The pioneer 4100nex works great in my Mazda 6 except for the phone calls. I hear them perfectly but the other person hears their own echo and its very frustrating to have a conversation when they don't want to talk. I tried placing the microphone everywhere in the car, changing out the microphone with another, turning down the mic sensitivity, turning down the Bluetooth volume before syncing the phone and using another phone. PLEASE if anyone have any other input, I would appreciate it. Thank you.

didi u ever get this resolved , i just started having this same problem on my 8100 

I've got the 7100 NEX, 2014 Mazda 6 with Bose....callers hear echos of their voice.   Have tried everything...volume levels, different mic, different mic locations, steering wheel adapters, etc etc.    Still have callers complaining about the echo.    This is the most expensive HU we have in our 3 cars and the only one that has this problem....    Any ideas?

When I first had my 8000 installed my mic was up by my sun visor, changing the volume levels didn't work either, caller still heard an echo, so I moved my mic and put it down by my speedometer. My callers do not complain about an echo anymore and I have their incoming voice level at a very comfortable level. My suggestion is to test areas to place your mic, adjust the voice volume, figure out which speaker the voice call is coming from.