hi what's the best way to timestretch an audio source as it is made? it'll be from a synth to max/msp via firewire.

timestretching

obviously it will only be possible to timestretch retrospectively; that is immediately after recording. The simplest setup would make use of three key objects: [record~], [buffer~] and [groove~], the latter will allow you to playback the buffer contents at variable speeds. If you wish to decouple pitch and time (independent pitch and speed), then you're probably talking about granular playback, which is a little more involved, but eminently do-able with MSP. Just search the forum for "time stretching", "granulator" etc. And look inside the Cycling74/examples folder for the Max granulator; the grain engine in that patch is called "rgrano.maxpat" and you could plug that into your recording patch. And there's some old granulator tutorial vidz of mine here:

Hi
obviously it will only be possible to timestretch retrospectively; that is immediately after recording. The simplest setup would make use of three key objects: [record~], [buffer~] and [groove~], the latter will allow you to playback the buffer contents at variable speeds. If you wish to decouple pitch and time (independent pitch and speed), then you're probably talking about granular playback, which is a little more involved, but eminently do-able with MSP. Just search the forum for "time stretching", "granulator" etc. And look inside the Cycling74/examples folder for the Max granulator; the grain engine in that patch is called "rgrano.maxpat" and you could plug that into your recording patch. And there's some old granulator tutorial vidz of mine here:

And for more advanced live processing, search for J F Charles and spectral processing

and i could bang so that it jumps to and starts to stretch what i'm currently playing?

Yes, but not what you're "currently" playing, only what was recently played. Depending on the setup, you could timestretch as recently as maybe 200ms, but this isn't set in stone.