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Topic: Richard Clark $10,000 Amplifier Challenge (Read 12441 times) previous topic - next topic
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Richard Clark $10,000 Amplifier Challenge

I read through the test conditions and I thought it was strange that EQ was used to make the other amps sound the same.

Richard Clarke's experiments prove TWO things: there are amplifiers that people can easily and reliably distinguish between aurally in a preliminary round (this is a prerequisite for being allowed to do the challenge at his home where you can win the money, and is actually a proof AGAINST what the proponents always claim), and that two amps can be MADE to sound the same.

Thoughts?

Richard Clark $10,000 Amplifier Challenge

Reply #1 –
You know, links and stuff would be useful.

Richard Clark $10,000 Amplifier Challenge

Reply #2 –
Quote from: Rich B on
I read through the test conditions and I thought it was strange that EQ was used to make the other amps sound the same.

Why is that strange?
Audiophiles have been claiming for ages that each amplifier has its own specific sound that is not related to "simple" measurements. Frequency response is the most simple of them all.

If you cannot distinguish an expensive audiophile amp because you made the other amp's frequency response equally messed up, then you've shown that you probably paid a lot of money for non-defeatable, non-configurable, i.e. fixed tone-"controls".

Linear distortion is also trivial to fix. Yes, a proper amp shouldn't exhibit large frequency response deviations (from flat) to begin with, and I'd steer clear of any SS amp that shows a bass or treble boost, but without the EQ I could just take some amp with fixed bass boost compared to a proper (flat) one and win the money 100%.

You have to limit the parameters one way or another, because there are always exceptions. He also could've just dismissed any amp with too large deviations from flat as "broken".
Nonlinear distortion is not as easily fixed, so amps that don't fit within his defined margins are simply dismissed.


Quote from: Rich B on
Richard Clarke's experiments prove TWO things: there are amplifiers that people can easily and reliably distinguish between aurally in a preliminary round (this is a prerequisite for being allowed to do the challenge at his home where you can win the money, and is actually a proof AGAINST what the proponents always claim),

No. The preliminary round uses less trials and is sloppy. It's just a check to see if the person is serious ..

If it proves anything, then that without proper level-matching - surprise, surprise - people hear differences. Said people usually then proclaim that the amps sound different and that they have golden ears. This is some sort of self-delusion that is incredibly persistent within audio.
"I hear it when I see it."

Richard Clark $10,000 Amplifier Challenge

Reply #4 –
Quote from: Rich B on
I read through the test conditions and I thought it was strange that EQ was used to make the other amps sound the same.

Not strange at all. No sane, rational person would claim that an "amplifier" that modifies frequency response, would be indistinguishable for one that did not. And they don't.
Conversely, "audiophiles" will adamantly deny that the EQ imposed by their special effects box is in any way related to audibility signature, just too simple an explanation..and that the reasons are more esoteric and "unknown".
Linearizing these SFX boxes removes the FR deviations variable vs actual amplifiers. That means audiophile must now aurally detect those "unknown" differences, rather than plain 'ol boring FR.

Quote from: Rich B on
Richard Clarke's experiments prove TWO things: there are amplifiers that people can easily and reliably distinguish between aurally in a preliminary round (this is a prerequisite for being allowed to do the challenge at his home where you can win the money, and is actually a proof AGAINST what the proponents always claim), and that two amps can be MADE to sound the same.

Thoughts?

Yes...and no, it isn't proof against what real proponents claim, but perhaps imaginary ones? Like Joe Straw, who claims "All amps sound the same"?

cheers,

AJ
Loudspeaker manufacturer

Richard Clark $10,000 Amplifier Challenge

Reply #5 –
Quote
Why is that strange?


Because it means they clearly don't understand the constraints/reproducibility of the challenge, and that's bad science.

Richard Clark $10,000 Amplifier Challenge

Reply #7 –
Quote from: Rich B on
I read through the test conditions and I thought it was strange that EQ was used to make the other amps sound the same.

