[sdiy] digital delay, was ...

[Harry Bissell Jr]

--- Glen <mclilith at charter.net> wrote:

> I realize that it wouldn't be a perfect match, and
> the potential noise
> reduction would suffer *at least* some. However, I
> have experimented with
> analyzing an "unused" channel of an otherwise
> "stereo" digital recording to
> remove the residual hiss caused by my soundcard's
> electronics, from the
> channel that actually carried my desired signal. 
> 
> It actually did work fairly well, at least in that
> case. It certainly beat
> trying to use tone controls, or using a dynamically
> adjusted low-pass
> filter in a single-ended noise reduction scheme ala
> National
> Semiconductor's approach. It was also better than
> the pumping of a
> compander approach.

I'd think the soundcard would work much better,
because
you presume that any artifacts of the computer itself
(backplane noise etc) would be injected into both
channels in a more or less equal manner.  With the BBD
you can only hope to remove some clock noise, not the
usual "hiss" (uncorrelated noise)... which would not
be
equal in both channels.  If the his had similar
frequency components and the noise reduction affected
that range of frequency, it might help a little 

H^) harry