic at work.

It did seem like you were.

It simply means that said high-enders cannot
explain why these amps sound so great, since measurements do not explain
such greatness.

So? Many people cannot explain many things they enjoy in life. That fact per se
does not mean they are making claims of paranormal experiences.


It seems like you are imagining a strawman being burned. When someone
says that something sounds magical, do you always assume that someone is
saying there is magic at work?








It is not like such straw men have never been burned in the past by
objectvists. If you are complaining about hyperbole fine. It didn't look that
way to me. It looked like you were trying to tar and feather subjectivists as
believers in the paranormal. While I am sure many are, I am even more sure that
some are not. And the same is true for objectivists.

On 4/25/04 10:13 AM, in article , "Steven
Sullivan" wrote:

Bromo wrote:
On 4/24/04 2:31 PM, in article ,
" wrote:

I agree about current limits being the real physical reasons an amp
might sound different from another. But those advocating the inherent
amp sound different view say that when with equal current capacity,
amps will still sound different.

Yes - this makes this sort f test rather useless in information or
enlightenment.

As compared to, say, a typical high-end review of an amp?

The point here is how this "challenge"/test is supposed to enlighten - to
point out that it might be uninformative and might steer people into wasting
money as a poorly written and analyzed review might be - isn't the
"challenge" supposed to be better than that and serve the general
enlightenment of people in general? If it is no better than the 'high end
reviews' you are disparaging, it is adding to the much in high end rather
than trying to sort things out.

It really bothers me that the results of this might cause people to
inappropriately pair inefficient speakers with amps incapable of driving
them.

(BTW, I happen to like the subjectivist reviews, myself, as I have noticed
differences in a entire system with different amplification - which I am
convinced have as much to do with the speaker-amp interaction as anything
else.)

I do not see how this "challenge" serves anyone but the ego of the
"debunker"...

Then, as many have already pointed out here, you don't understand
why the challenge was laid down in the first place. It is a response
to typical audiophile claims.

I do know why it was laid down - I am questioning its value in discrediting
the marketing departments of high end audio firms' employ, since it risks,
through its own hype, of throwing out some other more important truths, too.

Stewart Pinkerton wrote:
On 24 Apr 2004 15:24:40 GMT, (Thomas A)
wrote:

However, if I would do the challenge, I would seek up two amps with
different HP filtering in the bass range (if such exist among car
amps; there is nothing in the rules what I can see about the built in
normal HP filtering of amps to avoid DC). Play the music to the film
"Fifth Element" and use speakers with e.g. 10 x 15 inch woofers in a
closed box system in a sealed small room. Play the song where there is
a sweep going down to 5 Hz at loud volumes and try to "feel" the
difference in the body. 1.5-3 dB difference in the 7-15 Hz region may
be percieved differently. Challenge rules, see

http://groups.google.com/groups?q=%2...cox.net&rnum=6

Unfortunately, you failed to notice that in test condition no. 5,
Richard is allowed to EQ the amps to have the same frequency response,
negating this kind of cheap shot.

FWIW I found Clark's challenge and some of his replies to criticisms,
here

http://www.talkaudio.co.uk/vbb/showt...threadid=18815

And alas it doesn't seem unusual for critics to have not actually
read the terms of the challenge (though that doesnt' stop them from
making erroneous claims about it!)

http://www.soundandvisionmag.com/idealbb/view.asp?topicID=31069&forumID=29&catID=1&search=1 &searchstring=&sessionID={14295840-707C-4B98-9F45-636A9838AAAE}

--

-S.

"They've got God on their side. All we've got is science and reason."
-- Dawn Hulsey, Talent Director

Bromo wrote:
On 4/24/04 9:00 PM, in article %4Eic.16489$YP5.1208529@attbi_s02, "Nousaine"

Sure, there might be people that fool themselves into thinking that there is
some ineffable difference between a Yamaha and a Halcro -

Alas, not *might*. It's taken as a *given* by audiophile culture.

