When talking to an outside/external callers (via our SIP Provider Broadvox) they all hear their voice echo but we don't on our end (from the soft phone). We are running the latest 3CX Phone System v8 build along with the latest 3CX Assistant (8.0.11114) and Softphone (4.0.11015). We are all using logitec headsets with the softphone. We opened a ticket with Broadvox and they could not reproduce the problem. After further testing I found that if i mute the mic on the logitec headset, the external caller does not hear the echo. This intially lead me to believe the mic on the headset was picking up the callers voice from the headset earphone. So, I went in to Windows/Control Panel/Sounds and adjusted the mic sensitivity. I also lowered the volume on the headset earphones. However, the only way we can get the echo to go away is to actually mute the mic. Has anybody else experienced this? We also hear a faint echo when calling each other internally between extensions. But for now, we are most concerned with the sound quality for our external callers.