chn_setmute_multi
int chn_setmute_multi(struct pcm_channel *c, int vc, int mute);
chn_setmute_multi(ch, SND_VOL_C_PCM, (*(int *)arg & SOUND_MASK_RECLEV) != 0);
chn_setmute_multi(ch, SND_VOL_C_PCM, (*(int *)arg & SOUND_MASK_PCM) != 0);