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$10k golden ears AMP challenge!


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#1 of 1046 glen donald

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Posted October 31 2002 - 03:46 PM

To call Richard Clark an audiophile would be a huge understatement, his strong EE background has enabled him to work with some of the finest audio equipments available to man. He is believes the quest for better sound should be through research based on “scientific facts”. It’s this passion that leads him to believe that the audio world is full of “marketing BS” and there are too many “fools” who purchase with their eyes rather than ears – particularly AMPLIFIERS.

While he believes all amplifiers are different, however the differences aren’t necessarily noticeable through human ears. He has been challenging the “big guys” who sell “big amps” for many years, his motto is “prove to me what you say your amps can do and I’ll buy them..”.

The challenge requires a person to tell the difference between two ampliers in an A/B listening test, 12 times in a row. If successful, you win his $10k – but if you loose, you walk away with nothing but wounded pride.

The challenge has been around for many years, originally was for Car audio amplifiers, today he feels the “the marketing BS in home audio is deeper” so he challenges any home audiophile to the A/B test. ALL COMMERCIAL amps are permitted for the test, that means you can bring your “super tube” amp and he’ll test it against a “budget” solid state amp (e,g Panasonic, Pioneer) or any combinations of amps you can think off, as long as it is commercially available, it’s accepted.

For those who think Car amps are “not the real stuff” compared to home amps, if you like, you may test your super home amp against one from the car audio world (you get to pick all the amps too). If you can tell the difference between two amps, you win $10K.


The rules will be on the next posts of this thread; read it thoroughly – once you do, you’ll see that this test is more than fair and there is no hidden “traps” at all.

contd next post......

#2 of 1046 glen donald

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Posted October 31 2002 - 03:47 PM

INTRODUCTION

THE $10,000 AMPLIFIER CHALLENGE RULES {April 21, 2000}
By Richard Clark

There is no question that all amps are not the same. It is very easy to measure large differences in the performance of amplifiers. This is true in nearly every known specification, including power, noise, distortion, etc. My experience has led me to believe that even though these differences can be easily measured, hearing those differences may not be so easy. Given the relatively small magnitude of performance differences, there is a giant step between amplifier performance and our ability to hear performance differences.
It is claimed by designers, manufacturers and especially salespersons that differences in amplifiers are clearly audible. Reasons include "obvious" advantages of one type of circuit topology over another. For example, it is claimed that certain designs have a smoother midrange response whereas other amplifiers exhibit tighter bass. Tube fanatics claim that tube amplifiers have that "warm" sound we all need in our systems.
Such descriptive terms are certainly subject to personal interpretation. It is not my intention to determine if one particular amplifier is better than another amplifier. Differences in the quality of the discrete components and constructions are more appropriate for settling the issue of "good - better - best." The sole purpose of my amplifier challenge is to determine if the differences in amplifiers are audible.

What differences are Audible?

I believe the perceived differences in amplifiers are all due to various factors that can be explained with basic physics and elementary psyco-acoustics. For instance, if two amplifiers are not carefully matched in volume, and one amp is slightly louder than the other, then it would be a simple matter to detect such a difference. In such an example it is important to understand that it is not the circuit topology, quality of the component, design excellence, or superb marketing and packaging that caused the noticeable difference - it was an error in the test setup! It is my present belief that as long as a modern amplifier is operated within its linear range (below overload), the differences between amps are inaudible to the human ear.

Comparing Amps

The idea here is for a test subject to scientifically demonstrate his/her ability to hear differences in amplifiers. It is our job to carefully match the amps so that we are comparing "apples to apples" instead of "oranges to frogs." This means that we sure wouldn't want to compare one amplifier that had + 12 dB of high frequency boost against another amplifier that was adjusted for + 12 dB of bass boost. Such a test would be easy to pass - even on identical amplifiers with consecutive serial numbers.
For our comparison test, we aren't concerned with which amplifier sounds best to the test subject. We only require that the listener be able to identify each amplifier when it is powering the speakers. Since many folks seem to believe that amplifiers have some kind of distinctive sonic character, this test should be easy to pass. Right? After all, we're talking about comparing those harsh sounding, high distortion, squeaky "widget As" to those warm sounding, smooth, bass hog "widget Bs."
Now pay particular attention to the following sections. Since we're looking for differences in amplifiers, and we already know that those differences are probably going to be very, very small, it is important that the parameters under our control be carefully adjusted so as to be equal as possible. This means that we must be cognizant of differences we might unknowingly introduce between amp A and amp B. They must be adjusted as identical as possible. We already mentioned the importance of volume. The same goes for the L and R balance. It sure would be easy to choose an amplifier that exhibited left side bias over a balanced amp. Right?
Well, in order to keep this amplifier comparison test fair, there are a few other parameters that must be considered. I'll list them all in the following section.

