As for what might cause it to sound muted - I have no idea - in general I would think that a silk dome should almost always sound muted or "polite" relative to a metal one. Generally a more "etched" or exciting sound is the way I describe how light weight cones tend to sound but this is a generalization.
I think the drummer might be holding the cymbal (which is what I meant by muting it). Usually I hear that effect mostly in the decay of the cymbal hit, but it seems like the attack isn't all there, or something in the attack seems off. I don't remember having that issue on the W/P8, and I won't have anyone around until this Saturday to switch the two again. I guess I could play them on my studio monitors, since they use a different material tweeter as well (Duh! I should have thought of that earlier...)
Thanks.