Sound quality issues

[RuntyCardinal]

Good morning,

Two of my users are having sound issues, and I have been unable to track down the cause. While on a call there is some static and the call volume will vary during the call. Some times it will sound like the caller is yelling or whispering into their phone.

I have contacted the trunk provider and they were unable to find an issue on their end. I have also tried: swapping headsets, swapping phone bases, using PBX delivers audio, and re-provisioning. Please advise if there is anything I can try to resolve this issue.

Thanks!

 

[AWS2P]

Hi Runty,
Please start here :
https://www.3cx.com/community/threads/information-to-provide-when-requesting-help.67558/

 

[eddv123]

Is this easily replicated ? or "intermittent" ? if you can replicate easily I would first run a PCAP capture and check the call streams, you can see in Wireshark if there is anything obvious: https://www.3cx.com/docs/capture-network-traffic/

 

[Alphabetic]

Are these EXT using STUN by any chance? If so, have you defined local SIP ports and port forwarded RTP/SIP ports to the respected phones?

 

[RuntyCardinal]

3cx version 16 Pro
Server OS is Windows 10 Pro
Server is hosted in house
Phones with issues: Htek UC923
Provisioning Method: Local Lan
Trunk: ATT
Firewall checker passes all but SIP ALG
Default templates in use

I'll try and run the wireshark capture a little later today. Thanks

 

[AWS2P]

So first , search how to remove SIP ALG, sip alg feature can produce unpredictible behaviour with PBX.

which audio codec is expected by ATT? is this codec set in first place in your trunk settings.?
Do you have same codec order used in extensions to avoid transcoding

 

[eddv123]

Firewall checker passes all but SIP ALG

I don't think it is the root cause of your current issue but regardless SIP ALG requires disabling as it will cause issue with malforming your SIP headers = dropped calls etc.

 

[Alphabetic]

Do you have audio issues when dialling EXT to EXT?

is it for incoming and outgoing via the trunk?

is it every call?

Does the poor quality show in call recordings?

 

[RuntyCardinal]

For the SIP ALG, it passed the test prior to upgrading to V16. We have double check the firewall rules and are unsure of why it is failing now.

The audio issues are on all calls. EXT to EXT, outbound and inbound. I haven't tried a call recording I'll see if I can do that later today as well as the packet capture.

 

[Alphabetic]

And its only for these 2 EXT?

are the other EXT on the LAN with the same set up? same phone? same power supply? same network toplogy?

Are you able to get them to do echo tests from their phones by dialling *777 - hows that?

 

[RuntyCardinal]

All phones are powered by a Cisco SG300-28PP. During the Echo test there are a popping noise, but not a static sound. We do have a mix of phones we use Htec UC923 for 11 users and Yealinks for 4 users.
I have found 3 recording that have the static sounds recorded, and I created a capture of the last call that has static in it as well. Unfortunately, I'm not sure what I'm looking for in the Wireshark png.