Question re copying cassette tapes

[William J Poser]

Yes, an audio CD must be stereo, 44.1 KHz, 16 bit. But that's not the
question. If you're digitizing analogue tapes, the data is likely to
be used in a variety of ways, only one of which is making audio CDs.
When you want to make an audio CD, if your data is in another format,
you convert it to the audio CD format, which is easily done. If your
original recording is monaural, as most linguistic recordings are in my
experience, there's no point in wasting space and processing time in
digitizing it stereo (or even worse, as can happen, digitizing one
channel of voice and another of background noise). If you need a
"stereo" version for an audio CD, it is a trivial matter to duplicate
the single channel.

With regard to higher sampling rates, I agree that they're desirable
for music, which is of course what the recording industry is concerned
with, but I repeat that there is not the slightest evidence that anything
of significance in speech is found above 10Khz. Even if real psychophysical
experiments rather than anecdotes demonstrate that people can tell the
difference, the question is, does the difference matter? Piles of evidence
form psychophysical experimentation together with practical experience
in both phonetics research and speech technology indicate no.

If you've got lots of space and processor time go ahead and digitize at
44.1K, but for straight speech data there really isn't any good reason to go
so high. 

I concur that the quality of the digitizer can make a lot of difference
(as can setting the input gain properly so as to take advantage of the
full range of the quantizer while avoiding clipping.)

Bill