Cont'd mext post.........

#3 of 1046 glen donald

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Posted October 31 2002 - 03:48 PM

TEST CONDITIONS


Amplifier Comparison Test Conditions

1. Amplifier gain controls - of both channels - are matched to within +- .05 dB.

2. Speaker wires on both amps are properly wired with respect to polarity. (+ and -)

3. That neither amp has signal phase inversion. If so correction will be made in #2 above.

4. That neither amp is loaded beyond its rated impedance.

5. That all amplifiers with signal processors have those circuits bypassed. This includes bass boost circuits, filters, etc. If frequency tailoring circuits cannot be completely bypassed an equalizer will be inserted in the signal path of one (only one and the listener can decide which) of the amps to compensate for the difference. Compensation will also be made for input and output loading that affects frequency response. Since we are only listening for differences in the sonic signature of circuit topology, the addition of an EQ in one signal path only should make the test even easier.

6. That neither amp exhibits excessive noise (including RFI).

7. That each amp can be properly driven by the test setup. Not normally a problem but it is theoretically a problem.

8. That the L and R channels are not reversed in one amp.

9. That neither amp has excessive physical noise or other indicators that can be observed by the listener.

10. That neither amp has DC OFFSET that causes audible pops when its output is switched.

11. That the channel separation of all amps in the test is at least 30 dB from 20Hz to 20kHz.

In addition to these requirements the test will be conducted according to the following rules.

cont'd next post........

#4 of 1046 glen donald

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Posted October 31 2002 - 03:49 PM

RULES

Amplifier Test Comparison Rules

1. To make things easy we would prefer to use high quality home type loudspeakers for the test. If our speakers are not acceptable, the listener can provide any commercially available speaker system as long as it uses dynamic drivers. The actual measured impedance cannot exceed the rated load impedance of the amplifiers tested. If, however, the tester would like to perform the test in a car, we will use a car, however, it will have to be provided by the test subject. For practicality we will have to limit the number of amplifier channels to four or less.

2. Amplifiers will be powered from the same power supply at a nominal 14 volts DC. (any voltage is OK as long as it is the same for both amps)

3. The test can be conducted at any volume desired; however, the amps will not be allowed to clip. In other words, listening volume can not exceed the power capacity of the smallest amp of the pair being tested. (power capacity will be defined as clipping or 2%THD 20Hz to 10kHz, whichever is less)

4. No test signals can be used - only commercially available music.

5. The listener can compare two amps at a time for as long as desired. For practical reasons we would like to keep this at least no more than a few hours. A test session will consist of 12 A/B sequences. Passing the test will require a positive identification of each amp for all 12 sequences. Remember, guessing will get you about 6 out of 12. If the differences are so great, and a subject can really hear the difference, then he/she should be able to do so for all 12 sequences.

6. To win the $10,000.00, the listener must pass two complete sessions of 12 comparisons. Passing the test means 24 correct responses.* The amp of choice can be compared to the same or a different amp in each session - challengers choice. We have many amplifiers in our demo inventory such as, but not limited to, Alpine, Rockford, Kicker, Phoenix Gold, Precision Power, MTX, Adcom, Kenwood, Pioneer, Sony, etc. You can pick any of them or bring your own.

7. All amps must be brand name, standard production, linear voltage amplifiers. This does not exclude high current amps. Amps can not be modified and must meet factory specs. They must be "car audio amplifiers designed to be powered from a car's electrical system."

8. Failure of an amp (this includes thermal shutdown) during the test will require that the test be repeated after repair or replacement or cooling of the amp. This means that the entire test session will have to be repeated.

