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
In theory, I like the idea of double blind testing, but it has some limitations as others have already discussed. Why not play with some other forms of evaluating equipment?

My first inclination would be to create a set of categories; such as dynamics, rythm and pace, range, detail, etc.. You could have a group of people listen and rate according to these attributes on a scale of perhaps 1 to 5. You could improve the data by having the participants not talk to one another before completing their ratings, by hiding the equipment from them during the audition, and by giving them a reference audition where pre-determined ratings are provided from which the rater could pivot up or down across the attributes.

Yet another improvement would be to take each rating category and pre-define its attributes. For example, ratings for "detail" as a category could be pre-defined as: 1. I can't even differentiate the instruments and everything sounds like a single tone. 2. I can make out different instruments, but they don't sound natural and I cannot hear their subtle sounds or noises. 3. Instruments are well differentiated and I can hear individual details such as fingers on the fret boards and the sound of the bow on the violin string. Well, you get the picture. The idea is to pre-define a rating scale based on characteristics of the sound. Notice terms such as lush or analytical are absent because they don't themselves really define the attribute. They are subjective conclusions. Conceivably, a blend of categories and their attributes could communicate an analysis of the sound of a piece of equipment, setting aside our conflicting definitions about what sounds 'best', which is very subjective. Further, such a grid of attributes, when completed by a large number of people, could be statistically evaluated for consistency. Again, it wouldn't tell you whether the equipment is good or bad, but if a large number of people gave "detail" a rating of #2 and you had a low deviation around that rating, you might get a good idea of what that equipment sounds like and decide for yourself whether those attributes are desireable to you or not. Such a system would also, assuming their were enough participants over time, flush out the characteristics of equipment irrespective of what other equipment it was used with by relying upon a large volume of anecdotal evidence. In theory, the characteristics of a piece of equipment should remain consistent across setups or at least across similar price points.

Lastly, by moving toward a system of pre-defined judgements one could create some common language to rating attributes. Have you noticed that reviewers tend to use the same vocabularly whether evaluating a $500 piece of gear or a $20,000 piece of gear. So, the review becomes judgemental and loses its ability to really place the piece of gear in the spectrum of its possible attributes.

It's not a double blind study, but large doses of anecdotal evidence when statistically evaluated can yield good trend data.

Just an idea for discussion. If you made it this far, thanks for reading my rant :).

Jeff
My apologies. I took you for the typical DBT-basher. As for amps, assuming you are talking about solid-state amps designed to have flat frequency response, I seriously doubt it matters (in a DBT) what preamp you use, or how expensive it is. If it has the power to drive your speakers, it will sound like any other good solid state amp with enough power to drive your speakers. Or so the bulk of the research suggests.

To your final point, I'm not sure what's in Mr. Porter's system, but the Nousaine experiment at least suggests that he would NOT notice such a swap, assuming you could finesse the level-matching issues. That's not to say that Mr. Porter's system is not right for Mr. Porter--merely that it might be possible for someone else to achieve a Porter-like sound for somewhat less money. And swapping out amps and cables is one thing; I wouldn't even dream of touching his turntable!
I find this a very interesting topic.

On one hand, it is somewhat accepted that the perfect component imposes no sonic qualites of it's own on the passing signal, but yet voicing of components is often referred to - particularly in the case of cables.

So, if a component is purposely voiced, then the reproduction cannot be true to the source can it? Further, if the differences are so obvious as many anecdotally state, it should be no problem to pass BT, DBT, or ABX tests...
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I have a huge problem with the concept of DBT, with regards to trying to determine the differences or lack there of, with audio products. Maybe I'm just slow but, I often have to live a piece of gear for awhile before I can really tell what it can and cannot do.
DBT is great for something like a new medicine. However, it would be worthless if you gave the subjects one pill, one time. The studies take place over a period of time. And that is the problem with DBT in audio. You sit a group of people in front of the setup. They listen to a couple of songs, you switch whatever component and then play a couple of songs. That just doesn't work. The differences are often very subtle and can't be heard a first.
Which, of course, is the dilemma of making a new purchase. You have to base your decision on short listening periods.
The concept of a DBT for a audio component is great. But, I have yet to see how a test would be set up that would be of any value. Looking a test results based on swapping components after short listening periods would never influence my buying decisions. I wouldn't care how large the audience was or how many times it was repeated. Anymore than I would trust a new drug that was conducted with a one pill dose.