lee suggested PD, i would suggest SuperCollider. i have written many supercollider patches to do this sort of thing, but these are all in Mac - i'm still getting to the point of compiling SC in linux in my "free time" (tm). (though closer now, with debian unstable +alsa running on an older ppc!) anyway, in either app: one continuously running loop that tests (say every 0.1 second) for an input volume threshold, which, if crossed, starts a timer and starts writing to a buffer. my SC versions write start and stop sample numbers into an array to be accessed later. second, a loop that tests if there any sample in the buffer, and plays back accordingly, at rate*2 or whatever, or fft i guess if you want to shift pitch and not rate. third a loop that plays the default sample if nothing else is playing.. hope that helps somewhat... -- _________________________________________________________________ Jonathan Segel -- MAGNETIC -- PO Box 460816 S.F. CA. 94146-0816 4014 Brookdale Ave. Oakland, CA 94619 jsegel(a)magneticmotorworks.com <-----> magsatellite(a)yahoo.com http://www.MagneticMotorworks.com tel (510) 534 7825 cell (510) 484 7415 fax (425) 955 4495