I found the decision, here:
Disabling Hands-Free
(This forces Windows to use only the high-quality stereo profile)
- Right-click on the Start button → select Device Manager.
- Expand the section Sound, video and game controllers.
- Find your device that contains the words Hands-Free or Headset (e.g., [Your Model] Hands-Free AG Audio).
- Right-click on it → select Disable device.
- Repeat this for all Hands-Free devices if there are multiple.

We've run into a serious audio problem in Resident Evil 6 on PC that occurs only when using headphones. The sound becomes very strange, like the game is "in a bottle" or the audio is extremely distant. In Resident Evil 5, this issue could be fixed by simply reconnecting the headphones, but in RE6, when attempting to reconnect them, the sound disappears completely.

Attention: All common fixes, such as updating drivers, changing the sound format, setting Windows audio to Stereo, or disabling enhancements, we have already tried, and they did not help.

Does anyone know of a non-standard fix for this specific game, perhaps through editing configuration files? We would be very grateful for any help! (●'◡'●)