If you're unaware of such prejudices existing in audiophilia, then
you can't understand the background that produced Clark's challenge.

--

-S.

"They've got God on their side. All we've got is science and reason."
-- Dawn Hulsey, Talent Director

On 24 Apr 2004 18:35:33 GMT, Bromo wrote:

On 4/24/04 1:13 PM, in article cfxic.14174$0u6.2394685@attbi_s03, "Stewart
Pinkerton" wrote:


Given that the amplifiers' ability to drive difficult load is removed - then
the challenge is removed quite effectively.

Why? Where did you *ever* see a 'high end' maker claim that the
'superior' sound of his amp had anything to do with sheer power?

Power into low impedance and low to no global feedback is what I hear from
most amplifier advertisements. Oh, that and a DC to daylight flatness with
low distortion.

You will *never* see 'DC to blue light' and no global feedback
mentioned in connection with the same amplifier. You'll also not see
ability into low loads mentioned for anything but Krell and H-K. You
*will* see technobable like 'microdynamics' and 'soundstaging' bandied
about by ragazine reviewers - who will *never* submit to DBTs.

My Krell will drive a 1-ohm load continuously, but that has nothing to
do with how it *sounds* on normal speakers.

The point is that how it can source a 1 ohm current load means you aren't
restricted to 'normal' speakers (whatever those are) - and if there is a ton
of current required - you have it without the amplifier going into some sort
of foldback.

Which has what exactly to do with any notion of 'superior sound' into
normal speakers? You seem to have completely missed the claimed point
of 'high end' amplifiers. Please note that I agree with your point of
view, it's just that you seem to have stepped into a debate with no
actual conception of one side of it.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Sat, 24 Apr 2004 23:47:07 GMT, (S888Wheel) wrote:

From: chung
Date: 4/24/2004 7:15 AM Pacific Standard Time
Message-id:

On the other hand, the high-enders' position is that there is something
magical about the sound of expensive amps that cannot be quantized via
measurements. That's what the challenge attempts to debunk.

Why do objectivists continue to burn this straw man? I don't know any
subjectivists who claim any "magic" is at work.

But you *do* know lots of subjectivists who claim that a 'high end'
amp has obvious and easily audible differences from a 'mid-fi' amp, do
you not?

No matter what technobabble term is claimed as the mechanism, it's
basically all just 'magic' which is claimed to cause the difference in
sound - which does not of course exist in the physical world.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On 4/24/04 11:22 PM, in article , "chung"
wrote:

Bromo wrote:
On 4/24/04 1:13 PM, in article cfxic.14174$0u6.2394685@attbi_s03, "Stewart
Pinkerton" wrote:


Given that the amplifiers' ability to drive difficult load is removed -
then
the challenge is removed quite effectively.

Why? Where did you *ever* see a 'high end' maker claim that the
'superior' sound of his amp had anything to do with sheer power?

Power into low impedance and low to no global feedback is what I hear from
most amplifier advertisements.


OK, so there is another possible differentiator that would be tested for
validity: low/no global feedback vs normal global feedback.

Wouldn't it be nice if we can settle the issue of whether low/no global
feedback sounds any different?

It won't be settled - you cannot prove a negative.

On 4/24/04 11:25 PM, in article ,
" wrote:

"So I tend to agree with another poster, the test is quite meaningless.
If you want to buy an amp, you should not have to correct its
frequency response due to its flaws. Better to buy an amp with no
flaws."

The ability to drive an extreme load at the edje of an amp's performance
is not at issue. When an amp is driven into such a load and is overlaoded
doesn't show a flaw, only that the load is outside it's performance design
specs.

Actually testing to the extremes generally *are* int he design specs. Also,
the specifications are generally vague in many ways - aside from that a
lower impedance in the AB amplifier can generate greater distortion than at
a higher impedance.

