Your system might be a case of too many cooks. You got a lot of self-powered bass drivers, and in these situations you'll typically get a lot of boom for the buck. But, your comments about lack of weight indicate that you might also have some bass cancellations going on at your listening position, which you can try to remedy by repositioning the speakers and/or the subwoofers, or moving your listening position to a different location. Another problem with four separate powered bass drivers is that you have to adjust the gain for each of them.

The Studio series is noticeably more refined and has better overall balance than the Monitors. The Monitors are brasher sounding and lot more aggressive, but also more uneven overall. I'm generally not a fan of powered tower speakers. The ones I've heard are overly boomy sounding, and the middle of the wall is usually not the best place for optimal bass performance. So, maybe just switching to a passive main speaker and more carefully setting up the subwoofers will give you the sound you're looking for.

I would actually suggest that you do some lower frequency measurements. Your bass might also sound lean because the overall level is actually lower than it should be, but peaks at certain frequencies make the overall sound boomy if you raise the levels any higher. Boominess is often caused by severe peaks at specific frequencies, and you can eliminate those peaks through room treatments and/or parametric equalizers (like the Behringer Feedback Destroyer). Once you eliminate the peaking, you can raise the overall bass levels, resulting in a fuller and more even sound in the lows.

The Studios are very versatile performers, and your Denon should have more than enough juice to really crank them through the motions. The 100 I've heard is more taxing on amps, but the 3801 should still have enough for those beasts. If you go with the 100s, you may not even need a subwoofer. Depending on the size of your room, you might also want to start with one subwoofer like the Servo-15. Going with one subwoofer makes it easier to optimally position the unit and use a parametric equalizer to correct for room acoustics.

I own the Studio 40 v.2s and did an extensive listening to the v.3 versions recently. My impressions are posted below.

http://forums14.consumerreview.com/c...966@.ef9e447/8
http://forums14.consumerreview.com/c...967@.ef9e447/0