I would leave it on 8 ohm, this question comes up a lot around here. What are the ohm ratings on your speakers? Many folks around here have Yammy's with the 6ohm Axiom 150 center and 6 ohm Qs8 surrounds, however, they still leave the switch on 8ohm.


M80s VP180 4xM22ow 4xM3ic EP600 2xEP350
AnthemAVM60 Outlaw7700 EmoA500 Epson5040UB FluanceRT85