Disabling specific things like Dolby, DTS or EAX may partially make things better. Generally, sound is harder to tweak assuming it functions relatively correctly initially. Issues like auto-volume reduction are still unfixed practically. But there are way more functionality problems. In the newer 8.X and 10 versions, it's even a worse quality (but not that of a big decrease like from XP to Vista/7). Even good tweakers like SRS lost a lot of possibilities. If sound could be considered quite of good quality in XP, in Vista and 7 it lost a lot of quality due to the multiple OS layers interfering with the actual sound card functionality.
Overall sound quality and functionality decreased with each major windows version since XP.