Pro 80 problems

Yesterday, the woofer part of one of my pro 80s stopped working. I didn't really think much about it, thought it was a loose connection or something. Today I went out, and neither of the woofers are working, and the horns sound like crap.

My system goes rca input to ws420 to ht4 to pro 80s. I've deduced that its not the ws420, or headphone cord, I have yet to try different rcas, but I think its either something with the amp or crossover in the speakers themselves.

If I change the x over on the amp from hi to full, theres no change, and from full to low, nothing plays.

I'm trying to think if anything unusual has happened recently, but can't think of anything.

Any ideas?