I checked in the issues report section and i didn't see anybody reporting this problem. I already reported it with other problems but you said i have to open a new one for each different one.
My connection is not the best ( http://www.speedtest.net/my-result/4090456396 ) but in other games that use the proximity chat anyone can hear me fine without lag.
In dayz basically no one can understand what i'm saying, and that ends with the guy i'm talking that shot me in the face. People can hear me talking but the voice caputre only frames of what i'm saying making it incomprehensible.
Especially in a role playing server it's so frustrating...