9. The amps will not be overloaded during the session from either a voltage or current requirement.

10. To save time the listener will have to pass a quick 8 trial session to qualify for the extended 2 session test for the money prize. Any 2 amps can be used for this test. Passing this qualifying test will require at least 6 out of 8 correct answers.

11. The amplifier power up and/or power down sequence will not be acceptable for comparison. (The turn on/off noises of some amplifiers would give it away.)

12. Although anyone is welcome to take the test, only subjects employed in the car audio industry or Car Sound subscribers are eligible for the $10,000.00 prize.


13. Cost to take the test is $100.00. $300.00 for people representing companies. Payable in advance, scheduled appointments only. Done correctly the test takes several hours and I don't have the time if you aren't serious.


cont'd next post...........

#5 of 1046 glen donald

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Posted October 31 2002 - 03:51 PM

WHAT IT TAKES TO WIN $10k


* Twelve correct responses in a row is certainly a lot of correct listening but $10,000 is also a lot of money for a few hours of easy listening. The way people describe the differences is that they are like night and day. I would certainly not have any trouble choosing between an apple and an orange 12 times in a row. When compared fairly I believe the differences in amps are much too small to audibly detect and certainly too small to pay large sums of extra money for. If I am wrong someone should be able to carefully take this test and win my money. Even if I am right, if enough people take the test eventually someone will take my money due to random chance. This is the reason for the large sample requirement. If you feel that you can easily pass this test but 12 sequences will give you "listening fatigue" I am willing to modify the requirements. Since the way it is being offered is a challenge and only my money is at risk I am willing to let a confident challenger "put his money where his ears are". If we are willing to make this a bet instead of a challenge, I am willing to drop 1 sequence for every thousand dollars put up by the challenger against my money. This would mean:


____My___________ _ _Your________Trails Required to win__
$10,000 to $0 = 12 Tries
$9,000 to $1,000 = 11 Tries
$8,000 to $2,000 = 10 Tries
$7,000 to $3,000 = 9 Tries
$6,000 to $4,000 = 8 Tries
$5,000 to $5,000 = 7 Tries
$4,000 to $6,000 = 6 Tries

I will not do the test with less than 6 trails. It would be statistically meaningless and reduce the challenge to mere gambling


end of Rules and Conditions
--------------------------------------------------

#6 of 1046 glen donald

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Posted October 31 2002 - 03:52 PM

So those who say their "very expensive amp" sounded better than the "average made in china amp", take the challenge and pocket yourself $10KPosted Image

His forum is located at carsound.com:

He loves a good debate on Audio, especially if you have strong background in Electronics engineering, don't be shy to voice your disagreementPosted Image

http://www.carsound.....1;t=019632;p=2

#7 of 1046 kevitra

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Posted November 01 2002 - 06:39 AM

This was discussed quite a bit at avsforum a few months ago.

here

#8 of 1046 JaleelK

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Posted November 01 2002 - 07:32 AM

Quote:
So those who say their "very expensive amp" sounded better than the "average made in china amp", take the challenge and pocket yourself $10K


You would think you would have people knocking down your door to take this challenge. Especially in this forum with will all the "Krell blows away Denon" type post.

#9 of 1046 Chu Gai

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Posted November 01 2002 - 08:14 AM

Well Sylvia's not chomping at the bit to win the $1 million Randi prize either. Maybe a Stereophile reviewer will jump at the chance and donate the proceedings to some worthwhile charity.

#10 of 1046 Seth_L

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Posted November 01 2002 - 08:38 AM

Quote:
Well Sylvia's not chomping at the bit to win the $1 million Randi prize either. Maybe a Stereophile reviewer will jump at the chance and donate the proceedings to some worthwhile charity.
You're of course assuming that they could pass this test.

Seth

#11 of 1046 randy bessinger

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Posted November 01 2002 - 08:39 AM

Quote:
Well Sylvia's not chomping at the bit to win the $1 million Randi prize either. Maybe a Stereophile reviewer will jump at the chance and donate the proceedings to some worthwhile charity.


Never happen-too much ego at stake.

#12 of 1046 John Kotches

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Posted November 01 2002 - 10:11 AM

Let's see.

