Richard Clark's Amp Challenge

[low_bass_makker]

I was think to start this topic as it is a very debatable topic on many more forums I have visited....

What is this challange?
Has anyone has passed it ?
What are the parameter involved in this test ?
etc.....

I have twiced posted this but I think now body read it....thats why I started this thread. I hope people will show there interest in this topic now....as it is directly related to car amps...

Here are some good read about this topic....

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

http://forum.elitecaraudio.com/showt...6&pagenumber=1

The main thing discussed in this test is ABX on amps....that one can tell which amp is running....hope this thread is a good and healthy discusion...and no fights and ego`s here.....

Navin ji I would be needing your help on this thread.....

[low_bass_makker]

a little more on the challenge


Richard Clark is an audio professional. Like many audiophiles, he originally believed the magazines and marketing materials that different amplifier topologies and components colored the sound in unique, clearly audible ways. He later did experiments to quantify and qualify these effects, and was surprised to find them inaudible when volume and other factors were matched.
His challenge is an offer of $10,000 of his own money to anyone who could identify which of two amplifiers was which, by listening only, under a set of rules that he conceived to make sure they both measure “good enough” and are set up the same. Reports are that thousands of people have taken the test, and none has passed the test. Nobody has been able to show an audible difference between two amps under the test rules.

http://tom-morrow-land.com/tests/ampchall/

[Autophile]

Good you like to believe it LBM. But we have a different take on it. I believe that "watt is a watt" statement is bull****. If you think that statement is right its good for you.

I will give you are comparison which you can do easily in Alpine V12 amplifiers.

340 vs 345
501 vs 605

Leave the power factor alone they are different sounding amplifiers within the brand, I am not even talking about two different brands of amplifier.

340 and 501 are clearly better sounding amplifiers than the current generation counterparts from Alpine.

[low_bass_makker]

I agree watt is a watt it is no bull****

but we have to consider other factors like distrotion clipping freq response.....which differ a good amp for a average amp....

if we compare to amps one is a premium one and the other a average one both played so that the output of both of them is same the average amp might clip but the premium amp might not but when a resistence is connected it will heat it up in the same amount of time when connected to either of the amp it means watt is a watt but it does not lead to that both of them will sound same.....

about the alpine amps reffered above if given a blind test I think anyone would tell us the differnce of the sound if all the parameter of the test are kept constant...like the output clipping, db output, source, etc.....

[Autophile]

Two different amplifiers from different manufacturers with similar specs and power output will sound different.

You need to try yourself with an open mind rather than believing on long pages of text on the Internet.

I have tried in case of Alpines and the 340 and 501 combo sounds much better than the current generation. Rest of the equipment is same, crossovers are set from HU and gains are carefully matched.

[low_bass_makker]

Originally Posted by Autophile

I have tried in case of Alpines and the 340 and 501 combo sounds much better than the current generation. Rest of the equipment is same, crossovers are set from HU and gains are carefully matched.

agree 100% but but but here comes somes variable when did u listened to the first setup with older genration alpine amps and when did u listened to new gen amps...the time difference may be more than 6 months....add to it some more variable like...

1) vehicle acoustics
2) gain matching ( might be differnt as u said matching)
3) Hu setting
4) speaker installation (method , and speaker itself spec variation)
like this many more....

the above challenge is done in a controlled envoirment in which the variable factor is only the amp...and if done a ABX test why till now not a single person has won the challenge....

[Autophile]

LBM, I think I am experienced enough to keep all those factors in mind.

The amplifier test was AB in the same car with same equipment. The only difference was time involved in changing the amps. All the setting Volume, EQ, Crossover were untouched while audition.

Gains were matched carefully and I don't think there is anything else you need to do in the amps with crossover at full range.

The critical comparison of the expensive amps like Audison VRx, McIntosh, Brax etc is done at home using home audio CD Player, Preamp and Speakers. Of course the car poweramps are powered by High Quality 100 A DC power supply.

[low_bass_makker]

Originally Posted by Autophile

The amplifier test was AB in the same car with same equipment. The only difference was time involved in changing the amps. All the setting Volume, EQ, Crossover were untouched while audition.

Gains were matched carefully and I don't think there is anything else you need to do in the amps with crossover at full range.

so i think that u found the differnce and that is ok and if u take a richard test u could really tell the difference were thousand of people could not......just asking.....

[Autophile]

Yes of course, moreover I don't need to follow any Richard Clark test. I know what to look for in amplifier comparison. If you do that in a controlled environment the difference is obvious.

[low_bass_makker]

What were the results of the test?

