Sennheiser EM 3731-II User Manual

Additional information

HiDyn plus™ (HDP) noise reduction

This product family is equipped with

HDP

, the Sennheiser noise reduction

system that reduces RF interference. It increases the signal-to-noise ratio
in wireless audio transmission to more than 110 dB.

HDP

is a wideband

compander system which compresses the audio signal in the transmitter
in a 2:1 ratio (related to dB) to lift it above the inherent noise floor of the
RF link. In the receiver the signal is expanded in an identical and opposite
way in a 1:2 ratio to restore the original signal, at the same time reducing
the RF noise to below the noise floor of the receiver.

HDP

has been specially developed for high quality radio microphone

systems.

All receivers of the product family feature a AES3 digital audio output for
digital mixing consoles. In the receiver the audio signal is digitalized as
early as possible so that the noise reduction (compander) can be realized
digitally.

Squelch

Depending on the strength of the received RF signal, the receiver’s audio
output is opened or muted. Via the “

Squelch

” menu, the squelch threshold

can be adjusted in 13 steps from 0 to 30 μV.

RF link

Transmitter

Receiver

Inherent

noise

of the RF link

Only transmitters and receivers that are equipped with

HDP

can

work correctly with each other. If non

HDP

equipment was mixed

with

HDP

, the dynamic range would be drastically reduced and the

transmission would sound blunt and flat.

HDP

is permanently

active and cannot be switched off.