Did you find out what was causing your problem? I only ask for I have the 860 run a 5 speaker system, no subwoofer, including large towers. I have never noticed any clipping sounds from mine and I usually listen to movies around -25 to -35 depending on source material. At higher levels, -15, it can blow you out. You have 2 subs and that takes more strain off the 860. I don't know alot about all this but I have never had a problem like yours on my 860. How do you like the svs subwoofers? I thought about adding the sb 2000.