An amp unable to properly drive a speaker is a VERY important measure of an
amp - especially if the amp and speaker are YOUR amps and speakers. If both
amps claim they can have enough current to power a Maggie 20.1 but one seems
to compress better on high peaks - well, which one is the "better" amp in
this case?

I recall reading a review in Absolute Sound where they compared a bunch of
amps ranging from $2k (Rotel) to about $6K - and their only comment was that
at normal listening levels, any of the amps would be easy to live with - and
the only differences were heard at a high level of drive.

The real test is for those claiming "night and day" obvious anyone
can hear them differences between amps with similar performance specs.

In the AS, they didn't make that claim in that one review if it makes you
feel any better.

The more I read and post in this thread, it seems to me that most of the
effort is trying to discredit a marketing department - and a few reviewers.

What benefit would I, as a consumer, would get from this effort? Especially
since it is designed not to help me find an amp that would match my speaker
well?

If
one looks enough some condition can be so extreme so as to drive one amp
into an unstable condition, that in this instance is irrelevant.

This is ABSOLUTELY an important issue - unconditional stability is important
to understand before you plunk down any amount of money be it $10 or $10,000
for the amplifier.

In fact, this would be MORE IMPORTANT to point out about various amplifiers
than creating some sort of limited test to try to prove a negative.

It is a
purchase consideration when an amp of x cost and another of 10x are found
by test to sound no different. The same consideration would apply under
the extreme conditions you propose, why buy the second amp if the first
costs 1/10 the other and sounds the same under those conditions.

But how relevant are those conditions to the people this demonstration is
trying to educate?

A really thorough ring out of both amplifiers with measurements followed by
a series of sound tests (blind tests) with speakers of various loads and
timbers plus stress testing to prove stability, protection and so on, would
be much more useful as far as education.

On Sun, 25 Apr 2004 05:13:36 GMT, Bromo wrote:

On 4/24/04 10:15 AM, in article , "chung"
wrote:

So, in your opinion, why would anyone buy a $10K 100W amp, when there
are other 100W amps with low distortion available for $1K?

I have no opinion - it depends upon the amp and the speaker. I have some
Thield 2.4's and it required a fair amount of current to make the bass sound
good. This made me seek out the best value to correct it given that I only
had about 70-80Wpc. I ended up with a NAD S200 - which made the bass sound
good without muddying the upper frequencies. I ended up paying more than
$1k for it. (It was 225Wpc).

If someone offers me a hand crafted piece of electronics, with a vanishingly
low noise floor, low IMD and harmonics, incrementally better than your $1k
amp, and wants to charge me $2-4k for it (more realistic) - I wouldn't fault
him or her at all. Why should I?

That's not the point. There are many so-called 'high end'
manufacturers charging $10-20k for amplifiers which are *less* capable
than your S200 (virtually all the tube ones, for a start). Further,
what's the point of vanishingly low noise and artifacts, when such a
device doesn't *sound* any different from your NAD?

Forget 'high end' amps, they are mere conceits - spend the money on
better speakers - such as CS7.2s!
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Sun, 25 Apr 2004 05:10:54 GMT, Bromo wrote:

On 4/24/04 1:03 PM, in article P5xic.20708$aQ6.1263449@attbi_s51, "Nousaine"
wrote:

Given that the amplifiers' ability to drive difficult load is removed - then
the challenge is removed quite effectively.

Sure and how many "tough" loads are there? Stewart's speakers may qualify but
of the hunreds of home speakers I've tested I can't recall a single one
(including the 'stats) that would qualify as a difficult load to drive.

Martin Logan has a 1 Ohm impedance at the high end.

Where there is virtually no power to be delivered to the speakers.
I've not found M-Ls to be particularly amplifier fussy.

Apogees have a sub 1 Ohm impedance as well.

Only one model - the old Scintilla. All others have a mostly resistive
3-4 ohms impedance, but they do like lots of power as they're not very
sensitive.

