On Fri, 04 Jul 2003 17:40:00 GMT, (ludovic
mirabel) wrote:

Darryl Miyaguchi wrote in message ...
On 1 Jul 2003 15:10:59 GMT, (ludovic mirabel)
wrote:

Apologies for rearranging your text for my convenience.
You say:
In my opinion, there are two topics which should not be mixed up:

1) The effectiveness of DBT's for determining whether an audible
difference exists
2) The practical usefulness of using DBT's for choosing one audio
producer (component or codec) over another.

Let me be quite brutal about this.
My ONLY concern and interest is in part 2. I'm reading and
participating in RAHE not because I'm interested in psychometric
research but exactly for help to "choose one audio producer over
another". And the "producer" that I'll use in my listening room is
not codec but a musical reproducing device.

Your claim is that DBT's reduce the ability to discriminate
differences in music using audio components. This is a very specific
claim which relies upon several assumptions:

1. DBT's reduce, in general, the ability to discriminate differences.

Some evidence to the contrary:

ABX has been successfully used to differentiate truncation vs.
dithering at 16 bits:

http://ff123.net/24bit/24bitanalysis.html

ABX has been successfully used to discriminate volume differences in
music of less than 0.5 dB (personal tests).

2. ABX may be ok for pink noise, but not for music.

A controlled test (Greenhill's) showed decreased listener sensitivity
when choral music was presented instead of pink noise. From this you
infer that ABX is not suited for music. Again, I must point out that
this inference is flawed. The simpler and more likely explanation is
that all types of listening methods (included sighted listening) are
affected by musical selection.

3. DBT's may be ok for audio codecs, but not for comparing audio
components.

We seem to disagree on this basic point, although I will point out
that you can hardly claim that the onus is on me to provide evidence
that the two situations are similar. If I assume a certain position
(that the human ear/brain behaves similarly, according to the same
psychoacoustic descriptions, regardless of the audio source), then
your position is surely an assumption as well, and IMO more
speculative. I choose the null hypothesis (there is no difference)
until I see evidence to the contrary.

Sorry, but the questiion is a simple one :"Did THIS panel perform
differently on pink noise and music or not?"
And the answer should be simple: Yes or No. Once you answer that you
can give your qualifiers, explanations and so on..

See my separate post to this.

cut

3. DBT's in general may be decreasing the ability to hear subtle
differences.

Which of the the above reaons do you think are most likely?


If you ask me : the last one. Enough changed in audio since 1990 to
spur newer comparisons. (See my posting to Mr. Audio Guy). It is
expensive but not beyond the possibilities of such as Boston Audio
Socy. I saw the design of a Seattlee AUDIO Socy AbX test. Then
silence. No results. Was it your reason 3.? I don't know and I never ,
never speculate.

The irony of this statement must have escaped you. As far as I can
tell, your position *is* speculative, given that it is based on very
specific assumptions (see above).

Especially since the stock market expired. If it
works why don't people do it?

cut

A "test" which depends on statistics can not be used as a universally
recommended method of differentiation. It may be O.K. for some and
worse than useless for the others. And the devil is that no one can
tell if he is being deceived by it when he gets a null result because
he may perform differently in 6 months time or when not bothered by
ABX. Or not. Do it at your own risk. Like choosing a book to read, a
movie to attend or wine to drink. Nobody pesters you with a" test"
there. Sorry, "trends" are good for public opinion polls, not as
guidance for inndividuals.

Hearing perceptions are more similar from person to person than their
preferences in books or movies or taste in wine. If they weren't,
people wouldn't have been able to design audio codecs, which rely upon
universal characteristics of human hearing.

However, it is true that people have varying ability to hear certain
things, and that this variation affects their preferences.

There are two answers to the question "Which sounds best?" One answer
is the one each individual gives after personal audition. The other
answer is based on group results. Which answer one should choose is
based on the particular circumstance.

Darryl Miyaguchi