What is the best way to write scores for multi-instrumental improv jamming?

I'm mostly concerned with leaving enough clues to avoid or suggesting what to play to maintain a nice harmonic performance.

Thanks!

Last edited by Abdol; 10/23/19 09:18 AM.

Kawai MP7SE, Yamaha MOTF XF6, Yamaha WX5, Yamaha Pacifica 112v