2. cables
  3. 1118611066

Reviews with all double blind testing?

In the July, 2005 issue of Stereophile, John Atkinson discusses his debate with Arnold Krueger, who Atkinson suggest fundamentally wants only double blind testing of all products in the name of science. Atkinson goes on to discuss his early advocacy of such methodology and his realization that the conclusion that all amps sound the same, as the result of such testing, proved incorrect in the long run. Atkinson’s double blind test involved listening to three amps, so it apparently was not the typical different or the same comparison advocated by those advocating blind testing.

I have been party to three blind testings and several “shootouts,” which were not blind tests and thus resulted in each component having advocates as everyone knew which was playing. None of these ever resulted in a consensus. Two of the three db tests were same or different comparisons. Neither of these resulted in a conclusion that people could consistently hear a difference. One was a comparison of about six preamps. Here there was a substantial consensus that the Bozak preamp surpassed more expensive preamps with many designers of those preamps involved in the listening. In both cases there were individuals that were at odds with the overall conclusion, and in no case were those involved a random sample. In all cases there were no more than 25 people involved.

I have never heard of an instance where “same versus different” methodology ever concluded that there was a difference, but apparently comparisons of multiple amps and preamps, etc. can result in one being generally preferred. I suspect, however, that those advocating db, mean only “same versus different” methodology. Do the advocates of db really expect that the outcome will always be that people can hear no difference? If so, is it the conclusion that underlies their advocacy rather than the supposedly scientific basis for db? Some advocates claim that were there a db test that found people capable of hearing a difference that they would no longer be critical, but is this sincere?

Atkinson puts it in terms of the double blind test advocates want to be right rather than happy, while their opponents would rather be happy than right.

Tests of statistical significance also get involved here as some people can hear a difference, but if they are insufficient in number to achieve statistical significance, then proponents say we must accept the null hypothesis that there is no audible difference. This is all invalid as the samples are never random samples and seldom, if ever, of a substantial size. Since the tests only apply to random samples and statistical significance is greatly enhanced with large samples, nothing in the typical db test works to yield the result that people can hear a difference. This would suggest that the conclusion and not the methodology or a commitment to “science” is the real purpose.

Without db testing, the advocates suggest those who hear a difference are deluding themselves, the placebo effect. But were we to use db but other than the same/different technique and people consistently choose the same component, would we not conclude that they are not delusional? This would test another hypothesis that some can hear better.

I am probably like most subjectivists, as I really do not care what the outcomes of db testing might be. I buy components that I can afford and that satisfy my ears as realistic. Certainly some products satisfy the ears of more people, and sometimes these are not the positively reviewed or heavily advertised products. Again it strikes me, at least, that this should not happen in the world that the objectivists see. They see the world as full of greedy charlatans who use advertising to sell expensive items which are no better than much cheaper ones.

Since my occupation is as a professor and scientist, some among the advocates of double blind might question my commitment to science. My experience with same/different double blind experiments suggest to me a flawed methodology. A double blind multiple component design, especially with a hypothesis that some people are better able to hear a difference, would be more pleasing to me, but even here, I do not think anyone would buy on the basis of such experiments.

To use Atkinson’s phrase, I am generally happy and don’t care if the objectivists think I am right. I suspect they have to have all of us say they are right before they can be happy. Well tough luck, guys. I cannot imagine anything more boring than consistent findings of no difference among wires and components, when I know that to be untrue. Oh, and I have ordered additional Intelligent Chips. My, I am a delusional fool!
tbg
gregadd
574 posts
 
