Sony STR-DA5200ES Operating Instructions Manual page 49

To activate the muting function
Press MUTING on the remote. To cancel,
press MUTING on the remote again or turn
MASTER VOLUME clockwise to raise the
volume. Even if you turn off the receiver, the
muting function works when you turn the
receiver on again.
To avoid damaging your
speakers
Before you turn off the receiver, be sure to turn
down the volume level.
49 GB