I recently started a thread about problems I've been having with Sony receiver (STR-DE597) going into protect mode. You can read about it here: http://forums.afterdawn.com/thread_view.cfm/129356 After borrowing a friend's multimeter, I found out my Klipsch speakers were *both* at a steady 4.0 ohms impedence whereas the Sony receiver recommends speakers that have 8 ohms impedence. So I'm guessing my speakers were manufactured improperly or else mislabeled. What I'd like to know now is could the receiver have caused this kind of damage to the speakers, a reduction in impedence? I usually use the stereo for background music--I certainly wasn't taxing the speakers' or receiver's limits. I was unable to find information on changing impedence online, but I did find something that said most receivers that are rated for 8 ohms can handle 4 ohms, which seems to explain why the receiver and speaker set up worked for awhile (approximately 3 months). But then should I also be concerned that the speakers have damaged/affected the receiver? I tried the receiver with 8 ohm speakers and it took me a few tries before it ceased overheating and going into protect mode. I'm wondering if I should send in the receiver--it's still under warranty and also only 6 months old--just to make sure that nothing's wrong. I suppose I shouldn't mention I was using improper speakers, though it seems that wasn't my fault, nor was it expected from a manufacturer like Klipsch. So I've emailed Klipsch and explained the whole sob story--I'll let you know what they say. I was told there is some way to alter the impedence of your speakers with a different sort of connection, but since the speakers are six months old and Klipsch, I'd rather have a new pair.