I haven't gotten to that stage yet, but I just on the basis of the music experiments I've done, I heartily recommend Audition. I've used both the included CD of .cel sound files (a customized .mp3 file format; it lacks the fade-in and out, so you get razor sharp start-stop play action), and .wav files from the Magix Soundpool DVD's (worth every cent, and low cost to boot), and been able to extend and shorten play times without any noticeable change in frequency. I would assume that the controls that allow changing the frequency baseline would be just as precise. Never mind the fact that you can import an animation onto one of the channels and time your sound effects in Audition....