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
Pabelson, I completely agree with you with respect to DBT, but then I completely disagree with you that all CD players and amps that are competently designed sound alike.

This is simply not what I hear, and there are good reasons that amps and CD players sound different. Power supplies for one. Good power supplies cost money. Potentiometers in amps ... good ones cost money.

Inexpensive CD players do sound remarkably good these days, and the turntable days of source first are not quite so applicable, but to state that amplifiers are all alike makes me wonder which ones you have has the opportunity to listen to.

No I have not performed DBT on amplifiers, but I have had several occasions where an amplifier that I would have expected to sound excellent (usually on the basis of reviews) sounds markedly inferior to another amplifier that has received much worse reviews, and does so on a range of speakers.
Sean T.: If you believe in DBTs, then you have to believe in the results of DBTs. Some years ago (I can get details if you want), Tom Nousaine delivered a paper at an AES conference in which he sumarized the results of about two dozen published DBTs of amplifiers. Of those, only five reported statistically significant positive results. One involved a comparison of 10-watt and 400-watt amps, so clipping distortion was a likely cause. Two others involved a misbiased or oscillating tube amp. One author simply tossed out 25% of his results. And the fifth involved amps with reportedly large frequency response differences.

In other words, amps can sound different, but 1) they usually don't; and 2) when they do, there is a very good and easily measurable explanation. If you can distinguish two amps with flat frequency response and low distortion in a blind test, you will be the first. And most amps today have flat frequency response and low distortion, at least when they are not driven beyond their capabilities.
Pabelson, you say, "If you can distinguish two amps with flat frequency response and low distortion in a blind test, you will be the first." This means one of two things: there is no differences among amps or DBTesting does not allow humans to judge the differences. To accept the formerr means that quality parts, innovative power supplies, careful construction, and generally good design contributes little or nothing and that humans are hopelessly delusional.

As I have posted, I very much suspect the methodology is invalid. In the research that I do, I cannot imagine peers to accept a methodology that so often accepts the null hypothesis that nothing matters. Since my research so often suggests that states enacting seatbelt laws, .08 alcholal level as intoxicated, spending more per capita on education to compete with other states, or to allow concealed handguns all have no effect on the problem to which they are directed, I know the rath concerning my methodology, which unfortunately cannot include an experiment where have of the states randomly drawn have a law or action, and the other half do not. Here many want to accept that governmental actions matter. In audio many want to accept that amps don't matter. I think other methodologies should be used to assess both prior convictions.
"If you can distinguish two amps with flat frequency response and low distortion in a blind test, you will be the first." This means one of two things: there is no differences among amps or DBTesting does not allow humans to judge the differences.

No, TBG, it only means that the differences are not sufficient to be audible by human ears. Read the data, or supply your own. As of now, your only argument seems to be, "I don't believe it, so it can't be true."

As for DBT methodology, it is accepted by everyone in the field of perceptual psychology, in part because it gets plenty of positive results. It just doesn't always get them in the narrow category of high-end audio, because high-end audio has more than its share of snake oil.

Finally, there's a difference between a "delusion" and an "illusion." Look it up.
Btw,Tbg, like your former self, I am a modestly paid Assistant Prof. who would dearly love to subsist on cheap electronics. Right on the mark!

What do you think of my suggested experiment? Not blind, but with deception alternated with truth-telling about the values of the cables played?

And Pabelson: do you know if an experiment like this has been performed? I have grad student friends in psych who could do it pretty easily. But there's no point if it's already been done.