Axis 241Q User Manual page 27

Noise cancelling is a way of reducing the background noise when there is no useful audio
present. A typical application could be when there is a noisy environment and you are only
interested in hearing the sound when someone is speaking close to a microphone. There are
two adjustable parameters available to optimize this function:
• Noise canceller threshold value
• Noise canceller attenuation
When the incoming sound is louder than the threshold, it will pass without any changes.
When lower than the threshold, the incoming sound will be reduced by a certain
attenuation factor. The threshold value should be set higher than the background noise,
but lower than the useful audio.
The noise canceller threshold value can be set to High, Medium High, Medium low and
Low. A lower threshold will accept most of the audio to pass. Only the weakest background
noise will be reduced. A higher threshold will make the noise canceller act on even
stronger background noise. At the maximum level High, there is a risk of reducing useful
audio as well.
There is a trade-off between noise cancelling and sound quality. In other words, increasing
the noise canceller attenuation deteriorates sound quality. Adjust the threshold and the
attenuation to an optimum by listening and changing the levels.
Axis video server - Audio (AXIS 241QA/SA & AXIS 243SA only)
27