Well, after re-checking connections and woofer screws the other night, I rented Mothman Prophecies again and checked the scene with the phone ring. The distortion is still there. But I also played "musical centers" and hooked the center pre-out up to my left and right mains, and still heard the distortion. This tells me that unless I'm unlucky enough to have a problem with the same frequency in all 3 speakers, it's probably source related.
Going back to the 5th Element disc, I checked the "Opera" scene. Her singing is clean, but when the music kicks in and Leloo is fighting, I hear what sounds like possible distortion. But it's hard to tell since there's a lot going on sonically by that point and it could just be the soundtrack. I didn't have a chance to swap speakers for this scene, maybe tomorrow.
I've got the Diana Krall disc on order, so I'll check that when it gets here. I'm still a bit nervous about 2 screws being loose on that right tweeter, though. I guess for now I'll just keep a close eye on it.
