Intermittent echo problem

[KilroyWasHere]

We are having intermittent echo. Our setup is as follows:
3CX v10 latest Service Pack running as a VM under Windows Server 2008 R2. 4gB RAM and 2 processor cores allocated to VM. The server is a Dell Poweredge 2900 with RAID 10 drives. The desktop phones are Cisco SPA525G2 with firmware 7-4-9c. Our SIP trunk provider is Broadvox. Our broadband connection is Time Warner Business Class Road Runner [10mb down and 1mb up]. Broadvox has been testing on their end but no problems have been found. The network switch is managed and set to prioritize SIP traffic. Same for the router. I dont know what else to do to find out what is causing this? I wonder if this problem could be caused by latency on our internet connection? If so, would switching to a T1 connection be the solution? Any ideas would be appreciated.

 

[leejor]

Which end is hearing echo? It is usually (but not necessarily) the result of too high of a level being sent to the far end, some audio "leaks" back (usually at the point it converts back from digital to audio) and because of the delay (in this case VoIP processing) you will hear the returning, lower level audio, as an echo.

Is it all calls/callers or just certain destinations/originators?

Have you tried a different make of set, perhaps the 3CX softphone?

 

[netswork]

We have this same issue with one customer. What is the best way to go about troubleshooting this? Is there a setting to modify the outgoing volume?