I understand - it not so important thing on this time of development dayz, but...
May be your team added option ingame settings like a "Radio" in sounds tab?
Becouse if use portable radio transmitter(walkie-talkie) - then recive so silent.
I play in headphones on maximal volume and when somebody try tolking with radio - so difficulty understand why he sayd.
I don't known why it problem: may be microphone settings other player so silent, may be something else.
I be so happy if you(devs) - give players this settings and i can make incoming voice in radio more loud.

Sorrry for my bad english and waste your time.
Have a nice day and good luck in development=)