Choosing Sub-woofers. Please advise ASAP.

Sounds like a plan Tim.  As for using subs with the Quatros, there is no reason to do so.  That's the whole idea of his 11 band EQ built into them.  It's the same thing with his 7's.  He had just come out with subs for folks who have to have more bass with the 7's.  In order to get even more bass into the 7's cabinet you need to go external.  Physics says in order to move more air, you need larger cones or even more drivers.  I haven't hear the 7's with subs, but I will eventually.  Just waiting on a dealer to get them.  

Hi ctsooner,

     I understand that each Quatro speaker has a built in 11 band EQ for their built in self-powered sub.
     I assume you position each of your Quatros so that you achieve the best mid-range and treble response, along with the best sound stage illusion, at your listening position. I don't believe you're also positioning each Quatro for best bass response or even if it's possible to optimize bass, mid-range, treble and sound stage at one listening position even with the 11 band equalizers.  

     Because the built-in subs are located at the bottom of each Quatro just below the attached mid-range and treble drivers and it's known that bass sound waves interact within a room very differently than mid-range and treble sound waves interact within a room, I'm not understanding how it's possible to achieve optimal full frequency response at your designated listening position.  Can you explain how you do this in your room  without the ability to locate the bass drivers independently from the mid-range and treble drivers?

     I think you're only option is to position your Quatros for optimum mid-range, treble and sound stage performance at your listening position and hope the bass is also good with the subs in the Quatros at the same positions.  
     Do you just adjust the bass through adjustments on both subs' 11 band EQs and use trial and error? The supplied amp with the Debra DBA has an equalizer, too, but I have never felt there was a need for any EQ in my room so I just leave all bands set at 'flat'.

     If the EQs are your only bass adjustment method, I think your system is likely to really benefit from the addition of a couple Vandersteen QW subs(or their newer subs coming out).  Positioning these extra 2 subs might be a bit tricky since the existing 2 subs in your Quatros can't really be re-positioned.  
     However, I am not ruling out how effective 2 additional subs could be in your room even with the position of the first 2 subs' positions being set at their current position.  I think If the positions of sub#3 and #4 are positioned according to the standard progressive setup procedure used for the Swarm and Debra bass systems, you're likely to notice a substantial increase in bass performance at least at your listening position and possibly throughout your entire room.

    You seem very pleased with the bass and overall performance of your high quality Quatros.  But I hope you'll arrange a demo of this custom DBA at least give it a try in your room with your dealer. I'd be very interested on your thoughts on the results.


Good luck,
  Tim        

av123 mfw-15 hits frequencies that shake my entire house. I had no idea this sub would produce what it does.

Tim, I won't be bringing in any subs once I get the Quatro's in the house and set up.  What you also should keep in mind is that any of the powered Vandersteen's are set up for the best upper bass to treble response and soundstage.  Yes, that's right on their site I believe.  That said, dialing in the built in bass units using the EQ on each will give you probably 99% (always subjective) of what you would get by adding two more 2W subs and dialing them all in.  The dealer is doing the set up for me as most do.  They will use their lasers and tape measures, but they also have a special Vandertones disk they use to set them up for the bass.  It's really easy to dial in your bass this way.  All speakers are designed with omissions and have to be due to limitations set at price ranges or just due to materials available.  That said, I've never heard of a current or former Vandersteen owner from Quatro up complain about the bass.  I have a lot of friend who have standing wave problems, etc... get them in their room and be very very satisfied.  

Again, would adding two more be better?  Only if they match the speaker and are of the same design as the ones already in the room (in Vandersteen's case, using their 2W or better yet, his newest sub).  

Hi ctsooner,

     " That said, dialing in the built in bass units using the EQ on each will give you probably 99% (always subjective) of what you would get by adding two more 2W subs and dialing them all in.  The dealer is doing the set up for me as most do.  They will use their lasers and tape measures, but they also have a special Vandertones disk they use to set them up for the bass.  It's really easy to dial in your bass this way."

      For your sake, I hope you're right.  I do think the dealer should be able to optimize the Quatros' bass performance or optimize the Quatro's mid-range, treble and sound staging performance at a single listening position that you specify in your room. The difficult part will be doing both without compromising the performance of either. The lasers, tape measures, Vandertone disk and sub equalizers may help in this effort but the unavoidable laws of acoustical physics cannot be avoided even by the most skilled Vandersteen dealer.following the manufacturer's best setup procedures and using the most advanced tools in existence.

     My main point is simply that optimizing mid-range, treble and sound staging performance while also optimizing bass performance at a single listening position is not a simple process in any room.  This is especially true when the bass, mid-range and treble drivers for the system cannot be independently positioned in the room.  

     It is well known that bass sound waves propagate much differently in any given room, no matter its size or shape, than mid-range and treble sound waves propagate in the same room.  This is not a matter of opinion or debate.  It has been empirically proven time and again by independent acoustical experts utilizing controlled environments and following scientific methods.  

     These acoustical facts, unfortunately, equally apply in all rooms, including yours and mine.
     As long as the drivers launching bass, mid-range and treble sound waves into a room are positioned in the same speaker cabinet, the capability to optimize the reproduction of the entire frequency range in any room utilizing only 2 of these cabinets/speakers will be highly unlikely.  

     My opinion, based on personal experience and acoustical science, is not meant to disparage the Vandersteen Quatros..  I'm almost certain they'll be able to be positioned in your room to reproduce excellent mid-range and treble performance and an excellent sound stage at your listening position.  However, I'm fairly certain that your bass response at this listening position will not be optimized until 2 high quality subs, that can be independently positioned in your room, are added to your system.

     I believe a better design for the Quatros would entail 2 smaller towers containing the mid-range and treble drivers along with 4 small separate cabinets each containing one of their powered subs.  

     The Vandersteen dealer would first position the 4 independent subs in your room to optimize bass response in your entire room. The equalizers in each of these subs could be eliminated to save costs since I don't believe they would be needed in the resulting distributed bass array system.  
     The final step would be to position the 2 smaller towers to optimize mid-range, treble  and sound stage performance at your preferred listening position. 

     Assuming I think correctly that Vandersteen is unlikely to heed my design advice,I believe the next best option is to add 2 small but high quality subs instead.
  
   I wish you the best,
        Tim