Hello,
I had an issue with sound which I assume happened after the newest Windows update. The sound started to be weird and I didn’t know if it was just me or if there is an issue. Turns out that sound has automatically changed to 7.1 in the settings instead of stereo. I has always been playing on headphones and never used 7.1 on my computer. I searched in windows sound settings but nothing has been changed there. The speakers were always set on Stereo but the game kept changing it to 7.1. You can find some of the screenshots in my tweet: https://twitter.com/Liquid_MaNa/status/1171920312394485760
However, what fixed the problem for me was changing the speakers from Stereo to 7.1 and back to Stereo, then Starcraft started to read the speaker setting as stereo.