[net.audio] Noise reduction for CD's

wjm@lcuxc.UUCP (B. Mitchell) (12/04/84)

When taping a CD, you want to be able to record the 90dB
dynamic range that CD's can theoretically produce (I say theoretically because
most music recorded on the CD's doesn't take advantage of this).  Therefore,
if you want to tape a CD, you want the best NR system available and that's dbx.
A good tape deck with dbx NR can give you close to the 90dB dynamic range of
a CD, since dbx can provide up to 50dB of noise reduction.  The best Dolby C
can do is 20dB and Dolby B can only provide 10dB.
Regards,
Bill Mitchell ({ihnp4!}lcuxc!wjm)

don@oakhill.UUCP (Don Weiss) (12/07/84)

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Let me second your comments about dubbing CDs onto analog tape, and add some 
experience with dubbing onto digital tape as well.

The best way I have found to dub CDs is actually onto open reel, 1/4 inch,
half-track tape at 15 ips with DBX type 1.  With this setup I have not been
able to hear any noise buildup (even between tracks) or breathing (even with
low level frequency-limited percussive musical effects).

Said method actually provides better noise performance than dubbing to
digital VCR tape, using either a Technics SV-100 (EIAJ 14-bit) or Sony
PCM-701ES (using 16-bit format).  Of course, these methods have other 
advantages, such as tape cost, that make them the method of choice for me;
in fact if not for the cost, I'd probably do all my dubbing onto analog in
the manner mentioned above.

Shmootek!			Don Weiss

cliff@unmvax.UUCP (12/17/84)

> Let me second your comments about dubbing CDs onto analog tape, and add some 
> experience with dubbing onto digital tape as well.
> 
> The best way I have found to dub CDs is actually onto open reel, 1/4 inch,
> half-track tape at 15 ips with DBX type 1.
	...
> Said method actually provides better noise performance than dubbing to
> digital VCR tape, using either a Technics SV-100 (EIAJ 14-bit) or Sony
> PCM-701ES (using 16-bit format).  Of course, these methods have other 
> advantages, such as tape cost, that make them the method of choice for me;
> in fact if not for the cost, I'd probably do all my dubbing onto analog in
> the manner mentioned above.

Hmmm... I don't hear any noise when I dup CD's with my Nak DMP-100 (16-bit).
Maybe I am not listening well enough or the tweaking that Nak requires is worth
it (the Nak is a Sony that meets Nak's tolerance specs).  Any idea where the
noise comes from?  Were those CD's digitally mastered?

	--Cliff [Matthews]
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