Would it be possible to add the ability to control the bpm with an an expression pedal? Being able to ramp up or slow down a song would be real neat.
I think you gonna pitch the song!
You could do that when the device is playing back MIDI data, like in the case of the Beat Buddy.
Audio Loopers though typically can’t do real-time audio stretching. I have 1 that has a varispeed function which works okay, but I never really found a lot of great uses for it. (it won’t do smooth BPM control)
I did make a MIDI master clock with the ability to control the BPM of other MIDI devices, plus it adds continuous control of the BPM. It’s fun to have the flexibility of that. If I ever get an audio looper that can actually do this in real-time, I’ll be all over it.