Tone Daemon
the destroyer of devices that duck audio when silent
When sinks are added or removed, checks against /etc/toned.conf to see if there is a match, if there is, plays a tone at a given frequency and volume
example /etc/toned.conf
[[tones]]
frequency= 20
volume= 20
[[tones.match]]
object.path = "alsa:pcm:0:hdmi:0,2:playback"