Re: IMHO, dat stat...


Subject: Re: IMHO, dat stat...
From: Eric Somers (somers@sunydutchess.edu)
Date: Thu Jul 29 1999 - 13:55:06 EDT


At 09:38 PM 7/28/99 -0500, you wrote:

> Thanks for the quick responses. The other thing I forgot to mention is
that I have
>a G3 Mac with RCA jacks, which I would like to be able to go in and out of
freely.
>What are digital outputs? Prongy things?

I don't think even the newest Macs come equipped out of the box for digital
audio input. You need at PCI card which has sp/dif or another digital
audio I/O standard (AES, Lightpipe, etc.) You can receive and send sound
in analog mode, but you won't gain the advantages of no generational loss
that you get with digital I/O. Also, most computers that handle analog
audio inside the box do not have a super good signal-to-noise ratio.

>Plus... isn't compression generally bad
>for sound, unless it can be uncompressed to its natural state? This stereo
box I have
>has compressed sound output - if there is a loud sound it grabs hold of it
really
>quickly and pulls it down, and it really destroys the natural space of
what's being
>played. I'm not sure if this is a different kind of compression than the
mini disc?

Do not confuse data compression with dynamic compression. Some DAT and
minidisc recorders do have a dynamic limiter designed to prevent distortion
from overly loud input. I would advise against turning these on except in
extreme situations. They tend to cause a "pumping" artifact that is
unpleasant and not natural. Recording studios and radio stations often have
to do some dynamic compression but they use very expensive equipment which
still retains good relative dynamic relationships while limiting extremes.
But these devices cost more than DAT recorders.

Data compression is used to get more information in less space. Some forms
of data compression, such as the PICT format for images on the Mac are
"lossless" -- that is, they do not discard any of the original information
and a complete image can be restored to exactly the state it was before
compression. Other schemes, such as JPEG for images, are "lossy" meaning
they throw away information that the user is unlikely to be able to
perceive in order to save space. The ATRAC scheme used in the Minidisc is
like this (as are MPEG audio layers 2 and 3). The least implementations on
the minidisc recorders are very good and the data loss is probably not
noticeable except for the highest quality recording applications (classical
music mastering for CD, for example). Many broadcasters use minidisc
successfully for documentaries, commercials, etc. Only fine concert
programs may require the higher ability of DAT.

But lets say you do spring for a DAT recorder. In order to take full
advantage of the higher quality of DAT you will need a very expensive
stereo microphone (at minimum). And since most portable DATs don't have
very good mic pre-amps you will need a high quality outboard mic pre. So
in addition to buying the DAT you will be spending $2000-$9000 US for mics
and a preamp to take advantage of its full quality.

If you want to record sounds in the field, samples for use in e-a music,
audio "notes," etc. using a lower priced stereo mic [Consider the Audio
Technica AT-822 or AT-825 (X=Y stereo mics with unbalanced (822) and
balanced (825) outputs -- about $260-$350 US or a slightly higher priced
model by Sennheiser] then you will hardly notice the difference between an
high end mini-disc portable and a low end (consumer Sony model) DAT. The
mini-disc will be less finicky and will use far less battery power. (My
Sony requires four AA batteries for every 2-hour tape recorded).

Both minidisc and DAT offer superior quality to the analog cassette, though
the analog cassette is the most "rugged" of the formats if you are
recording in very hostile environments (extreme heat or cold, humidity,
dusty air, etc.). My Sony Professional Walkman with Metal tape in heavy
ceramic cassettes (Denon tapes that cost $8 or more each), using Dolby C,
can still turn out a fine professional recording.

Though I have all three formats, I find that I tend to carry my minidisc
most often when traveling (because of its size and long battery life), use
my DAT only for classical music recitals (with fine mics and a small mixer)
and use by analog cassette where there is risk of damage to the recorder.
All can be used successfully with a little skill and care.

- Eric



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