Thiels are notorious for requiring a lo of current in the bass (and tend to
be 3 Ohms)

Indeed yes, but they're quite sensitive in the main, so a good
60-watter will generally do - and that's about the easiest size of amp
to design.

Magnepans are -- magnepans and then to have a sub 5 Ohm load.

Any half-decent amp should drive a 4-5 ohm load without problems, it
then just becomes a matter of how loud you want to play.

All of these are considered to be "difficult" to drive - and many integrated
amp manufactuers place warnings on their amps to not have speakes with
impedances that low!

I have not seen *any* respectable integrated amp (I'm not talking
about cheap receivers or surround-sound amps) which warns against 4
ohm loads. The decent ones such as Arcam are perfectly capable of
driving 2-ohm loads.

Many times in loud passages the amps could overheat
and trip thei protection circuit - or in extreme cases with no protections,
blow up!

You must have different experience to mine regarding what any
reasonable person would call 'hi-fi' equipment.

But, if you don't see it - feel free to take the "40Wpc into 8 Ohms at 1Khz"
integrated and try to drive a Thiel 7.2....

No reasonable person would try such a thing. What is your point?

It is true that many autosound enthusiasts like to wire multiple woofers, often
with multiple coils, in ways that might qualify. But Richard Clark's challenge
has put the amp sound for autosound to rest as well.

He is trying to prove a negative, so the quest will be forever.

This whole thing struck a nerve - people doing a flashy sort of thing by
putting up a large sum of money with rules constructed so they won't ever be
"wrong"

Tell that to the 'high enders' who claim that say a Pass Labs Aleph
1.2 at £12,000 will sound 'obviously, night and day' different from a
$500 Yamaha AX-592. They have similar power capability, but claims
made for 'sound quality' are very different!
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Bromo wrote:
On 4/25/04 10:14 AM, in article , "chung"
wrote:

So you think any two amps with similar output power measurements would
sound the same? Works for me!

Nope - you would have to measure distortion, intermod, channel separation,
transient response, frequency response, and it is late I am sure I left
something out....

So you just stated that there are differences that are in addition to
the drive capabilities of the amps. So just insuring that two amps have
similar drive capabilities does not insure that they sound the same.
Therefore you just prove that the challenge is not faulty at all!

The challenge is faulty for the following reasons:

1. You are stuck with that guys' speakers - bad sounding speakers will mask
an amps sound.

So you are now saying that the test is not faulty if you can use your
own speakers? For your own buying decision, that is a reasonable
stipulation. And maybe that guy would even agree to use your own
speakers if you bring them along. But how do you know "bad sounding
speakers" are being used in the test?

For the general question of what makes amps sound different, I don't see
any problem with using a pair of speakers that have reasonable
performance. As long as the identity of the speakers is revealed, that
is still a valid test. I don't see any ads of expensive amps that have a
condition that only certain speakers have to be used for it to sound great.


2. The person will equalize his amplifier - since his amplifier has sound
qualities he has to equalize to sound flat.

Like you said in a previous post, the majority of solid state amps have
flat frequency response. So I don't see why that is a big concern. If
you leave out that condition, then the test is truly meaningless, since
you can simply put a resistor in series with the output and achieve a
very different sound, since you have messed up the frequency response.

In any event, isn't it nice to know that if two amps have similar
frequency responses, then they sound the same? That's why the challenge
is interesting, and potentially very useful to consumers.

S888Wheel wrote:


BTW, you misunderstood what I said. I said that some high-enders believe
there is something magical about the sound of certain highly touted
amps.

Well please clarify what you are saying. Are you complaining about figurative
speech or are you complaining about claims of paranormal activity?



It really speaks volumes about how you are preconditioned to read
certain posts from the non-subjectivist side. I was not complaining
about anything at all, and yet you took it that I was.

OK, so there is another possible differentiator that would be
tested for
validity: low/no global feedback vs normal global feedback.

