Choosing Sub-woofers. Please advise ASAP.

     I need to make 2 corrections to my reply post earlier tonight about my DEBRA distributed array bass system:

1. Each sub contains a 10" woofer, not an 8" woofer.

2. The subs are connected in-parallel, not in-series.

Sorry,
 Tim

sautan904,

    You obviously have invested in some very good amps and speakers.  Getting a good bass system in place will complete the audio portion of your home theater.

     I think I'm the 3rd person to recommend multiple subs for the best bass performance both in terms of ensuring bass sounds good throughout the entire room (no bass peaks or weak spots at some seats) and quality bass impact. 

     A very good solution for you would be what's called a 'Distributed Bass Array System'.  If you google this name, there is a lot of info on this; the theory behind it explained by the acoustic engineer, Dr. Gettis,who 1st proposed it,  explanations of how it is applied and sellers of these systems..

     I purchased one of these bass systems for $3,000 called DEBRA from Audio Kinesis in Utah.  I was so impressed I started a thread here on Audiogon that describes my system and asks for input from others that have employed it.  Unfortunately, there aren't many current members who use it.  A good place to start would be to read this thread.  Here's a link to it:

https://forum.audiogon.com/discussions/anybody-else-using-a-distributed-array-sub-system?highlight=d...

      I was originally considering solutions like you are.  2 subs along the front wall at spots that are convenient.   I was looking at Hsu, Rhythmik, REL and JL that would be good for music and ht.  Fortunately, I discovered the distributed bass array system before I decided on specific brand and model of subs.  Here's a link to the site I bought the Debra at:

     http://jamesromeyn.com/old-pages/home-audio-gear/dsa-1-0-distributed-subwoofer-array-5-pieces-4k-usd...

     I was skeptical at first but, after many emails and phone conversations with James Romeyn, I decided to give it a try.  I justified the cost by rationalizing that 2 high quality subs would likely exceed the $3k cost of the array.

     The system consists of 4 67 lb  4 ohm  subs that are relatively small with 8" woofers that are ported.  The subs are powered by a 1,000 watt class A/B amp that has a variable  cut-off frequency control. There is an extensive and detailed setup procedure that instructs exactly where to place each sub in your room and how to wire the subs in-series to the amp.

     I know 8" woofers seem small but the 4 summed together produce excellent bass for both music and ht.  It's very versatile and can reproduce taut and nuanced bass for music and reproduce wall- shaking deep, powerful and sustained bass for ht that makes ht effects sound very real which can  be startling at times. The added bonus is that you won't have a bad seat in your room for great bass response and you'll have no need  for bass room treatments or  digital signal processing systems.

I'm not a dealer and I have no financial interest in distributed bass array systems or companies.

Just a big fan of this method,
   Tim 

     

sautan904,

     " 2x 12" it is.  Yes. My stereo system will be setup and professional tune for my listening area with acoustic treatment too.
home theater will be setup by another HT and Mcintosh specialist."

     Well, you made your decision and you'll soon know the consequences.  .   Are you saying one team is going to setup and  tune your room for music (including room treatments) and then another team is going to come in and setup the same area for HT?   

   If so and unless these 2 teams are working as 1 team from the onset and have a plan that understands the compromises that are inherent to having 1  area sound good for both, you may be headed for disappointment at the results.  
Will the setup, professional tuning and room treatments be geared in favor of music or HT?

Will the setup be geared to sound good at only 1 listening position or will it be geared toward sounding good at all seating positions in the area? 

How will the  2 subwoofers be positioned in the room to avoid the inevitable peaks and nulls that result from having only 2 sources of low bass frequencies in a room?  

Sound waves behave much differently in a room at 200 hz and below than they behave at over 200 hz.

 Attempting to produce accurate and extended bass performance throughout a room with only 2 subs (no matter what size subs or room), room treatments (no matter how extensive) and DSP (digital signal processing) has proven to be not only expensive but likely futile.  

Attaining good and evenly dispersed performance in your room on frequencies above 200 hz is going to be a piece of cake compared to attaining the same on frequencies of 200 hz and below. 

The inconvenient truth is that attaining good and evenly dispersed bass performance on frequencies of  200 hz and below in your room with only 2 subs is not going to happen.  

I'm sure you're skeptical but that's healthy and I was skeptical, too.  The proof will be evident once your setup has been completed; just play some content with repetitive bass and listen to the bass in each of the seats in your listening area.
 If the bass performance varies by seat position (bass is more prominent at some seats and lacking or even nonexistent at others) that means you have bass frequency standing waves in your area that result in peaks (overemphasizing the bass), nulls (underemphasizing the bass) and possibly cancellations (no bass percieved).

Okay, now the good news; When you realize the bass response varies by seat position, this is solvable through setting up a distributed bass system in your area that will result in consistently good bass response at all positions in your area.  Unfortunately, this means you're going to need a minimum of 3 subs (will work with 10" or 12" subs) and possibly up to 4 subs setup in a precise distributed array method.

This is all just the result of physics and  wave propagation laws that cannot be avoided.  Bass wave propagation within a room have been studied extensively by acoustical engineers such as Dr. Gettis and Dr. O'Toole.  They have published numerous white papers on bass wave behavior and experiments in various room sizes with supporting empirical results that have been independently verified multiple times.

The gist of their experimental testing conclusion is that the most effective method for reducing bass peaks, nulls and cancellations and attaining good bass response in any room is the use of distributed array bass systems.  The found that the more source points for bass (subs) in a given room, the better the quality and dispersion of bass becomes in that room.

Obviously, there is a practical limit to the number of subs in any given room.  Fortunately and crucially, they discovered there was a threshold of 4 subs in a given room that resulted in reducing the vast majority of peaks, nulls and cancellations in a given room and beyond which additional subs only resulted in  marginal improvements.  This is why the better distributed array bass systems typically consist of 4 subs.  

