i had that exact problem, just on XUbuntu.
the problem was with a 'fix' i had tryed for other sound problems. i undid it and all works well.
it was something to do with /etc/asound.conf, i used to have it blank, put stuff in there and it did this dlaying thing, blanked the files again, and is is good now.
try looking at that files, see what you have there.
or google that file.
EDIT: i just looked into that file, and thanks to
this website my sound works now, so thanks, and i hope you get it working soon.