Nobody has ever successfully passed the test. Richard Clark says that generally the number of correct responses was about the same as the number of incorrect responses, which would be consistent with random guessing. He says in large groups he never observed variation more than 51/49%, but for smaller groups it might vary as much as 60/40%. He doesn't keep detailed logs of the responses because he said they always show random responses.

http://tom-morrow-land.com/tests/ampchall/

[Bass&Trouble]

I'm sure we could all trust me to throw myself into this one. after all, I love controversial threads.

A lot of stuff in there is quite right. A lot of the differences that we could perceive between two different car or intergrated amplifiers could originate because of the quality of other equipment involved or because of the crossover stage, or some other parts that went into the pre-amp etc. Comparing one pure power amp to another pure power amp with truly comparable ratings, and similar power delivery wouldn't allow for much to be discerned unless it was a very very lengthy listening test, and even after that there could be a chance that the two amps still sound identical. No one could tell the difference with a few minutes of A-B testing.

A watt is not a watt, and there is no reason to say that there would be only one amplifier manufacturer then or something. Amplifiers are unique, and with different design considerations. And in car amp, it isn't just the output stage, there are other stages where the quality and choice of parts makes a difference in the sound quality. For example, there are some amplifier manufacturers who wouldn't put rotary crossover adjustment devices in their amps because those could wear over time and not perform as well as modules with fixed resistance that could be added as per need.

Inspite of all this, if the amps are putting out the same power with near equal other charachterisitcs it's going to be terribly difficult to blindly say which is what. Possible certainly, but very very difficult.

If someone asked me what an amp is like, my suggestion is based on the overall charachteristics of the amp and its suitability for the job at hand. An amp said to be better will have better numbers, better build quality etc. this will also mean more power, good quality of parts that don't mess with the sound etc.

Another version of this argument would be someone telling me that they can hear the difference between two identically rated amplifier power cables, or a distribution block or something. Is there anyone who really thinks that?

[low_bass_makker]

Originally Posted by Bass&Trouble

I'm sure we could all trust me to throw myself into this one. after all, I love controversial threads.

Another version of this argument would be someone telling me that they can hear the difference between two identically rated amplifier power cables, or a distribution block or something. Is there anyone who really thinks that?

lol another point is made.....let us see who will able to tell the differnce....

[Autophile]

I never mentioned that power output stage is the only thing in amplifier which contributes to the sound. Everything makes the difference preamp stage, componets like caps, resistors, diodes, pcb, design, materials used etc.

The difference does exist as all these things come in signal path. There are very few pure power amps in the car audio industry. Almost all amps has preamp circuit with or without crossover.

All I mean to say is that different designs sounds different and they does...for sure.

And variable pots are not neccessarily bad. They come in different quality just like the volume knob does (Eg. ALPS is definitely better than regular ones). And crossover are set once while tuning and are left untouched after that, hence no question of wearing.

B&T first of all we have not discussing cables here. And the cables which makes most difference in sound are RCA interconnects not the power cables.

[Autophile]

Originally Posted by low_bass_makker

lol another point is made.....let us see who will able to tell the differnce....

Yeah lot of points are being made...lets say for example "watt is a watt" theory is true and similarly "bhp is a bhp" theory should also be true...right.

So a 100bhp Tata engine should be same as 100bhp Honda engine. Which isn't I believe. They are different in power delivery, available powerband, throttle response, smoothness, torque and power curves, construction, materials, design and even they sound different !!!

If "bhp is a bhp" then people would not have been craving for Honda engines and this forum would not have existed.

According to me Tata and Honda engines are not same. Engine experts on this forum can correct me if I am wrong.

[navin]

If a watt is a watt lets all throw out our Alpines, Audisons, etc.. and get the super value Sony 554/552s instead. LBM would you do the honours! :-)

Seriously....
Bob Carver had once challenged that he could replicate the sound of ANY amplifier using Power Transforms. He conducted this challenge twice.

He modified his amps (at one instance in a local motel room) and voila initially ALL of the listeners were fooled. However on later listening to entire Albums many differences were noted (now this is after Bob had "null-differenced" the 2 amps - his own and another reputed one - to have the same characteristics).

Was the test successful. Yes and No.

Yes becuase Bob was able for 10% of the cost of the reputed amp able to fool a group of hardened experienced audiophiles (if even for a few minutes). Yes becasue the "reference" amps used CV Premier 5 were tubed amps and Carver's contention was that it was the tube amps that had changed (bias shift etc..) and that his SS amp had not changed.

No becuase on long listening tests esp. with musical scores enough difference were noted.

Now wheater one wants to pay 10-20 times more to enjoy these differences solely depends on the purchaser of the amps.

So what did Bob Carver do? well he took his amp and changed the bias, threw in a pair of simple transistors (I believe they were BC 555/556) and a simple resistor etc...but he did make his $500 amp soud alarmingly like a $12,000 Premier 5 and earlier like a $5,000 ML-2.