EMU_CHAN_LFOVAL1
emu_wrptr(sc, ch, EMU_CHAN_LFOVAL1, 0);
emu_wrptr(sc, v->vnum, EMU_CHAN_LFOVAL1, 0x8000);
emu_wrptr(sc, v->vnum, EMU_CHAN_LFOVAL1, 0x8000);
emu_wrptr(sc, ch, EMU_CHAN_LFOVAL1, 0);