

	With relays alone, you will always get a transient when
you abruptly turn ON or OFF any channel.  If you don't want to hear
the transient, use some other device (a photoresistor-output optoisolator
is the usual sort of thing) to gently MUTE the signal, then switch,
THEN remove the power from the lamp in the optoisolator.

	It used to be standard practice to employ photoresistors
in switching audio, because the photoresistor time delay (a few
thousandths of a second) kept any noise in the digital side (which
drives the lamp) from contaminating the audio.  And, the devices
are cheaper than relays.