--- In Walter Knapp <>
wrote:
> If you are of the belief that ATRAC will not get what you want,
then you
> are into a high quality mic. ATRAC gets everything cheap mics
produce.
Yes, ATRAC (and MP3) works very well for human listening. However,
these systems benefit from the masking effects, that occur in our
ears. A soft signal will be masked by a louder signal, if it is
close in frequency (simultaneous masking). Also, a soft signal that
occurs before and after a louder signal will not be heard (temporal
masking). The ATRAC algorithm can therefore reduce the bit-depth for
such masked signals without any perceptible loss of fidelity.
However, even a cheap microphone would reproduce those signals, that
are ignored by ATRAC. So, if want to get the entire information
supplied by the microphone (not only the part, that is perceptible
to the human ear), compression as ATRAC or MP3 should not be used.
This is especially important if you want to analyze complex and
rapidly modulated sounds on a spectrogram display (or if the
properties of the human hearing system have to be examined).
> What you probably should do is record with what you have, and see
if the
> ugly effects record. If not, then go for something new. I'm not at
all
> convinced you will need all that exotic equipment to record these
sounds
> well enough. I do think it's probably going to come down to the
mic more
> than the recorder.
I agree. As far as I know, there is no evidence, that humans can
hear sounds above 20 kHz at all. The only argument for sample rates
higher than 48 kHz seems to be, that the cutoff-frequency of the
anti-aliasing filter would be not so close to the highest signal
frequencies (and the low-pass filter can be less steep). This could
prevent some potential distortions at these high frequencies. I have
the impression, that many manufacturers of consumer products use the
new 24/96 or 24/192 capabilities for marketing reasons only (large
numbers sell). I recently tested the new SoundBlaster Audigy 2
soundcard, that claims to be able to record at 24/96. It turned out,
that this card was unable to record any sounds at frequencies above
24 kHz. The 192 kHz playback mode was able to reproduce signals of
up to 80 kHz, but there was an incredible noise floor at these high
frequencies. I returned that useless card....
Raimund
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