Please email supportdos@larian.com, with a description of the problem and the report.zip file generated by the
D:OS support tool (for the PC version). The report will contain system and game information, any crash dumps, and your saved games (you could delete all but the latest from the zip to reduce the file size).
In the options, have you tried setting the FX volume to zero, etc?
For the Steam version, did you try verifying local files? In the Steam library, right click on Divinity Original Sin and select Properties, switch to the Local Files tab and then click on the 'Verify Integrity of Game Cache...' button.
Have you tried headphones as well as speakers, to see if there is a difference? If so, an audio setting change might help.