> how do I create and apply an envelope that will cause a sound > of any length to ramp up in a fixed amount of time - say, .05 sec > - at the beginning and ramp down in a fixed amount of time at > the end? Since the x axis is arbitrary, the simplest way is probably to use the duration of the sound as the x extent: (let ((dur (/ (frames) (srate)))) (env-sound (list 0 0 0.05 1 (- dur .05) 1 dur 0)))