Axiom Home Page Forums General Discussion Technical Questions Speaker hiss coming from QS8 tweaters

Hi, I'm having a bit of a problem with lots of hiss coming from the tweaters on my QS8s. There is also some hiss coming from the M60s, but it's not really audible unless the volume is very high or if I put my ear to the speaker. Here's my setup:

Pioneer VSX-1015TXK receiver
Axiom QS8 surrounds
Axiom M60 towers
14 gauge speaker wire at about 20 feet long
dayton banana plugs (probably dayton, not entirely sure)
source: xbox 360 with toslink cable/Sony SACD player with rca cables

I've routed all the wires away from electrical cords as best as possible. The receiver sits on the SACD player, and those are the only components in the area.

Any thoughts? I'm a bit of a home theater n00b, so I may have just overlooked something simple.