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Re: [ARSCLIST] Ampex ATR-102 opinion (was MD5 Hash Generators
Hello,
Allow me to suggest a practical way to use the scientific method.
When testing a hypothesis of this sort (e.g. "Does de-gaussing a CD make
a difference?"), it may be helpful to distinguish between two types of
results:
(1) We have the metrics to test the hypothesis (e.g. error rates). Then
it is real.
(2) We have a panel of listeners who can test the hypothesis (in a
well-designed blind ABX test).
There are three possibilities for case (2):
(2)(a) All members of the panel can tell the difference. Then it is real.
(2)(b) No members of the panel can tell the difference. Then it is
probably hokum, until proven otherwise.
(2)(c) A subset of listeners (one or more) can consistently tell the
difference. Then you can choose whether that subset of listeners is
large or important enough to justify the expense or work for you.
Unfortunately there are no published tests for everything, so sometimes
you have to perform your own blind test.
As an example, a paper published in the September 2007 JAES ("Audibility
of a CD-Standard A/D/A Loop Inserted into High-Resolution Audio
Playback", by E. Brad Meyer and David R. Moran) seems to prove that
16-bit, 44.1 kHz is indistinguishable from high resolution audio to a
panel of professionals and audiophiles. I am convinced --at least until
someone comes up with a better study debunking this one.
Cheers,
marcos
Bruce Kinch wrote:
On Jan 23, 2008, at 6:28 AM, Jerry Hartke wrote:
Some writers have technical skills, while others spin out profitable
junk
for acceptance by gullible editors and readers.
Full disclosure, I have been an a occasional reviewer for both print
and on-line audio journals. It is not a profitable avocation, and I
have never claimed technical expertise beyond that available to any
informed consumer. I don't consider anyone who investigates any issue
gullible per se, which is unfortunately the frequent opinion of many
who claim special knowledge in any field. That seems arrogant to me.
However, having access to CES and other venues, I have not
infrequently heard effects I cannot easily explain. Not all such
changes seemed to be improvements, and some that were hardly seemed
worth the cost. But then I drive a Mazda, not a Porsche for the same
reason. I have friends who disagree and preferred to pay the
difference. Are they gullible, or just happy?
De-gaussing (there are no
ferromagnetic materials in a disc), polishing (introduces millions of
microscratches that distort the laser beam), and trimming (can worsen
track
eccentricity or unbalance), have the potential to degrade, but not
improve,
CD or DVD disc quality.
The underlying assumption here is that a class of objects produced by
multiple agents at the lowest possible cost will have no functional
flaws that can be remediated after market. The only other consumer
category I can think of that makes such claims would be the purveyors
of religious texts - the Bible, the Qur'an, and whatever the
Scientologists keep by bedside and toilet.
If this remains an issue, Media Sciences would be
glad to participate in a controlled test on a few discs, both before and
after the "improvements", at no charge and then publish the results
online.
Please contact me if you wish to participate.
The logical fallacy here is to equate "disc quality" with the
perception of music. I switched from physics to psychology as an
undergrad because the girls in class were prettier. But I quickly
realized that while the physics lab experiments were straightforward,
experimental psych projects in perception had a lot of independent
variables that could not be controlled. I appreciate that in itself
can drive some people crazy.
Again, there is ample documentation that some but not all auditioners
can and will hear a change from a variety of treatments, tweaks, and
widgets. Some perceive the change as a worthwhile improvement, others
don't. That is normal, not something to get huffy about. If you are
curious about such things, please do look into them.
That this topic keeps re-surfacing, I suspect, is the result of a
certain lingering dissatisfaction among listeners familiar with the
sound of acoustic music in real space with the electronic and and
particularly digital reproduction of that music. The response is
essentially a desire to find something - anything - that will ease
that disappointment. Tom Fine started the discussion by blaming the
engineering, not the technology, for the the problem. I take a broader
view, as I believe the limitations of CD reproduction are obvious in
comparison to higher definition digital as well as analog, to say
nothing of the real thing.
Conversely, many folks (like my kids) who grew up listening to
amplified instruments and entirely digital media have different
criteria. They prize the loud, the clean, and the convenient. Here the
iPod trumps even the CD. The logical extension of a "bits iz bits"
definition of perfect sound is to have the marketplace decide how
much more data can be thrown out and still fool a listener into
thinking it is music.
Bruce