thanks for the replies

Doh! yes, I had the cables mixed up on the B side.

The other speakers are Cambridge Soundworks, not B&W.

They are a 3-way with an 8-inch woofer, so yes they do have more low end. I tried to compensate for this by putting them on the B side, which doesn't use the subwoofer on my receiver. Then the Axiom M22 was on the A side, using the subwoofer (I have a pretty basic onkyo 150 watt sub). Crossover is set at 80hz. In this configuration the Cambridge still are louder and "fuller", about a click or two on the volume different. so, maybe it's the two larger woofers making the difference.