General Sound Issues and System > Sound > Volume Mixer

I have had general audio stuttering issues when connecting Bluetooth headphones, especially when switching the default audio in-game, in Social > Audio > Voice Chat to Use System Communication Default.

I *must* set my Voice Chat Input Device and Voice Audio Input Device to a specific device for audio quality. System Communication Default does not work, and drops both headsets I've tried to extremely low quality audio. 

In Windows, while ensuring the Bluetooth Headphones were not set as System Default for Audio Input or Communication, and the external microphone is set as System Default for Communication (the only way sound in Marathon sounds better than Mono in headphones) I found: