[asterisk-users] LAN IAX2 trunk bad audio quality vs. LAN SIP trunk good audio quality

[Vieri]

Hi,

I have an audio quality problem regarding IAX2. I have 2 Asterisk servers interconnected via 2 LAN trunks at 1Gbps (no nat, no firewall).
One trunk is SIP and the other IAX2.
Normally, I use IAX2 but have noticed easily reproducible audio quality problems (voice in/out is OK but there's a "third" noise overlapping with a "scratchy sound" as if it were some kind of interference).

So lately I setup calls to go through the SIP trunk and audio quality is OK (no "third overlapping noise").

This is happening between Asterisk 1.4.31 and a 1.2.40.

I'm wondering if there's something I can tweak in IAX2 to eliminate this artifact.

Could the IAX2 jitter buffer between 1.2 and 1.4 be an issue (I believe it's enabled by default)?

Thanks,

Vieri