I used to get the exact same thing in UT2004, man it was annoying!
In the end I found the problem in my case was a file sharing program called Apollon which includes a media player, if I used the media player at all then my games would have that delay and the only way to fix it was to run alsaconf. I think it was because the program was continually running so even though I stopped the media player it still had some sort of hold on the sound card, or something like that
. This might be because it was a KDE app and was using arts, I don't know, but you may want to look at any program which makes sound and keeps running in the background after.
On the other hand, I got this in FreeBSD too, but only with really old games, and I never found out how to fix that one
