Improvised performance using spatial modulation synthesis, which involves the high-speed (up to 760mph) simulation of moving sound sources. In this piece the sources include a triangle wave (purple), drum samples (orange), and scanned synthesis of the sound trajectory itself (blue). In every case, the visuals represent the trajectory path of the moving sound. Extreme indices of frequency modulation are achieved via physical simulation of Doppler shift, which goes to infinity at the speed of sound.