Wouldn't it be nice if we can settle the issue of whether low/no
global
feedback sounds any different?

It won't be settled - you cannot prove a negative.

"It's true that absence of evidence is not evidence of absence, but it
would be churlish to ignore the data."

Norm Strong

On 4/25/04 1:38 PM, in article 7ISic.32063$w96.2204064@attbi_s54, "Stewart
Pinkerton" wrote:

But, if you don't see it - feel free to take the "40Wpc into 8 Ohms at 1Khz"
integrated and try to drive a Thiel 7.2....

No reasonable person would try such a thing. What is your point?

The point I was making is that the "challenge" when hyped (a $10k "prize is
hype in this case) might make an average consumer think that any old amp
low, mid or hi-fi was capable of driving any old speaker because "they sound
the same."

I have an AVR200 that used to drive my Thiel 2.4's - I now use a NADS200 to
do the same - the articulation and bass response improved noticably due to
the power - and according to the data sheet I had up to 90W available to do
that (1kHz at 4Ohms was supposed to be 140W). The extra current really
helped the sound I figure when driving that speaker. Made a difference,
when I expected very little.

On 4/25/04 1:34 PM, in article AESic.32031$w96.2201891@attbi_s54, "Steven
Sullivan" wrote:

Bromo wrote:
On 4/24/04 9:00 PM, in article %4Eic.16489$YP5.1208529@attbi_s02, "Nousaine"

Sure, there might be people that fool themselves into thinking that there is
some ineffable difference between a Yamaha and a Halcro -

Alas, not *might*. It's taken as a *given* by audiophile culture.

If you're unaware of such prejudices existing in audiophilia, then
you can't understand the background that produced Clark's challenge.

I do know of all the marketing BS that goes on in this hobby. I am looking
at a Halcro Ad on this month's Stereophile (pg. 15, May '04) right now.
They have a bunch of gushing - nothing too much other than typical hype.
Their claims are easily verifiable - a low IMD, so low you can't measure it.
The most accurate and quietest phono stage available. You could compare
their response to the ideal RIAA curve and measure the IMD at full power.

If you measure any deviation in the RIAA curve, or any IMD's - you have
caught them in a lie and you can feel confident in debunking them.

I only say this because it would be easy to disprove this or verify it -
rather than have a rather complicated and limited "challenge" to prove a
negative.

I also think that Sensible Sound tends to have a good "Skeptimania" columns
as well, showing the BS laden traps some can find themselves in.

Now, where did I put those battery "enhanced" Audioquest cables ..... :-)

Bromo wrote:

It won't be settled - you cannot prove a negative.

In an absolute sense, of course. But, in a probabilistic perspective,
one can sensibly conclude that something is very unlikely.

chung wrong:

S888Wheel wrote:

From: chung
Date: 4/24/2004 7:15 AM Pacific Standard Time
Message-id:



On the other hand, the high-enders' position is that there is something
magical about the sound of expensive amps that cannot be quantized via
measurements. That's what the challenge attempts to debunk.


Why do objectivists continue to burn this straw man? I don't know any
subjectivists who claim any "magic" is at work.


Oh yeah? A casual search finds the following post:


http://groups.google.com/groups?q=tu...o.high-end&hl=
en&lr=&ie=UTF-8&oe=UTF-8&group=rec.audio.high-end&selm=7mu81k%246gr%241%40
agate.berkeley.edu&rnum=3

Here's what Zipser said in that post:

"Probably the one and only solid state amplifier line that sonically
posseses the same magic as your tube amplifier is the PASS Labs Aleph
series of amplifiers."

There are many references to "tube magic"; just do a google search on
the various audio newsgroups.

Holy cow. This means that Steve Maki's Yamaha Integrated amplifier must have
'tube magic' too .....Steve Zipser proved it sounded exactly like his Pass
Aleph monoblocks driving those huge Dunlavy towers.

