Sennheiser evolution wireless G4 500 P Series Instruction Manual page 60

CAUTION
Risk of hearing and material damage
If you set the squelch threshold to a very low value, a very loud hissing
noise can occur in the receiver. This hissing noise can be loud enough to
cause hearing damage or overload your system's loudspeakers.
▷ Before adjusting the squelch threshold, set the volume of the audio out-
put to the minimum.
Never change the squelch threshold during a live transmission.
▷
Using the EK 500 G4
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