WOW! a lot of great replies..thank you all. Ive got a Rel sub connected via high output connection with speakon neutrik connector to my linn chakra amps. its a 2 channel system. Rel subs come with spike to screw into the feet, but odly enough the manual suggests Not using them. it integrates very well, sometimes seems a bit boomy/muddy. it sits about 8" from corner on carpet which is on top of slab...this is the ground floor, and no basement.