That darned Yamaha sounds exactly like my Parasound integrated amps and my
Brystons and the 5000 Watt Crown. So they must also have "tube magic."


Oh! The shame of it all.


BTW, you misunderstood what I said. I said that some high-enders believe
there is something magical about the sound of certain highly touted
amps. That does not mean that I am saying that subjectivists believe
there is magic at work. It simply means that said high-enders cannot
explain why these amps sound so great, since measurements do not explain
such greatness.

It seems like you are imagining a strawman being burned. When someone
says that something sounds magical, do you always assume that someone is
saying there is magic at work?

I have always loved the smell of smoke.

Bromo wrote:

On 4/24/04 11:22 PM, in article , "chung"
wrote:

Bromo wrote:
On 4/24/04 1:13 PM, in article cfxic.14174$0u6.2394685@attbi_s03, "Stewart
Pinkerton" wrote:


Given that the amplifiers' ability to drive difficult load is removed -
then
the challenge is removed quite effectively.

Why? Where did you *ever* see a 'high end' maker claim that the
'superior' sound of his amp had anything to do with sheer power?

Power into low impedance and low to no global feedback is what I hear from
most amplifier advertisements.


OK, so there is another possible differentiator that would be tested for
validity: low/no global feedback vs normal global feedback.

Wouldn't it be nice if we can settle the issue of whether low/no global
feedback sounds any different?

It won't be settled - you cannot prove a negative.


So your real concern with any test is that it does not prove the
negative? How about if you are the testee, and you cannot tell the
difference. Is that good enough for *you*?

While it may not constitute proof to you, to the rest of us if there is
no audible difference between 2 amps with vastly different amounts of
global feedback, then it certainly greatly reduces the significance of
the low/no global feedback claims.

As an engineer, aren't you curious to find out how the amount of overall
feedback affects the sound?

Bromo wrote:

On 4/25/04 12:03 PM, in article , "S888Wheel"
wrote:

Please try to get your facts straight. I said a 6hz tone is useless in
highend.
I still say it's useless for me. I guess Tom finds some use for it. There are
plenty of speakers with adequate bandwidth for the purpose of playing music.
Many of us are not interested in reproducing train wrecks and damaging the
structures of our homes.

Speaking of this - in signal envelope and transients - would the 6Hz
performance be important in an amplifier? I mean, a sharp rising tone might
have a 6Hz component - would it be reflected in this or is there something
else in the amp that would help with signal envelope and transient behavior?

I'm surprised that as an RF engineer you do not see this. A sharp rising
tone will have the higher frequency components. A 6 Hz tone is a really
slow component in the signal.

In a minimum-phase system like a power amp, there is a direct
correspondence between frequency response and time-domain response. You
don't have to ask about transient behavior, unless you are worrying
about slew-rates, or other very large signal effects.

If the rest of the system (the source recording, the CD player, the
preamp, the speakers, etc.) cannot reproduce the 6Hz tones, then it
makes no difference whether the amp can do that or not.

If the rest of the system can reproduce the 6 Hz tones, and you are
interested in listening/feeling it, then of course you want a power amp
that reproduces 6 Hz. That pretty much eliminates all tube amps, and
vinyl systems, by the way.

Bromo wrote:

On 4/24/04 1:03 PM, in article P5xic.20708$aQ6.1263449@attbi_s51, "Nousaine"
wrote:

Given that the amplifiers' ability to drive difficult load is removed -
then
the challenge is removed quite effectively.

Sure and how many "tough" loads are there? Stewart's speakers may qualify
but
of the hunreds of home speakers I've tested I can't recall a single one
(including the 'stats) that would qualify as a difficult load to drive.

Martin Logan has a 1 Ohm impedance at the high end.

I've evaluated a couple of different Martin-Logans and while they do have a low
impedance at 20 kHz and a curve that varies wildly through their operating
range (as does frequency response) I've never had any trouble driving them to
full output with either my bench amplifier or a 100-watt Parasound integrated.