Richard Clarke's experiments prove TWO things: there are amplifiers that people can easily and reliably distinguish between aurally in a preliminary round (this is a prerequisite for being allowed to do the challenge at his home where you can win the money, and is actually a proof AGAINST what the proponents always claim), and that two amps can be MADE to sound the same.

Thoughts?


My first thought is that once again, you have failed to either read fully, or have misunderstood what you did read,and have leaped to unwarranted conclusions. DId you, for example, read Richard Clarke's comments about his rules?

My second thought is that no 'proponents' claim 'all possible amplifiers sound the same under all possible conditions'.  NO ONE.  NO ONE says this, RichB.  As you have been told before.  (RichB is on AVSforum too,a s well as Audioholics.)  So why do you repeat this canard?

Amplifiers should not be deviating from flat FR across the audible band.  That is the function of a something called an 'equalizer' or a 'tone control'.  An amplifier that acts as an equalizer might be called something else: broken. It certainly isn't just amplifying.  But in the woolly world of 'high end' who knowswhat poorly-designed jewelry gets sold as having a 'signature sound'?

Richard Clarke is merely making a provision for the most outlandish hypothetical  product...because he knows there's a high end sucker born every minute.

That said, did you ask Richard Clarke how many times he actually had to use EQ to match two amps?  I suspect it is very, very rarely.

Overall *output level* matching, on the other hand, is absolutely necessary for comparing properly-functioning amps.

Richard Clark $10,000 Amplifier Challenge

Reply #8 –
Quote from: JabbaThePrawn on
Bob Carver claimed he could tweak his amplifiers to sound the same as anything on the market. See the 'Amplifier Modelling' section of this page: http://en.wikipedia.org/wiki/Bob_Carver#Amplifier_modeling


Were the amps compared double blind and level matched *before* Carver tweaked one to sound like the other?

If they had been, Stereophile would surely have trumpeted *those* results,  no?

Richard Clark $10,000 Amplifier Challenge

Reply #9 –
Quote from: Rich B on
Quote
Why is that strange?


Because it means they clearly don't understand the constraints/reproducibility of the challenge, and that's bad science.


Who is 'they'?

Richard Clark $10,000 Amplifier Challenge

Reply #10 –
Quote from: krabapple on
I suspect it is very, very rarely.

I agree. He probably almost never needs to invoke the EQ since all competent amps, including dirt cheap receivers, almost always have a nice, flat FR in direct, stereo mode, driving typical loads.

It's also important to note that Clark is willing to place the EQ either on the expensive amp or the cheap amp, whichever the *challenger* chooses. This avoids the argument "But EQs degrade the sound such that the beautiful magic of the expensive amp is degraded by the EQ's junky circuits" [OK, then put the EQ on the cheap amp.]

Richard Clark $10,000 Amplifier Challenge

Reply #11 –
Quote from: mzil on
Quote from: krabapple on
I suspect it is very, very rarely.

I agree. He probably almost never needs to invoke the EQ since all competent amps, including dirt cheap receivers, almost always have a nice, flat FR in direct, stereo mode, driving typical loads.

It's also important to note that Clark is willing to place the EQ either on the expensive amp or the cheap amp, whichever the *challenger* chooses. This avoids the argument "But EQs degrade the sound such that the beautiful magic of the expensive amp is degraded by the EQ's junky circuits" [OK, then put the EQ on the cheap amp.]


Most if not all of his 'tweaking' seems to be in cases where tube amps are part of the comparison.  And again, none of the 'proponents' that RichB  refers to ever said tube amps always sound the same as every  other amp.

Richard Clark $10,000 Amplifier Challenge

Reply #12 –
And btw, the thread title, presumably written by RichB, is another distortion bordering on trolling  -- Richard Clark doesn't say 'all amps sound the same', full stop.

Richard Clark $10,000 Amplifier Challenge

Reply #13 –
Quote from: JabbaThePrawn on
Bob Carver claimed he could tweak his amplifiers to sound the same as anything on the market. See the 'Amplifier Modelling' section of this page: http://en.wikipedia.org/wiki/Bob_Carver#Amplifier_modeling


And Bob Carver did accept and win the Stereophile challenge. If I remember correctly, he won the challenge on two counts: the Stereophile staff ears and an output against output nulling test, which I think was his own objective test of his work.


