[Asterisk-Users] Echo cancellation

Richard Scobie r.scobie at clear.net.nz
Thu Nov 27 01:11:10 MST 2003


Peter Zeltins wrote:

> 
> I do not have a hardphone to play around with, but the echo is there both
> with built-in audio card (SigmaTel) and Bluetooth headset. There are no
> mixer settings than I can adjust as well. I'll try disabling AGC and/or
> lowering mike sensitivity.
> 
> Peter
> 

According to the excellent Cisco paper "Echo Analysis for Voice over 
IP", which the Wiki links to at:
 
http://www.cisco.com/en/US/tech/tk652/tk701/technologies_white_paper09186a00800d6b68.shtml 


"Headsets are particularly notorious for poor echo performance.". This 
is due to lack of acoustic isolation. Perhaps you could test using 
headphones and a mic.

After reading the above paper, I was able to tune my setup and make a 
significant improvement. Given the high number of questions about echo 
on the list, it would almost be worth including the link to it as a 
file, "README.echo" in the source.

Richard




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