Major Voice Quality issues on 3CX Hosted w/ SBC

[U-A]

Have a client(actually 2, just other not as much) that has major popping sounds while making calls. We have gigabit Verizon high bandwidth connection and anyways its in a small(Dentist) office with very low internet usage. I'm using SBC which never seemed to be an issue. Speakerphone not super bad, handset is terrible(I thought the doctor was dreaming but he was absolutely right). I tried many test numbers but they all were popping making it super annoying to speak to anyone on a call.

Here are some of the things I have tried:

-Swapping routers
-Shielded/Grounded cables
-Swapping phones(Yealinks T57W/T58W)
-Swapping codecs..tried all including OPUS even tried high kbps not supported by 3CX template
-Put phone on WIFI
-Ferrite beads
-Local POE injector(not using POE switch)
-Ran 3 different fresh cables through the ceiling
-Put the SBC on dedicated computer
-Tinfoil hat
-(STUN - Didnt work at all)

Anything else I can try?

I literally have the same set up here as I have at many other clients with no complaints...

What am I missing?

Thank you!

 

[SweetAction]

If you record the call, popping noises in the recording? Indicates the popping isn't client specific (as recording happens PBX side)
Inter-pbx (1 ext to another ext) calls pop also? (isolate the SIP trunk from the equation)
Softphone (webclient/mobile apps) ok? (rule out routing through the SBC)

Could be a SIP Trunk issue.

 

[U-A]

If you record the call, popping noises in the recording? Indicates the popping isn't client specific (as recording happens PBX side)
Inter-pbx (1 ext to another ext) calls pop also? (isolate the SIP trunk from the equation)
Softphone (webclient/mobile apps) ok? (rule out routing through the SBC)

Could be a SIP Trunk issue.

Will try all those suggestions. Thank you!

 

[U-A]

Will try all those suggestions. Thank you!

Just tried all suggestions - inter office is just fine. Called from app and was horrible as well. I don't know why I didn't think of that...Obviously a SIP trunk issue..Ill need to take a closer look at that.

 

[SweetAction]

Just tried all suggestions - inter office is just fine. Called from app and was horrible as well. I don't know why I didn't think of that...Obviously a SIP trunk issue..Ill need to take a closer look at that.

And the recording shows/has the popping in it as well?