[asterisk-users] Voice quality issues

[Alan Chandler]

Being new to Asterisk, I have set up a little test rig at home.

Asterisk itself is the Debian Etch package, running on a Celeron 1.7G 
machine

I have two clients on a 100Mb LAN, a Windows XP machine with an Athlon 
XP2200+ processor, and a Linux Core Duo 6300 machine.

On the windows XP machine I run idefisk.  On the linux machine I can run 
either idefisk or kiax.  Both of these are obviously IAX clients.

When I connect the two of them together, I am getting quite severe sound 
quality problems in the direction of the linux to windows machine.  The 
best I can describe it is the sound coming out the windows machine 
sounds like a Darlek (very tinny sound with high pitched echo sounds).  
I think it represents an over compression problem.

The sound coming the other way (windows to linux) is fine.

I was worried about my raw capture capability on linux, so I just tried 
to record and playback directly on the local machine - but the quality 
here is good.

It also appears that the main media stream is not going through the 
Asterisk server as I have an iptables firewall that is counting iax 
packets hitting the machine and it is small (in the few tens).

How can I debug whats wrong here so I can try and correct it.
-- 
Alan Chandler
http://www.chandlerfamily.org.uk