Ticking while scrolling

When I scroll up or down, the internal speaker on my mac pro makes a really rapid ticking sound. Same happens on my PowerBook. Muting sound doesn't change it, nor does increasing or decreasing volume. Anybody else notice this?

 

Interesting! The ticking does sound like a really quiet version of the infuriating sound my computer makes when thinking about anything more than idle.

I thought it was a lousy fan, and it's driving me up the wall. If my computer was less than 14 days old I would return it and get my money back. I will need to do some digging and see if there is any way to fix this.