Your V2W may be operating out-of-phase with the main speakers. Try reversing the leads and see what happens. If that doesn't result in better bass response, then contact your local Vandersteen dealer (rather than call Vandersteen Audio -- Richard Vandersteen will probably direct you back to a dealer to resolve a problem like yours).
Vandersteen Sub not enought punch???
I bought a v2w vandersteen sub and I turned the bass up all the way and it still doesn't seem to have enought volume. I am using the top of the line audioquest innerconnect so that is not the issue. Before that I had a vandersteen 12" sub and it had about 75% more bass and punch this is in the same spot and everything and the volume is crancked on the amp and the gain on the sub is at max. I have a large room 18' x 20' is the room just to large for this? I really don't think a 12" velodyne should trump this sub what else could be wrong?