[Asterisk-Users] Echo cancellation

[Jason A. Pattie]

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Nicolas Gudino wrote:
| If the terminating tail circuit has cancelable echos and if the echo
| canceler is enabled, you will hear echo for the first few utterances and
| then it will die away. After a few seconds of speech, the echo should be
| gone or at least very quiet compared to the echo level at the beginning of
| the call. This is the signature of a working echo canceler. "

In my situation where we use VoIP softphones connecting to an X101P card
to the PSTN, the other end hears us just fine and there is no echo.
However, there is substantial echo on the VoIP clients.  I did one
extended test with X-Lite (or maybe it was DIAX, but I have the feeling
the performance would have been the same) where I was in an extended
conversation.  Echo was quite bad for the first portion of the call, but
after approximately 1 - 2 minutes, it progressively got better until
after that time, it was still there, but at a very controlled, curtailed
level.  The beginning and end of the echoed portions were chopped off
and the volume level of the echo was quite a bit lower than the audio
level of the two parties, to the point that it was no longer distracting
for the VoIP client to talk.  This was using the MARK2 with AGGRESSIVE
enabled suppressor.

|>"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.

What does this mean?  That the earphones are feeding back into the
wrap-around mic?  I have a USB Plantronics DSP 400 headset running under
ALSA sound system.  Is it feeding through the plastic parts and entering
the microphone sitting out near my mouth?

- --
Jason A. Pattie
pattieja at xperienceinc.com
Xperience, Inc. (http://www.xperienceinc.com)
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