- Thread Starter
- #241
But this is a distraction. We are still at the point of not being able to say that people don't lose (some) of their audio discerning abilities when they know they are taking part in an experiment. As long as this is true, audiophiles will never believe what your tests show (and, possibly, nor should they). The consensus seems to be that it is "highly unlikely" that we lose our listening abilities, but without any attempt to demonstrate whether it is true or not we cannot know.
My main "problem" with ABX tests is not that I know that I'm being tested, but rather the thing with sensory smearing. It's like my brain smears the sensory inputs all over, and everything becomes a soup where I'm only able to differentiate between the really big things. To really be able to perform well at ABX tests, I think you need to train at it like Amir has done. I know a couple of other Norwegian guys as well, who really take blind testing seriously for their home hifis. They have been able to ABX dacs for example. I'm not even close to doing that.
Anyway, there are people who try to investigate scientifically how different testing procedures work... I recently came across this AES conference paper:
http://www.denismartin.net/wp-content/uploads/2017/01/Martin-et-al.pdf
In scientific diciplines where they employ experiments (i.e. in those disciplines where the papers don't sound like gibberish to me), I often find conference papers to be more valuable than published peer-review papers, due to the publication bias to generate positive findings.
Anyway: A group of researchers from Canada tried to see whether other kinds of tests could reveal differences that simple blind testing could not reveal. In blind tests on audio engineers, the statistical limit for hearing differences between bitrates seems to be 256 kbs - beyond that, it sounds the same to most people when consciously doing ABX-tests. So these guys wanted to see if audio egineers would perform mixing tasks differently when mixing on 256 kbs and 16-bit material, when they didn't know what they were listening to - and didn't know what the experiment was actually about. The hypothesis is that if there are indeed differences here that are perceptually meaningful, then audio engineers will mix in a somewhat different way when mixing on 256 kbs as compared to 16-bit.
They had 27 participants, and didn't find any statistically significant results (that would be difficult with so few participants, I think). Still, the general "direction" of the findings are in line with the hypothesis that there are diffences between 256 kbs and 16-bit which are perceptually meaningful. But the differences were not very large.
My take-away from this study is:
a) that 256 kbs is just fine for listening to music
b) that there probably are perceptually meaningful differences between 256 kbs and 16-bit
c) it lends some very very small support to the theory that ABX test may mask objective differences that may perceived under other circumstances