f(x) to fade applause

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Gauss256
Posts: 18
Joined: Sat May 21, 2005 2:35 pm

f(x) to fade applause

Post by Gauss256 » Sun Oct 21, 2007 7:46 pm

This is a solution I want to share, not a question. It might be useful for anyone who needs a long fade.

I bought Keith Jarrett's The Carnegie Hall Concert recently. Great album but the producers made the decision to leave in an insane amount of applause. E.g., 2.5 minutes after a six minute piece. I decided to use GoldWave to fix it. My first thought was to delete most of the applause and use Fade Out to taper off what was left. But that didn't sound great. I wanted a fade with a longer tail.

So I implemented an expression (given below) which provides an exponential decay. The results sound much better. Some of the numbers are hard-coded to give:
* 5 seconds of applause at full volume
* 10 second exponential fade
* zero out anything beyond that

You set the selection at the beginning of the applause and run the expression evaluator. Afterward I run AutoTrim to trim all but two seconds of the resulting silence at the end.

It took a bit of fiddling to get this working right, so I thought I would share, just in case anyone else has a need for a long fade. The expression is

wave(n) * (1 + limit(2 * (exp(-x * sgn(t/10 - 0.5) * (t/10 - 0.5)^2) - exp(-x)) - 1))/2

with x=4, Initial t=0

Bruce

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