[asterisk-users] Background Noise Elimination

[Matt Riddell]

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Norman Franke wrote:
> Greetings!
> 
> We have a somewhat noisy background in our call center, and I'd like to
> reduce this. Obviously, we could plaster the walls with sound absorbing
> material, but is there anything we can do in software either using any
> algorithms for our open source-based SIP library or inside Asterisk
> itself? Related to this, anyone have a good source for good panels?
> 
> We are using Plantronics noise canceling headsets, which don't really
> seem to work all that well. Our ancient system handled noise much
> better, but I suspect that was partly due to the Dialogic ADPCM
> algorithm used that just reduced the intelligibility of lower volume
> noises in general. We are using PCMU direct from the agent's mic to
> through Asterisk to PRIs, so we don't "suffer" from compression
> artifacts. The down side, is that you can make out even very quiet
> conversations in the background (like 3 agents to one side.)
> 
> How have people handled this? I'm experimenting with a noise gate that
> will lower the volume when the agent isn't talking, but that won't help
> when the agent is talking.

Nah, there's nothing really.

The noise gate is your best bet.  I would assume that while an agent is
talking the customer will be listening to the agent, so the background
noise will hardly be noticeable.

The issue is, while two people are talking its pretty hard to remove
just one of them from a wave file.

Try the noise gate and see how you go.

Oh, you might want to try a downwards expander instead (a noise gate but
with ratio as well as threshold).

- --
Kind Regards,

Matt Riddell
Director
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