Vandersteen Sub woofers v Rythmik Subs


I really love the idea of the Vandersteen Subs where they are connected with the mains via extra speaker cable off right and left channels off the main amplifier, which is supposed to provide better bass transition from the mains while keeping the signature from the main amplifier. My question is with Vandersteen coming out with the SUB THREE and the price going significantly higher, I was wondering if there are other subs for less that you could integrate in the same way. (Most subs seem to rely on the line level input which is just a sub-woofer RCA going from the pre-amp to the amp on the sub). Can this same Vandersteen set-up be achieved with other subs?
I picked Rythmik since they are known (in the home theater community anyway) for being one of the best bang for the buck subs and the most "musical" of the bunch. (between Hsu, SVS, PSA).
And could I possibly achieve even greater sub-woofer nirvana since I could get an 18" for around $1500? Vandies only have 3 eight inchers.

I am a Vandersteen fanboy and I would like to support RV whenever I can, but don’t know much about my other sub-woofer options so looking for some feedback. Doesn’t even have to be related to Rythmik necessarily. If you know of other subs that can integrate the same way I want to know about it!

Thanks
bstatmeister
ctsooner and tomic601,

     I agree with both of you that subs outputting any bass in the 150 Hz range (I would even say any bass of 80 Hz or higher) is directional and can cause issues.  I've experimented with the Debra amp's crossover filter control, adjustable from 10 to 220 Hz, and definitely notice the bass performance and sound staging suffer when crossed over too high.  

     My Magnepan 2.7QR panels are rated as producing bass down to 34 Hz +/- 3 dB.  I think that's fairly accurate but have never measured them.  
     In my room, I've found a low low-pass filter setting works best and  I normally have it set at 40 Hz.  I realize theoretically that leaves an overlap between 34 and 40 Hz , since I run my panels full range, but it still sounds best to me.  
     All 4 subs are run as mono and none have their phase reversed; the Debra manual suggests reversing the polarity on 1 of the 4 subs progressively to verify the bass doesn't sound best in your room with the phase reversed on 1 of the subs.  My setup sounded so amazingly good with all in-phase that I never even bothered with trying this.
     I have absolutely no connection with Audio Kinesis but can honestly tell you that 'm thrilled with how well these dba systems actually provide true sota bass at a reasonable price. 
     You're probably thinking this dba solution sounds too good to be true.  I completely understand this reaction since I was so skeptical when it was originally described to me that I almost didn't buy it.  Thinking back to that time, it's a bit disconcerting how close I came to taking a pass on the Debra, due to cost and space concerns, and how fortunate I now feel that I decided to buy it.  
     It honestly works so well in my room and system that I can't think of any bass quality needing improvement.  I do believe 4 Vandersteen  Sub 9s would provide more bass than the Debra system but I'd really need to compare them to determine which produced better bass in my room. 
    Dbas are ideal bass systems for seamlessly integrating sota bass with any speakers, especially 'fast' panels.  I don't think I'm ever going to need another bass system, even if I switch my main speakers in the future.
Tim
great bass is amazing, so is state of the art imaging !
a 40 HZ filter is certainly low....not a ton of music down there...
what are you listening to with content down that low ?
i love The Organ Loft FM show...and of course the organ/ organist at our church...cool dude he sits in all over Europe when an organist goes on leave...
Rich, I listen to some cool new EMD stuff from Europe that my IEM buddies will send me.  Some info down below the 35hz range.  The Quatro's are crushing it to be honest.  One of my friends purchased 2 more of the older Vandersteen subs and set it up the same way the Swarm deal talks about and he's in love. Said he's in shock at how awesome the bass is with his Treo's.  He's said he may get the newer subs with the 11 band EQ like I have on the Quatros. We measured the bass in my room and it's pretty darn flat.  I may someday add subs, but getting Richards new mono blocks as soon as he gets them going (soon he said).  I want those in my system, lol.  Also the Thunder power cords are just about on order (need to just call to place order).  These Hurricane power cords have taken the system to a new level.  Noble, you should get a pair, lol. they will shock you I bet.  The Thunder may be all you need for the subs, especially if you are only running them that low.  
Thunder...I believe that is AC-DC song, lots of image depth on that one....
better left to the Cornwalls.....ha
LMAO...Those were one of the first high end speakers I heard when I was 9. The local guy where I bought my Yamaha YP211 TT/Grado cart, Yamaha CR 620 receiver and locally made/sold 3 way speakers carried Klipsch.   he had phase linear and Crown too.  That's what he drove them with. He also used a small tube amp, who's name I will never remember.  Corner horns were unreal.  Friends of mine got Heresey's .  I turned a lot of guys into audiophiles back in the day, lmao..