AudioOutputUnitStop(powd->audio_unit);
AudioUnitUninitialize(powd->audio_unit);
CloseComponent(powd->audio_unit);
btr_remove_node(&powd->callback_btrn);
AudioOutputUnitStop(powd->audio_unit);
AudioUnitUninitialize(powd->audio_unit);
CloseComponent(powd->audio_unit);
btr_remove_node(&powd->callback_btrn);