EMU_CHAN_IP
emu_wrptr(sc, ch, EMU_CHAN_IP, 0);
emu_wrptr(sc, v->vnum, EMU_CHAN_IP, initial_pitch);
emu_wrptr(sc, v->vnum, EMU_CHAN_IP, 0);
emu_wrptr(sc, v->vnum, EMU_CHAN_IP, initial_pitch);
emu_wrptr(sc, v->vnum, EMU_CHAN_IP, 0);
emu_wrptr(sc, ch, EMU_CHAN_IP, 0);