Question about audio when transferring to IVR

[Andy Oberlin]

I am having audio issues with a hosted PBX I installed. I am pretty sure I narrowed it down to be the remote site and their internet connection. But I don't want to assume anything at this point.

Right now the remote site uses a Raspberry PI SBC and they are experiencing sporadic audio issues which I can duplicate if I run Netflix or almost any streaming from their location. But what just threw me for a loop is they sent me a voicemail recording that was really choppy. I created an IVR that automatically dumps to someones voicemail and that IVR was used to transfer this call to the voicemail.

Here is my question when someone calls and it is picked up by an extension that is behind a SBC and then that extension transfers the call to a IVR that dumps to a persons voicemail box. Is it still going through the SBC at the remote location and is that where I picked up the bad audio?

I have a SIP firewall and that call got rated 4.41 MOS so I don't think that was the issue.

Any help is appreciated,

 

[Andy Oberlin]

Bump

 

[YiannisH_3CX]

Hello @Andy Oberlin

I cannot think of a scenario that would force audio through the SBC while the call is going through an IVR to voicemail.
I could be that the choppy Voicemail audio is a different issue that has to do with the server specs for example and not the SBC.
Can you replicate the choppy audio in voicemail? Does it happen often?

 

[Andy Oberlin]

Thank you for the reply.

No this would be the first choppy voicemail that I have heard. When I call externally to the system it always sounds clear. To rule out it being the PBX I actually moved it from my Hyper-V pool to a dedicated VMWare box and it has a ton of resources dedicated to it. When this choppiness happened I was monitoring their latency from our data center to them and it jumped up around that time to 200 and 300ms for a while off and on. And I received complaints from some users there that they were having voice quality issues. So that pointed me back to their location. Is there a chance the audio is still going through the phone that transferred it?

 

[YiannisH_3CX]

I cannot think of any scenario that would involve the phone to the audio stream. Since the call was transferred to an IVR and then to voicemail the phone should not be involved at all.

 

[TBWD]

I have had similar problems with choppy voice calls, we found that most were caused be the ISP having issues at the time (Level3). Even major data centers will experience high latency from time to time. If this is an ongoing problem I would advise moving to a more stable environment.