Better sound after installing Snow Leopard??

I just installed Snow Leopard on my Macbook yesterday on a new Seagate 500 GB 7200 RPM HDD. I Also installed Windows 7 via Bootcamp with no notable issues. After playing with it for a while I noticed the system sounds were a little higher than usual (in OSX only), so I downloaded a few songs and browsed around YouTube for a while, and I saw (or heard) at least a 25% increase in overall sound volume. As I stated above this was only noticeable on the OSX partition; when I boot to Windows, all sounds are softer. Has anyone else noticed this? Could this be a driver update that improved my speakers' performance? Or is this an enhancement provided with SL?