Sounding like a space cadet or robot on 3CX intercom calls between soft phones and desk phones

[gtaylorstc]

Post the update to 16.0.1078, we are having calls between soft phones and our office that sound quality is bad. Like space cadet or robotic voice quality. We have also seen this issue in soft phone to soft phone using iPhone XR and 3cx software 16.1.6 on the phones. Not every call, but likely about 25%.

 

[JohnS_3CX]

You should monitor the dashboard for CPU/RAM usage when the issue occurs.

Where is the machine hosted?
How many extensions?
What are the machine specs?
Do you have the same issue outside of softphones? (ie Deskphone to deskphone)

 

[gtaylorstc]

You should monitor the dashboard for CPU/RAM usage when the issue occurs.

Where is the machine hosted? It is on a linux box running KVM with multiple PBX instances located in a DC.
How many extensions? 8 extensions at most 3 active at any time with two of them in intercom calls
What are the machine specs? VM has 4GB of ram. I don't know the processor speed.
Do you have the same issue outside of softphones? (ie Deskphone to deskphone) Have not tested deskphone to deskphone.

 

[JohnS_3CX]

The first thing I would suspect (and don't take this lightly please) is lack of resources.

Lack of resources can degrade audio like your description.

1) CPU: Often multiple VMs may share resources on the same server (shared cores VS dedicated cores), and one machine can "steal" resources from another.

2) Network access: if the network access has issues due to the virtual NIC or the actual NIC on the host, you will have choppy audio as the very least of your issues, or robotic voice. Bandwidth starvation and lack of QoS can also make matters worse.



So these above would be a very good starting point to start investigating. Think of ways to test against your existing server (ie. by moving a problematic VM to an idle server or a dedicated machine and compare performance)

 

[Sobiera]

What kind of Deskphone do you use?
Have you checked the codecs?
Try PBX delivers audio on the extension and on the sip trunk.
Do you lose sip packeges?