Here is the step on how to make sure that the sound mixer is set correctly for ARMA 3. It may be possible that accidentally, you have lowered the volume of ARMA 3 and hence there is no sound coming. They allow the user to change the individual sound levels from different applications as well instead of controlling the sound system-wide. Sound mixers are another important feature of Windows OS.

Sometimes the audio setting might be out of place which might be causing you to hear only partial sounds of the game.

You can also check the configuration of your sound in the Control Panel to ensure that the correct settings are in place. This has been working for a lot of players around the world. Try updating your audio driver however if the problem still persists, disable Windows Sonic for Headphones. If your game has no audio or has partial audio meaning that some sections of the game have audio while cutscenes or different elements do not have any audio, it means that your audio driver is misconfigured or is outdated.