let off0 = abuf.get_offset(self.channel);
let off1 = abuf.get_offset(self.channel + 1);
self.ics[0].synth_channel(dsp, &mut output[off0..], srate_idx);
let off0 = abuf.get_offset(self.channel);
let off1 = abuf.get_offset(self.channel + 1);
self.ics[0].synth_channel(dsp, &mut output[off0..], srate_idx);