Has anyone heard of a loop effect that can be set to correspond to a bpm that can later be augmented live to a different bpm without changing the pitch? I've got a couple of songs with my band where I have a lick or chord structure that starts by itself and then has something else added on to it later. We don't have personal monitoring systems or anything though, and I feel that if I do a normal loop effect, the timing will be off with the drummer. I'm pretty sure this accomplishes the same thing that a synth can do with pre-recorded material (I've got a Yamaha midi keyboard that should be able to do it if the part can't be done just with me and the loop pedal), but I thought it would be a cool thing to do live (we don't have personal monitoring systems or anything). Feel free to point out my stupidity, I don't know much about what I'm talking about.
The boss rc20-xl can and i believe the digitech jamman can. the rc-2 cannot.