Apogees have a sub 1 Ohm impedance as well.

I have no experience with them.

Thiels are notorious for requiring a lo of current in the bass (and tend to
be 3 Ohms)

I have a Thiel CS-1.6 in house as we speak. While it does have a relatively low
impedance there is nothing at all "tough" about the curve.

Magnepans are -- magnepans and then to have a sub 5 Ohm load.

Same as with the Theil. Indeed Magnepan is noted for claiming a nearly
"resisitive" imdedance curve said to be easier to drive. Of course, that's BS
(it has the typical resisitve, capacitive and inductive qualities just like all
loudspeakers) but the curve is smooth and doesn't vary much over its operating
bandwidth.

All of these are considered to be "difficult" to drive - and many integrated
amp manufactuers place warnings on their amps to not have speakes with
impedances that low!

I've not found this to be the case even with my Un-High-End stable of
amplifiers. Sure a low powered receiver may not have the power to successfully
drive some of these speakers to high output but neither can they do that with
even "easier" loads.

Many times in loud passages the amps could overheat
and trip thei protection circuit - or in extreme cases with no protections,
blow up!

When was the last time you heard of a power ampliifer of any pedigree "blow-up"
when driving a loudspeaker? I've never had an amplifier shut down or blow up
with a hard load that was actually a "load" and not a short. OTOH I've had a
couple high-end models without protection circuitry fry when faced with an
accidental short. The omission of protection circuitry is a design flaw.

But, if you don't see it - feel free to take the "40Wpc into 8 Ohms at 1Khz"
integrated and try to drive a Thiel 7.2....

I'm not so sure I can find a 40watt receiver anymore. I'll dig one up. You
supply the Thiel. :-)


It is true that many autosound enthusiasts like to wire multiple woofers,
often
with multiple coils, in ways that might qualify. But Richard Clark's
challenge
has put the amp sound for autosound to rest as well.

He is trying to prove a negative, so the quest will be forever.

This whole thing struck a nerve - people doing a flashy sort of thing by
putting up a large sum of money with rules constructed so they won't ever be
"wrong"

The whole point of an amp is to source power - and matching that to the
needs of the speaker for good sound reproduction is the big task for that
link in the chain.

Oh please. Finding an amplifier with enough power for a given speaker is not
that difficult. And even in the case of Apogees, most likely the only "tough"
load that I can see here, they are no longer made

This "challenge" has so many if's and conditionals, that it generated more
heat and smoke than light.

It is understood by anyone that if you do not feed the speaker with enough
power, it won't sound good - too much power, and you will blow it out.
Conventional measurements should indicate if the speaker is likely to be
suitable, but to think we understand hearing and the processing our brains
go through to change pressure to sound to make it an end game is pure
arrogance to me!

IMO if there were anything to amp sound that is not readily observable with
traditional measurements and methods then the Richard Clark Challenge should
have brought it to light.

On 25 Apr 2004 14:15:44 GMT, Bromo wrote:

The time and effort might be spent a bit more productively - perhaps trying
to research and measure all sources of sonic imperfections not already known
- pushing the forefront of hearing sciences, and so on.

Actually, since we can already prove that dozens of amplifiers sound
exactly the same below the clipping point, the time and effort would
most definitely be better spent in selecting better speakers, and
placing them in the best position in a well-sorted room.

Of course, this would destroy 90% of 'high end' mythology - but
perhaps the world would be a better place for that............

--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Sun, 25 Apr 2004 17:35:09 GMT, Bromo wrote:

Wouldn't it be nice if we can settle the issue of whether low/no global
feedback sounds any different?

It won't be settled - you cannot prove a negative.

You can however prove that there is *zero* evidence on one side, and
lots of evidence on the other side. Where would *you* place your bet?
--

Stewart Pinkerton | Music is Art - Audio is Engineering