The most important audio cables are the ones in the brain

Richard Clark $10,000 Amplifier Challenge

Reply #15 –
Quote
Amplifiers should not be deviating from flat FR across the audible band. That is the function of a something called an 'equalizer' or a 'tone control'. An amplifier that acts as an equalizer might be called something else: broken. It certainly isn't just amplifying. But in the woolly world of 'high end' who knowswhat poorly-designed jewelry gets sold as having a 'signature sound'?


But isn't there more to amplifier sound than just a flat frequency response or an altered frequency response? What about harmonic distortion?

Richard Clark $10,000 Amplifier Challenge

Reply #16 –
Quote from: Rich B on
But isn't there more to amplifier sound than just a flat frequency response or an altered frequency response? What about harmonic distortion?


Most modern amps have harmonic distortion well below audible levels unless you drive them into clipping.

Richard Clark $10,000 Amplifier Challenge

Reply #17 –
Quote from: Rich B on
I read through the test conditions and I thought it was strange that EQ was used to make the other amps sound the same.

Richard Clarke's experiments prove TWO things: there are amplifiers that people can easily and reliably distinguish between aurally in a preliminary round (this is a prerequisite for being allowed to do the challenge at his home where you can win the money, and is actually a proof AGAINST what the proponents always claim), and that two amps can be MADE to sound the same.

Thoughts?


If two amps have significant frequency response differences as connected to real world loads (e.g speakers), nobody with an iota of technical knowledge of audio will think that they should or will sound the same.

One or both are acting like equalizers or tone controls and are thus designed to sound different.

If they sound different in a DBT, what knowledgeable person would be surprised? Indeed, if they don't sound different, the test can be scientifically criticized for being insensitive!

The history of audio is that back in the 50s and earlier just about every amplifier had enough technical flaws that it sounded different.

One big step towards amps frequently sounding the same was the advent of properly designed SS power amps in the late 1960s and 1970s. By the late 80s finding amps that sounded the same was pretty easy.

At this point, a very high percentage of all properly designed SS power amps including PA amps, and mainstream AVRs can be reasonably expected to sound the same if you turn of all of their DSP functions.

Making tubed amps that are technically good enough to sound like a good amp, which means it has no sonic imperfections, can take a lot more work and money. But it can be done, especially if you keep swapping the tubes fast enough!

Richard Clark $10,000 Amplifier Challenge

Reply #18 –
Quote from: Rich B on
Quote
Amplifiers should not be deviating from flat FR across the audible band. That is the function of a something called an 'equalizer' or a 'tone control'. An amplifier that acts as an equalizer might be called something else: broken. It certainly isn't just amplifying. But in the woolly world of 'high end' who knowswhat poorly-designed jewelry gets sold as having a 'signature sound'?


But isn't there more to amplifier sound than just a flat frequency response or an altered frequency response? What about harmonic distortion?


Amps don't have harmonic distortion. They have nonlinear distortion, which is sometimes crudely measured using tests commonly called "Harmonic distortion". The only reason why Harmonic Distortion  can work out reasonbly is because most good amps have such low nonlinear  distortion aside from clipping, that they are audibly free of it and often with margins of several orders of magnitude (10x, 100x).

The two most common reasons for non-flat frequency response are DSP functions that intentionally audibly change frequency response, and power amps that can't properly deliver accurate signals to loudspeaker loads.

Loudspeaker loads can also cause some amps to unexpectedly do something that is probably more reasonably described as clipping.

In modern times any amp builder can run out and buy $5 chips that put out enough clean power to be the basis of a pretty good audio system.  I just bought two 300 wpc power amps with balanced I/O and 4 ohm driving capability from a well-known and highly regarded manufacturer for less than $100 each shipped to my door.

That is nature's way of saying that power amps are a solved problem. Next!

Richard Clark $10,000 Amplifier Challenge

Reply #19 –
Quote from: Rich B on
What about harmonic distortion?

What about it? Many types of distortions that could make an amp "audible", THD being the manifestation of some non-linarities.

