Sennheiser S1 NOISEGARD, User Manual

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Valuable information on NoiseGard
TM
/digital
S1 DIGITAL | 25
Valuable information on
NoiseGard
TM
/digital
Combination of two NoiseGard strategies
Active noise compensation (ANR, NoiseGard) is based on the principle of
cancelling out unwanted sound using “anti-sound” (phase-inverted
sound). Basically, one must distinguish between two different strategies:
the feedback strategy (FB) and the feedforward strategy (FF).
Operating principle of the two ANR strategies
Feedback ANR uses microphones integrated into the inside of the ear cups
to pick up the sound signal near the ear. This sound signal is processed by
an FB control circuit which then calculates the required “anti-sound” and
outputs it via the loudspeaker. This is the “classic” NoiseGard strategy
used in most headsets with analog NoiseGard technology. FB-NoiseGard
works especially well in the low-frequency range.
Feedforward ANR , on the other hand, uses microphones mounted on the
outside of the ear cups to directly pick up the unwanted noise. The FF con-
trol circuit then calculates the required “anti-sound” and outputs it via the
loudspeaker. Since the FF control circuit cannot become unstable at higher
frequencies, it allows for a strikingly increased NoiseGard performance in
the upper frequency range.
NoiseGard
TM
/digital uses both ANR strategies. Apart from the loudspeaker,
each ear cup features its own inner and outer microphone, allowing to
combine the advantages of both strategies. As a result, the NoiseGard per-
formance is outstanding both in terms of the amount of noise attenuation
and the frequency ranges treated.
The NoiseGard
TM
/digital technology of the S1 DIGITAL uses an innovative
approach. By means of the microphones, the current sound situation is
analyzed to fully calculate the optimum control circuit settings. This calcu-
FF FB
Adaptation
ou
ts
ide
no
ise
inside noise
anti noise
Engine