Re: Red Meat again

On Wed, 15 Feb 2006 00:18:16 GMT, <nyob123@xxxxxxxxxxxx> wrote:

Read this over on RAHE, I knew some of you would just love to read it if you
have not done so already. :-) From Bob Marcus.

Enjoy.

"A perennial claim holds that much of what objectivists think they know
about
audio is wrong because they rely on short-term switching comparison tests,
whereas audiophiles and reviewers evaluate components by listening to a
single system over the course of days or weeks. When challenged to produce
evidence that the latter method is more reliable, subjectivists insist that
a true comparison of the two approaches is too cumbersome to perform--though
they would hope that someone would do it for them some day!

Well, it turns out that somebody has, more than once, and the results don't
look good for the subjectivists. This is, admittedly, old news, though it's
largely new to me. And since the argument keeps coming up (most recently in
the Perception thread), I thought it would be useful to lay it out in full,
so we have it to refer to in the future.


Experiment #1 was conducted by David Clark and Lawrence Greenhill in the
late 1980s. Clark rigged up two black boxes. One was a straight-wire
pass-through. The other added 2.5% harmonic distortion to the signal.
Members of two audiophile clubs were given one of the boxes to place in
their own systems for an extended period, and asked to report back on
whether they thought they had gotten the straight-wire box or the distorting
box. Results were null. In a quick-switching ABX test, however, subjects
were able to tell the difference between a clean signal and one with 2%
distortion added.


Experiment #2 was conducted by Tom Nousaine in 1996. He prepared two sets of
CD-Rs. One set of CD-Rs was a bit-for-bit copy of a commercially released
song. The second set added 4% harmonic distortion to the song. He mailed the
disks to 16 audiophiles and asked them whether they had received a clean
disk or a distorted disk. Again, results were null. He then administered an
ABX test to one of the subjects who had gotten it wrong. Using a looped
6-second extract of the song, this subject was able to score perfectly.


Three important points about the subjects in the long-term portion of these
experiments:
1) They were able to listen in their own system.
2) They were able to listen over extended periods. (Most of Nousaine's
subjects, for example, kept the disk for 3 weeks or more.)
3) They were able to listen to and evaluate a single presentation, rather
than directly comparing different presentations.


No listening test with a null result can ever be definitive, but these two
experiments provide solid data supporting the use of short-term switching
tests for audio comparisons and indicating the inappropriateness of the
long-term single-presentation method of evaluating audio equipment.
Furthermore, they demonstrate that comparisons of the two methods are
practical. Complaints about the complexity of such comparisons are empty
excuses. And no defender of the subjectivist faith has ever produced a
single experiment demonstrating that long-term single-presentation
evaluations are more sensitive that short-term switching comparisons for
detecting anything.


Finally, it should be noted that neither of these experiments represented
ground-breaking science. Psychoacoustics experts have long known that our
memory for partial loudness differences is very short (on the order of
seconds), and that any test which does not allow for direct comparisons will
likely produce a null result. Clark, Greenhill, and Nousaine merely
confirmed this using audiophile ears and systems."


bob

So?

Not only did they represent "ground-breaking science", they really
didn't represent science at all. Just anecdotal wishful stories.

Were's scientific rigor when you need it?

<chuckle>
.

Relevant Pages

  • Re: Red Meat again
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  • Re: Red Meat again
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