Ive noticed that if your default recording or playback device selected in windows is incorrect when you launch DayZ (ie Default recording device is set on Stereo Mix instead of your microphone) you are unable to change it in DayZ or in Windows without restarting DayZ completely before the alteration in settings takes place.
Example: By mistake you launch DayZ with your default recording device set to Stereo Mix and while in game you realize it. You minimize the game and change your default recording device to Microphone in windows and return to DayZ and your default recording device is still Stereo Mix in game. You must restart DayZ as there aren't options concerning default input within the game itself.

The same thing happens if your Default Output device is changed while in game.

Can we get some default input/output device settings up in DayZ?