To preface this. Using 32-bit Arma 3. My Microphone works and I'm able to use it normally. I can see in Windows Privacy & Security that my Microphone is being accessed by Arma 3.
This isn't the case when I use 64-Bit Arma 3. I can see a Windows Host Process using my Microphone. But trying to use it in Arma 3. Nothing happens. I test it on different servers that have Voice Comms enabled, in the correct channels to do so but nothing happens. Additionally the Character doesn't make any mouth movements like what is usually supposed to occur.

I've use USB Headsets. And a 3.5mm headset. Both change nothing.
Said audio devices work with Steam and Teamspeak and everywhere else I've tried.