I have been wondering about using audio/sndio and sndiod on FreeBSD. So, I found /usr/local/etc/rc.d/sndiod. From here, it should be enabled with
service sndiod onestart, and by entering sndiod_enable="YES" in /etc/rc.conf.local. When I didn't have a sound interface, the output from
mixerwould state so. sndiod hasn't been looked at much, and it would be cool to determine or to select it to be used to play sounds.