IOS Voice Gateway MOH Quality Issue

[mcvisser]

Hi,

I installed some toll-bypass (no Call Manager) 2651XM routers running G729B codecs. (E1 trunks into Siemens PBX). The customer now has a bit of a call-centre happening with the PBXs. When the operators lines are full they putting people on hold. The result is MOH generated at the PBX being hairpinned ( I think) over the VoIP circuit.

The issue is the Music-On_Hold is very poor quality. I have played with music-threshold and turned VAD off but it stills sounds bad. I assume the main prob is the G729B is not meant for music but voice. I have a bit of bandwidth to play with so my question is what codec should I choose as the best compromise. Is there something else I should (compressing the audio, equalising the audio ????)

[jasyoung]

Most music sounds absolutely horrible under the g.729 codec. Classical music tends to suck the least, if you need to stick with g.729. If you can afford the increased bandwidth consumption, the g.711 codec will deliver toll-quality voice. You could also try g.726, but I doubt it will be much improved over g.729. Here is some information on different codecs you can use and the tradeoffs involved:

http://www.cisco.com/en/US/tech/tk652/tk698/technologies_tech_note09186a0080094ae2.shtml