Quote from: Rich B on
But isn't there more to amplifier sound than just a flat frequency response or an altered frequency response?

Yes. Well accounted for by Mr Clarke if you took the time to actually read what he has said.
Perhaps it's the Joe Straw "All amps sound the same" guy, in his perpetual state of confusion, who is misreading all this?

cheers,

AJ
Loudspeaker manufacturer

Richard Clark $10,000 Amplifier Challenge

Reply #20 –
Indeed, harmonic distortion is the result of nonlinearities on a single tone. In German we call it Klirr as in chink/clank, because if the overtones are loud enough the tone sounds really nasty.
As soon as you apply a second tone (music consists of hundreds and thousands of such tones and noise components ...) the nonlinearities will result in additional harmonically unrelated distortion products. Even nastier.

So of course we'd like to see nonlinear distortion be as low as possible. To make it inaudible, however, you don't need to go to 0.00x% THD although even the lowest-end A/V multichannel receivers for roughly €180 can achieve such low THD+N (including noise!).

Clark says that even 2% THD is very hard to reliably detect. That may indeed be the case with loudspeakers and room acoustics and real music. That's still no excuse to design such horrible amplifiers. Afaik 1% THD is generally considered as clipping point where the power is rated.
"I hear it when I see it."

Richard Clark $10,000 Amplifier Challenge

Reply #21 –
Quote
Amplifiers should not be deviating from flat FR across the audible band. That is the function of a something called an 'equalizer' or a 'tone control'. An amplifier that acts as an equalizer might be called something else: broken. It certainly isn't just amplifying. But in the woolly world of 'high end' who knowswhat poorly-designed jewelry gets sold as having a 'signature sound'?


If speakers can deviate flat in a room, why can't amplifiers? You could argue that most speakers placed in a room is just a complex EQ. So if people use EQ in their systems to taste, why not use amplifiers that alter the frequency response, if it improves their audio experience? If people like what they like, then where is the harm in that?

Richard Clark $10,000 Amplifier Challenge

Reply #22 –
Because by definition alone, an audio amp's job is to linearly amplify audio signals.
If you add distortion then you don't just have an amplifier but also an equalizer or dynamics processor or effects device ...
From a purely technical standpoint, a non-linear frequency response is usually an indicator of bad design like wonky output impedance, incorrectly dimensioned filters, instability, huge amounts of distortion ...

There was also a similar discussion here: http://www.hydrogenaud.io/forums/index.php...st&p=872915 (read the next few posts)


From a practical point of view, you can use a flat amplifier in any system configuration, it is always going to sound the same. But as soon as you start using "broken" amps, that might interact very differently with different loads, you are making your own life harder than it needs to be. You basically start a juggling act that is completely unnecessary.


Preference is another topic. The truth is that the vast majority of people do not care about "broken" amps at all. If they want extra bass then they don't buy an expensive high-output impedance distorting tube amp that will cause bloated, flabby bass, but simply raise the bass slider in their player's EQ.
"I hear it when I see it."

Richard Clark $10,000 Amplifier Challenge

Reply #23 –
Quote from: Rich B on
Quote
Amplifiers should not be deviating from flat FR across the audible band. That is the function of a something called an 'equalizer' or a 'tone control'. An amplifier that acts as an equalizer might be called something else: broken. It certainly isn't just amplifying. But in the woolly world of 'high end' who knowswhat poorly-designed jewelry gets sold as having a 'signature sound'?


If speakers can deviate flat in a room, why can't amplifiers?


Amps "can", but why? Getting fairly linear response out of an amp is not that expensive.
Getting linearity out of speaker and room? That's another thing.
Getting the "right" nonlinearity out of an amp, that corrects (at least partially) speaker/room? Quite a lot of parameters to tweak. Use a DSP.


Quote from: Rich B on
So if people use EQ in their systems to taste, why not use amplifiers that alter the frequency response, if it improves their audio experience?


That's why the amps had "bass" and "treble" knobs, wasn't it?

Richard Clark $10,000 Amplifier Challenge

Reply #24 –
I'm having deja-vu on this thread, I thought all this had been explained to Rich B before?