[sdiy] digital delay, was ...

[harrybissell]

This idea has some of the merits of using the old oberheim
case to plant geraniums :^P

(otoh I don't think the sections of the same BBD would track well
enough to get any noise reduction in this manner...)

One twilight zone idea of mine would be to separate the audio into
several different bands (low mid high) and set the gains so that each
BBD wouls see maximum signal (the highs presumably would be
lower amplitude than the lows)... then when summing them back together
you would account for the different gains to get a delayed signal with
higher signal amplitude (better S/N)

twilight zone enough ???   :^P

H^) harry

Glen wrote:

> At 11:43 PM 9/11/03 , phillip m gallo wrote:
>
> >It was also a common hack to wrap a NE572 around either the Phlanger and the
> >RS "Reverb" to bring the noise issue into the realm of the useable.
>
> Here's a bizarre suggestion:
>
> Place several delays in parallel, to reap the noise reduction benefits of
> using multiple channels, as we discussed in a recent thread. When you get
> tired of doubling the number of units to get another 3dB of S/N, then
> things get really unusual.  :)
>
> All these delays will be built with dual-section chips, such as the
> SAD1024. The desired signal only flows through one half of the chip. The
> other half of the chip is used as an "empty" second channel. In other
> words, make a stereo delay unit, but only use one channel for your signal.
> Using dual chips keeps the two channels fairly well matched to each other
> in frequency response, noise level, etc.
>
> What about the other channel? You let a computer analyze the noise coming
> out of the "unused" channel, and then subtract the spectra of that signal
> from the channel with the desired signal.
>
> That's right, I'm suggesting to use a high quality ADC, a fast computer,
> and a high quality DAC to digitally process and remove the noise from the BBD.
>
> I told you it was a bizarre idea.
>
> I guess my mind has been wandering a bit, trying to think of something
> original to use my BBD chips for. I guess this idea might be original, but
> now I need to think of something that would be both original and useful at
> the same time.  :)
>
> I also just realized that this bizarre suggestion gets us back into the
> territory of a digital delay (by way of the Twilight Zone).   :)
>
> later,
> Glen Berry