
So, without having any knowledge on the subject, I believe the problem is somehow connected with Win10, my motherboard and the Realtek Audio Drivers. In this article, we have explained two easy methods that will help you to change the sound audio balance for the left and right channels in your Windows 10 PC. But, as you may have guessed, it is back. Suddenly, on a PC restart, the problem was solved again. I once again ran through the fixes, fiddling with audio settings, and uninstalling and reinstalling various drivers. By following the various fixes from these various cases, I eventually solved the problem by uninstalling my Realtek Audio Driver and installing an older version. I googled extensively on the problem and found a few (very few) cases with a similar problem.

Sometime last month, the problem suddenly appeared. The story so far: I bought and assembled my PC in January. (This also happens when I use an USB-adapter for the headphones, so it is not the audio-ports that are the problem.) So the problem is unfortunately not solvable by just adjusting the balance. Specifically, the left speaker/headphone is lacking in bass and other deep sounds.

The problem: Audio balance is wrong on all audio devices plugged into the PC. Speakers in back audio-port, headphones in front