Two tests, at 12 iterations each. That's 24 iterations. Preliminary test to get to the "real test" is 6 of 8. THis means a winner will have 30 of 32 correct responses.

Anyone that knows much about the application of an A/B test will tell you the format is designed to make the person invoking the test win. Even clinical trials of medications (where a lot more is at stake than an individual's ego) don't have to meet a 30 out of 32 criteria for efficacy vs. placebo.

Also, usage of Krell and Denon amplifiers are both excluded.

7. All amps must be brand name, standard production, linear voltage amplifiers. This does not exclude high current amps. Amps can not be modified and must meet factory specs. They must be "car audio amplifiers designed to be powered from a car's electrical system."

Regards,
Surround Music Enthusiast / Curmudgeon in Training
Opinions are my own, not representative of the publication I write for.

#13 of 1046 Chu Gai

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Posted November 01 2002 - 10:26 AM

well gee John, there are people who say they hear differences between dozens of amps, each with their own signature. certainly a discerning palate such as that would have no trouble choosing two quite dissimilar amps?
but aside from that, i believe the proponent of the test is looking to obtain a certain statistical confidence level. If we drop the confidence level to say 1 sigma, 66% i believe, less correct answers would be required. clinical trials for medicinal effectiveness have different goals.

#14 of 1046 Andre D

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Posted November 01 2002 - 10:32 AM

Quote:
Also, usage of Krell and Denon amplifiers are both excluded.


Where does it say that Krell and Denon amplifiers are excluded?

#15 of 1046 Saurav

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Posted November 01 2002 - 10:49 AM

Quote:
Compensation will also be made for input and output loading that affects frequency response.

Interesting. Impedance interactions between the amp, the cables and the preamp's output are one possible reason for why two amps may sound different in one specific system.

Does he talk about the hookup and switching mechanisms? I'm curious about that too - many amps don't have gain controls, so the preamp will need to be set at different levels for the two amps. Also, one should drive both amps with the same source and preamp, and certainly drive one set of speakers (since moving the speakers by a foot or so can change the sound enough to make them distinguishable).

Where is this test being conducted? Who pays for airfare? Posted Image How long ago was this offer/bet/challenge made? How many people have tried it so far? I'm assuming no one has succeeded yet.

Quote:
Amps can not be modified

There go my amps then Posted Image

#16 of 1046 Michael Roderiques

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Posted November 01 2002 - 12:16 PM

Who really cares.
Just not enough money to make it worth while.

I guess I am just an old school type

If you like the sound, and thats what sounds good, then it sounds good and you like it, so its good.

I just can't see putting all this effort into a automotive sound system. A car has so much noise that it just is not worth it to me.
Michael Roderiques

#17 of 1046 John Kotches

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Posted November 01 2002 - 01:41 PM

Andre,

I quoted the portion (#7 in one of the posts) which says this is for car amplifiers only.

I quoted to save everyone from wading through the multiple posts, apparently to no avail.

Regards,
Surround Music Enthusiast / Curmudgeon in Training
Opinions are my own, not representative of the publication I write for.

#18 of 1046 John Kotches

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Posted November 01 2002 - 01:47 PM

Chu,

The test is built in the designers favor. Of course if it was my US$10K, then I'd do the same thing myself.

Dictating choice of speakers drivers (an important real world consideration), compensating for load differentials (also important real world consideration) are taken out.

So as long as we duplicate all the conditions for any amplifier we purchase, they'll all sound the same.

Further, the conditions posted state this is for car audio amplifiers.

Regards,
Surround Music Enthusiast / Curmudgeon in Training
Opinions are my own, not representative of the publication I write for.

#19 of 1046 Seth_L

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Posted November 01 2002 - 02:35 PM

John,

He has since extended the offer to home amps as well. But we know you wouldn't dare take him up on his offer. You have too much to lose when he proves you can't tell a tube amp from a Pioneer reciever.

Instead you will argue about statistical signifance and sigma and how the test is flawed... blah... blah... blah...

Seth

#20 of 1046 Andre D

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Posted November 01 2002 - 03:13 PM

Quote:
Further, the conditions posted state this is for car audio amplifiers.


The challenge includes both car and home amplifiers. He will even do a car vs. home if you choose. You can pick which ever speakers you want. He will even let you use headphones if you want.


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