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RE: A contrary test result

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John: I've read the non-refereed preprint you refer to. Though many of their methods are interesting and they went to a lot of trouble, I don't believe the data support the authors' conclusions. They asked their subjects to tell them which sounded more like a multichannel analog feed, a band-limited codec with 44.1kHz sampling, or another with 352.8k. By a small (and statistically insignificant) margin, the subjects thought the 44.1k codec was truer to the source. There were also separate tests with two transmission channels (two sets of microphones and speakers), one with response to 100 kHz and another band-limited to 20k. Again through an unsurprising random statistical variance, the subjects chose the 352k codec *less* often, and the 44.1k codec more often, when there was > 20k audio in the source.

The authors assume (and say so in the paper) that there has to be an audible difference between the codecs, which leads them into a tortured and illogical explanation of how this could have happened. They posit that the ultrasonic material somehow sounded bad, so subjects chose the 44.1k codec when it was present -- but subjects were asked only to say which was more like the (high-bandwidth) source, not which one they liked. So the whole argument kind of collapses in a heap at that point. -- Brad


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