Audio quality bad with some callers

[Pat3]

I get complains from users that the audio quality with some external calls are not good and that it is sometimes difficult to understand at all.
How can this be debugged?
Is there a possibility in 3CX to get the used codecs per call logged? For internal calls I have so far not received any complains.

We have configured the following codecs on the 3CX Server:
Codec Priority
G.711 A-law
G722
G729

and in the Client the following:
GSM
G.729
PCMU
PCMA
G.722

In the general Server settings we have the following codecs:
local/internal calls:
PCMA
G722
G729
OPUS
GSM
PCMU

Codec priority for external calls:
PCMA
G722
G729
GSM
PCMU
OPUS

• 3CX Version 16.0.2.910
• Server OS Windows Server 2019
• Is the 3CX Server Hosted and where? locally hosted
• IP Phone Make/Model/Firmware 3CXWin8Phone.exe 16.0.1.81
• Provisioning Method: Local
• Trunk Provider Peoplefone.ch
• Has the Firewall Checker passed: YES
• Are custom Phone Templates being used: NO

 

[eddv123]

to get the used codecs per call logged

Yes its call Wireshark
https://www.3cx.com/docs/capture-network-traffic/

If you run the trace from the PBX you can get both legs of the call (provider/phone) and look at the SDP body for the codecs. If the provider supports tracing on their platform this is a good things also.

In regards to the issue itself audio is this the provider:
https://www.3cx.com/docs/swiss-sip-trunk-peoplefone/

I would also if you can capture this bad audio check both legs and see if the bad audio occurs on the provider leg or local leg.

 

[JohnS_3CX]

Hi Pat,

I'm guessing that now incoming calls sound good, but outgoing calls sound bad in comparison. Probably the audio is being transcoded because the client initiates with GSM and the PBX accepts it, but then has to transcode before sending it out.

In the reverse direction, the call arrives as G.711 / PCMA and the client accepts it so it sounds better.

Try moving all the clients quality up to PCMA to match the rest of the setup, and reprovision them to take effect.