Audio problem (echo-ish effect)

I'm not sure how to describe this problem, but my sound for all media and games is skewed. All of my sounds sound as though they were happening in a large auditorium, not exactly an echo but more of a broad, wide-open room sound.

I know this makes very little sense, but hopefully someone will understand what I mean. I have no idea what caused this, and have no idea where to begin searching for the cause of the problem.

Help?

 

I've had this problem. If a reboot doesn't solve the problem, then go into the program that controls you sound card's effects, and make sure they are all turned off.