Long time no post.

My Axioms have been running fine for over a year now, until this weekend. I was watching Underworld DVD which has a very loud and dynamic 5.1 track, and during some of the shooting scenes I distinctly heard some crackling noise from tweeters on both the left main and center channel (mostly the center).

This is the first time I remember something like this happening. Now I am freaking out. I am hoping someone here can advise me if I have a speaker problem, receiver problem or just a problem in my head. Here are the details:

System -
Receiver: Onkyo 797 (with warranty replaced board for clicking sound)
DVD Player: Toshiba SD4800
Mains: Axiom M22ti
Center: Axiom VP100
Surround: Mission 77DS

I've tried other "sound intensive" movies and cannot recreate the problem. I've also tried to replicate the issue by playing music CDs and I think I hear something, but could all be in my head at this point. Volume levels have always been reasonable (well below reference levels) as I live in an apartment.

Thanks for any advice.