I've looked through the Preferences and Advanced Preferences and I couldn't find anywhere the option to block the sounds from websites. I would like to listen to music while browsing, but every now and then a site starts singing or shouting ads at me.
You would have to block the ads in some way. A HOSTS file is good, but it can slow things down if it gets too big. A PAC may be better. http://www.schooner.com/~loverso/no-ads/
Some firewalls block ads.