As they say in the neighborhood where I grew up..."it's on now."
Pay attention Pabelson. I did not give a history of DBT which I concede can be a useful tool in revealing prejudices but ignores the real issue. I gave a history of the ABX Comparator. In fact DBT and ABX arrived on the Audio press simultaneously.
You are quite correct Mr. Fremer's results are in fact not a mystery. He proved he could hear the difference.
If you want to know my principal source for the history of ABX it was primarily the Audio Critic written and published by one of the most serious advocates of DBT/ABX Peter Aczel.
Both Mr. Fremmer and myself suffered a personal attack in the letters column. It appaears Mr. Fremmer was not qualified to criticize DBT/ABX because of his sloppy wiritng style. I of course was unworhty because I was a DC trial lawyer.
Like you, when confronted with Mr. Fremers' test results Mr. Aczel refused to acknowledge that Fremer could match A&B to X in a test designed by others, where frequency reponse distortion , output levels,etc. were all accounted for. He tried to wiggle his way out but was unable.
I of course dared to challenge Mr. Aczel to put his money where his mouth was. He was using a top of the line Boulder amp. I offered to trade him his Boulder for the generic Radio Shack amp of his own choice with an equlizer so he could compensate for any frequency reponse violations. In fact I told him he could keep his amp and I would give him the Radio Shack amp of his choice if he promised to use it as a primary reference.
His response was that I knew he could not accept the offer becasue he needed a top qulity amp for his test. He then accused me of conducting a cheap trick. He said this trick may work on a DC jury but not on him. This transpired in the late'70's or early '80's. Harry Pearson published the first letter in the absolute sound.
Pableson while I may make mistakes, I don't indulge in falsehoods.
tbg OP
5,263 posts
 
Pabelson, you owe us an explanation of how two amps that replicate music differently can sound identical in the restrictions of DBTesting.
pabelson
344 posts
 
Gregadd: If you were talking about the response of a single objectivist, you should have named him right up front. Instead, you tagged all objectivists as dishonest, based on your interactions with one man. That's an understandable error, but it's an error.

There have been dozens of published DBTs of amps. Some have been positive, some have not. Fremer claims to have done a positive test. So what? He ain't the first, and won't be the last.

I'll pose to you the question I've posed to others: Shouldn't a reviewer, before he reviews an amp, confirm that he really can hear a difference between this amp and his reference amp when he doesn't know which is playing? Ever wonder why none of them do this?
pabelson
344 posts
 
TBG: Two amps that reproduce music differently enough to be heard will NOT sound identical in a DBT. But how do we know that two amps reproduce music differently? You say they do, but how do we know you are right?

Let me pose the question a bit differently. Here we have two amps that are not distinguishable in a level-matched, quick-switching ABX test, generally regarded in scientific circles as the gold standard for determining audible differences. A subjectivist claim that these two amps reproduce music differently. How would he prove that they do? Whatever he does, he has to use a blind test, because a sighted test can prove nothing about audibility. That's settled science. So what kind of test should he use?
qualia8
49 posts
 
The standoff between Pabelson and Tbg reminds me of the stalemate between the external-world skeptic and the dogmatist.

Skeptic: You don't know that you're not a brain in a vat of nutrients, being stimulated by a computer simulation, carefully monitored by a team of scientists, to think you're in a real, concrete world... the world you *think* you're in. Since you don't know you're not a brain-in-a-vat, you don't know anything mundane about the external world, e.g., that you have two hands.

Dogmatist: I know I have two hands! If I know I have two hands, then I know I am not a handless brain-in-a-vat. Therefore, I know I am not a handless brain-in-a-vat.

One man's modus ponens is another man's modus tollens, as the saying goes.

(For non-logicians, modus ponens is: If P then Q. P. Therefore Q. Modus tollens is If P then Q. Not-Q. Therefore, not-P.)

Pabelson: DBT shows no audible difference between cables, therefore there is no audible difference.

Tbg: There is an audible difference between cables, therefore, DBT is flawed.

Logic alone (formal logic) cannot settle the dispute, any more than logic can settle the skeptic/dogmatist dispute.

But in this case, it's odd to think of Tbg's favored cables being a/b'ed with cheapos, without his being able to tell the difference, and then, only when told the true identity of the cables, his insistence that there *is* a perceivable difference. Very odd.

Here's a question for the doubters of DBT-ing. Given that there are perceptual biases at work (expectation, confirmation, endowment effect, etc.) how would one test for such biases? That is, what *would* count as two components sounding the same?

Suppose you have two amps that are identical except one of them has a beetle put inside and the beetle runs around, I don't know, defecating in there. And then reviewers praise the beetle effect: "Widened the soundstage by meters! You don't need golden ears to hear this one!" How would you go about evaluating the beetle effect?
More to discover