Reverb allpass and delay lengths

Algorithm development and general DSP issues

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donstavely
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Joined: Thu Jan 07, 2010 2:29 pm
Location: Windsor, Colorado

Reverb allpass and delay lengths

Post by donstavely »

I wish Kieth were here to answer this. Frank, please give it your best shot. Or if Sean is still listening, you might have the best insight based on your work in reverb and discussions with Kieth.

The question is, how does one come up with a good set of delay lengths for the allpasses and delays in a particular reverb loop? I have looked at the source for the various reverbs and reverb+effects that are on the site - over a dozen in all. I can't find any rhyme or reason to the numbers, besides that you want them to be somewhat random. Some have the delays get longer with different room size, some do not. Some are less than 700, some longer than 4000.

So what tools or techniques do you use to get good, even reverb density? Do you simulate or experimentally observe the impulse response? Are there any guidelines for where to start?

I understand the "it's an art not a science" aspect here. But it isn't totally trial and error, is it? The thread with Sean a while back was excellent, but it didn't address this aspect of the problem.

Thanks,
Don
Don Stavely
frank
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Post by frank »

This is one I can answer like Keith would have, he based it experience. He had been doing it for so long he knew what lengths made a good starting point for a particular type of reverb then he would adjust them by listening to make it sound like what he was looking for. He didn't use equations or formulas for this.
Frank Thomson
Experimental Noize
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