RSS M-380 Owner's Manual page 183

If the relationship of -Inf dB < -20 dB < 0 dB < 10 dB is not
maintained, the setting will be ignored when you press [F8
(SET)].
8.
Press [F8 (CLOSE)].
The FADER CALIBRATION popup will close.
9.
Turn off the power.
Other settings and functions
183