I'm not Arny, so you'd have to ask him aobut any ABX tests of teh various
formats, but I believe he would tell you that some have been done but not by
him and they came back as no difference for the people who participated.


"SD" wrote in message
...
On 3/22/2006 8:22 PM, wrote:
Things that I've found state that we don't need higher rates.

First, we have this thread from the JREF fourm on science, etc. with some
comments by one of the foremost experts on perceptual coding and thigs
digital, a fellow named Johnston:
http://forums.randi.org/showthread.p...=digital+audio

Of course this was written in 2004, so ther emay be newer info or
opinions from Mr. Johnston.
I see there is someone asking for an answer to this very question, so
perhaps there will be a more up to date answer soon.


Another example:
http://www.helsinki.fi/~ssyreeni/tex...s-over.en.html

Based on what is known about hearing, people do not truly hear anything
beyond 25kHz. And even this is quite a conservative estimate, since it
primarily holds for isolated young adolescents. And even if some people
do hear frequencies that high, the information extracted from the
ultrasonics is very limited-there is some evidence that everything above
some 16kHz is sensed purely based on whether it is there, irrespective of
the true spectral content. As for dynamic range, research suggests that
22 bit accuracy should cover the softest as well as the loudest of tones
over the entire audio bandwidth.

Perhaps the most straight forward reason why SACD is a bad idea is that
it is perhaps not needed at all. Blind listening tests tell the average
consumer has a fair bit of difficulty telling 24 bits at 96kHz from
properly implemented 16 bits at 44.1kHz. Considering the numerical
differences between these formats the question of whether we really need
accuracy beyond the level of CDs becomes quite acute. Quite some people
with golden ears agree that the difference is subtle. Now, the effective
bit depth of DSD is around 20 and 24/96 already has over an octave of
ultrasonic bandwidth. Why is it that by and far, the same golden ears
find a great difference between CDs and SACDs?

The favorite demonstration used to illustrate the extended frequency
range of SACD is to display what happens to a 10kHz square wave when it
is recorded on CD and SACD and then played back. The illustration
consists of four oscilloscope shots and displays how SACD produces a very
close approximation to the original square wave while the corresponding
result for CD is a considerably rounded waveform which is closer to a
sine wave than a square one. The pictures are very convincing and will
probably spook quite a number of CD owners. They are accompanied by a
brief description which tells how CD loses harmonics of the test wave
from the third up and so is clearly inferior to SACD. What is forgotten
is that the second harmonic of a 10kHz periodic waveform (which CD can
handle) is at 20kHz, already at the upper limit of hearing for
adolescents. The third harmonic would be at 30kHz and there is little
evidence that people are able to hear that high under any reasonable
conditions-it's ultrasound. So is the demonstration meant for you or for
your dog?

Similarly deceptive an illustration displays a scope shot with a cycle of
something resembling a sine wave and an approximate DSD bitstream below
it. It is easy to see the mean density of the bitstream closely
corresponds to the value of the sound wave at each point in time. The
text claims that since the stored bitstream is so close to the original
wave, the resulting playback quality is superior to the one offered by
PCM techniques. But what this really aims at is convincing those people
that have reservations toward digital audio media and prefer good ol'
analog. The fact is, the stored structure of the data doesn't matter a
single bit as long as the output voltages closely follow what went in.
After all, what is stored on a SACD displays little resemblance to the
pure DSD stream the data carries. What matters is the subsequent
processing and the soundness of theory behind it, as always.



Or this one: http://www.edn.com/article/CA276213.html

One claimed benefit of high-resolution audio that likely holds no water
is the belief that high sampling rates and consequent ultrasonic
frequencies aid in precisely locating a sound source. This phenomenon,
the Haas effect, refers to the fact that the phase-that is,
time-difference between when a sound hits one ear and when it hits the
other is one of two means by which you acoustically place its source in
3-D space. (The other means is the intensity difference you perceive
between one ear and the other.) The time difference between any two 44.1-
kHz samples is approximately 23 µsec, yet the human auditory system can
resolve phase- and time-delay differences of only a few microseconds
(defined in part by the distance between an average person's ears).



Arny,

Have you done any ABX tests comparing CD to SACD to DVD-A? The average
human can't hear sounds over 20Khz so I think the CD is perfect.
Production quality and recording quality are much more important. As we
move to hard disk music storage (for me FLAC) why would I want to increase
my storage space needs if it doesn't result in better sound?

SD

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