Thanks for the pointer, but no joy. The sound files for the tutorial do follow the guidelines laid out in the documentation, wav for SFX, OGG for background music. It's the OGG sound that comes out scratchy and distorted, but the file plays fine in any other media player, audacity, etc.
If you want to check what sound driver you're using, you can find it in Audio category in Project Settings. It seems to be a per project setting and not a program setting.
