Vandersteen 3A sigs, whats wrong here.

certainly the out of phase issue should be looked at.

Daverz,

I just mentioned the wire because I do think 8TC is a bit lean and if a few other factors like setup and one other lean component (if applicable) could sway the sound to be thin and lightweight.

I have found system matching to be critical and balance can sometimes be difficult.

my two cents...

Alot of great answers above, if one of these do not answer your question, its possible a speaker problem. To put this all together, Start easy, check your speaker wires at the amp and the speakers, + to +, - to -. Next, temporarily move your speakers closer to the walls/corners, see if this brings out the bottom, next, you might want to slightly back your mid and treble controls down a hair on the back of the speakers.
My guess is as mentioned you are dealing with room nodes. You might want to do something like measure the room and use something like the "Golden Triangle" formula by Cardas for imaging. Placing speakers by its measurements do help get rid of room nodes. I suspect that you have gotten used to a bit of bass boost by your other speakers being closer to the walls. You can use the Golden Triangle, then if not enough bass, start moving your speakers, by a couple inches at a time toward the corners until bass reinforcement is where you want it, then adjust your tow in accordingly. I hope all of this helps. Tim

Hi, sounds like speakers, are out of phase, that's the most reasonble explanation, just check your wiring carefully, those speakers have no problem going down 25hz:

Cheers:

Could it be you are just used to hearing fat ported bass and the bass alignment in the Vandersteen with the passive radiator sounds comparatively lean? It's easy to find that fat sound appealing. It may also take some time to get used to the difference.

I can make large changes in my setup with a set of ASC tube traps. You might try experimenting.

"Start easy, check your speaker wires at the amp and the speakers, + to +, - to -. "

But if your preamp inverts the polarity, you'll want to connect + to -, and - to +.