My speakers used to do this thing where every so often when I played music, it would slow down and become choppy, briefly.
Now, a short term fix for this was to disable my USB wireless device, because for some unknown reason, that was causing this issue.
It's worth noting though that I don't think it happened on ths new, sick computer, complete with soundblaster card, and that it's definitely not happened since I moved house.
So to summarise, move house