Windows has been degrading your game audio since the day you installed it.
Right click your sound icon and go to sound settings-> choose your playback device:
Format-> 16 bit (or highest) , 48000 Hz
Disable audio enhancements
Disable spatial sound (Windows Sonic on top of in-game 3D audio means two algorithms fighting over the same sound)
Every headset, every speaker, every IEM. All affected. All fixable in 30 seconds.
Screenshot below.
Heyo! Got some Toriel inks for y'all. Man, she really is an awesome/fun character to work on. again this piece is courtesy of @Hellsender316 . Please comment and enjoy... Oh, and commissions are open! ^^