I'm looking to buy a new receiver and his was on my list. My speakers are Kef THX ref's which have an impedance of 4 ohms. I have just rung Pioneer and spoken to their technical dept. I was told that in no way should the AX5i be used with speakers with a greater load than 6 ohms. He made it very clear that any damage done to the receiver would NOT be covered under their warranty. Bugger! Thought this may be of interest as I have seen the question on here before.