Technical Description of TANDBERG 8000 with software version E3/B8
D12008 Rev. 11
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This setting is without memory (i.e. the system does not have to readapt when the movement
setting is changed).
4.5.5
Noise Reduction (NR)
Two sorts of noise can be removed when using the TANDBERG 8000, namely low frequency
noise and constant noise. The noise reduction algorithms are either both enabled or both
disabled.
The constant noise reduction algorithm available on the TANDBERG 8000 is able to reduce
noise with a slowly varying level and frequency response, i.e. the reduction is based on an
assumption that the noise is constant over time. Therefore, it will reduce noise from fans, air-
conditioning and PCs, but it will not remove conversation and noise caused by slamming doors,
coughing etc.
In case of very high noise levels, the constant noise reduction algorithm may introduce some
audio distortion. If distortion is a problem, verify that the microphone input gain is set properly.
Too low gain may cause distortion. If gain is set incorrectly, move the microphones closer to the
person speaking and adjust the input gain properly.
4.5.6
Audio levelling/ Automatic Gain Control (AGC)
The TANDBERG 8000’s Automatic audio levelling feature will ensure that the transmitted
audio will always be at the same level.
•
There are four independently selectable audio leveller/AGCs in the system; one common for
Mic 1, 2 and 3 and Audio in 4, one for Audio in 5, one for Audio in 6 and one for audio from
the remote side.
•
When enabled, the audio levellers try to keep the signal from the corresponding input at a
constant, fixed level, by attenuating very strong signals and amplifying weak to medium
signals. Very weak signals, i.e. normal background noise alone, will not be amplified. In very
noisy environments, the audio levelling should be turned off for best performance.
•
The main purpose of the leveller is to automatically adjust the signals to ensure that each sub
signal in a mix of different sub signals has comparable levels.
•
The leveller will also compensate for different speaker levels and different distances from the
person speaking to the microphone.
•
To ensure correct behavior of the leveller it is crucial that the input gain settings are adjusted
correctly using the ‘Audio Input level setting’ menu. The leveller will not compensate for
severe maladjustments of the input gain settings.
•
If using the Audio Bridging feature and calls to mobile phones or analogue phone systems
result in low audio, try setting the ‘Received Audio’ AGC to
ON
.
