Asterisk g726 transcoding problem

Hello folks,

We have a problem with a clean install of Asterisk x64 , to which we are migrating from 1.4
We generally use Linksys SPA922 IP phones and are connected via SIP trunk to the outside world.

Our provider requires the use of g726-32 as the preferred codec with occasional use of g729 on specific lines.
On 1.4 everything was working flawlessly.

On 1.6.x we have experienced terrible quality in g726-32 sound quality whenever Asterisk is needed to transcode from other codecs. When peers talk or even transcode directly (i.e ulaw->g726) the sound quality is great, but whenever Asterisk moves in the sound is awful.

I’ve been trying to find a solution on the net to no avail and some similar bug reports are for older versions (or so I think).

So I’m quite stuck on this issue and can’t move on to alaw/ulaw because of ISP requirement.

Any ideas?

Thanks in advance!