My receiver has connections for two speaker sets. Until now, I've only hooked up one set of speakers. I'm considering hooking up my old speakers and playing 4 speakers at the same time. Ever cautious, I consulted the receiver manual. Here's what Onkyo advises: "When you connect speakers to both SPEAKERS A and SPEAKERS B terminal posts and output sound from both speaker sets simultaneously, use speakers whose impedance is 8 to 16 OHM. Set the speaker impedance setting on the receiver to 4 OHM." This ruins all my fun. One speaker set is 8 ohm but the other is 6. Let's say I throw caution to the wind and proceed. Is it possible to damage my equipment by driving 4 speakers at once....particularly when those speakers are rated at different OHMs?