Hopefully, your setup teams will be familiar with the distributed bass array system procedure.  If they need assistance, I detailed the procedure in my linked thread on my previous post on this thread.  You can ignore the parallel wiring section since my system uses 4 non-amplified subs while yours will use amplified subs.  They'll just need to follow the sub positioning procedure and run line level cables to each sub and connect  the power cord to an electric outlet. I'd suggest hiding the connecting cables for aesthetic reasons ( I drilled holes in my floor and ran all cabling in the crawl space below. 

My motivation in posting on your thread and others is solely in sharing my knowledge about the effectiveness of distributed bass array systems and how well  it works in virtually any room to such an impressive degree.

  I consistently notice many threads that imply that they believe they can achieve good bass in their room if they only use a certain brand or size sub but rarely consider the number of subs and their precise positioning.  I increasingly think this is the case because of the simple truth is that most people don't know about distributed bass array systems and how well they work while  having the additional benefit of not requiring any room treatments, room analysis, equalization, DSP or any other tools and software many people believe is a good solution for achieving excellent and well dispersed bass performance in any given room.

     Again, I'm not a dealer of anything and have no financial interests in distributed bass array systems.
     I'm just an audio enthusiast who stumbled upon a great bass system method who wants to share the wordwith my fellow audio enthusiast brothers and sisters,   
   Tim   

Hi Al,

     Good point about the weight, 1,600 lbs is no joke.

      I have no idea what the weight capacity of a typical living or family room above a basement would be.  I would think it all depends on the supporting structure underneath.  If there were a few steel i-beams that are supported by a number of steel posts that are anchored into a basement's concrete floor, the weight capacity might be substantial.

      Do we know for certain there even is a basement below his room?
     If it's on a slab, the weight capacity could be extremely high.  

   Truth be told, the op is starting to tick me off.  I'm getting the impression he's not even reading my replies so I seriously doubt he'll listen to my advice and add 2 extra subs. I think he's asked for assistance but already has his mind made up of how he wants to do things.  .

     I'm fairly certain he's going to be disappointed in the results but I can only lead a sautan904 to water, right?.  If the yahoo doesn't want to drink, then he probably deserves a room with poor bass response.  

Later,
 Tim

akg-ca,

     I enjoyed reading your post on the Vandersteen 2Wq sub system  and I think it could be a very good bass system with a few modifications.  I especially like the subs taking their signal from the main amp in order to better integrate the overall sound with the main speakers..  Your post states:

" It is for all of the above reasons that there is only one subwoofer in existence capable of integrating seamlessly into a high-end music system, allowing you to reap all of the benefits of having a subwoofer, with none of the drawbacks."

       In order for this statement to be true, however, I believe the Vandersteen system would need to utilize 4 2Wq subs and utilize a much more precise distributed array method for locating each sub.  There was no mention of where to place their subs and simply placing them at convenient locations in the room will inevitably result in uneven bass performance throughout any given room.
       The only currently proven method to eliminate bass peaks, nulls and standing waves (providing accurate and even bass response throughout the entire area) in any given room is to use a minimum of 3 subs, ideally 4 subs, with each sub positioned according to the distributed bass array procedure.  
     I think the Vandersteen 2Wq system, with 4 subs and setup in the distributed bass array method, could perform equally as well or possibly even better than the Swarm or Debra bass systems.

Thanks,
 Tim  

          

  Dave,

     Very interesting how you're utilizing your 2 REL subs set to 'out of phase' to reduce bass standing waves in your room.  I haven't heard of this  before.  

     You state that this has actually reduced the perceived bass at your listening position but, due to the subs loading your room with low frequency sound pressure and your mains ability to go deep, this has resulted in an enhanced soundstage at your listening position.  

     I'm not completely clear on this but, since it's working so well for you, I want to learn more about this method.  A few questions if you don't mind:

1. How did you decide where to position  your subs, through a set procedure or trial and error?

2.  Can you be more specific concerning the sound qualities that result in your perception that the soundstage  being enhanced?

3.. Did you set it up so bass is best at your listening position, or so bass is good throughout the entire room?  

Thanks,
  Tim
 
 

Hi Dave,

     Thanks for the explanation.

     The method you used, playing the sub at your listening position and then walking (squatting) around the room to find the spot where the bass sounds best and then locating the sub to that spot, is the exact same method in the distributed bass array system procedure that I used to place my first sub.

      Doing it again for the 2nd sub placement, while the optimally placed 1st sub is playing, is also the step#2 that I followed.

     However, I disagree with your statement : " You can certainly compromise for a good "all-around" placement but it will only perform optimally in one location in your room for a given listening position."

     I think you're correct if only 2 subs are utilized in the room.  The DBSA (distributed bass array system)'s use of 4 subs in a given room is the key and I found it has the remarkable and empirically proven affect of eliminating all bass standing waves in a given room.  The result is optimal bass response evenly distributed throughout the entire room.  

     The only reason your good bass is limited to a single optimum listening spot is because you stopped halfway through setting up a DBAS in your room.  I am reasonably certain that adding 2 more subs, following the exact same positioning method you used for sub# 1 and 2, will result in the very good bass response, that you're now enjoying only at a single optimal listening position, expanded to every possible listening position in your room. 

     I'm a huge advocate of the DBAS only because I use it and know how amazingly well it works.  It is a system developed by 2 PHDs in Acoustical Engineering, Dr. Gettis and Dr. O'toole, that is based on math and physics and been scientifically and independently proven to be effective numerous times in various rooms.  

     Their published White Papers on their research and experimental results state that as the number of sources of bass wave propagation (subs) in any given room increases,   the number of standing bass waves in the room decreases.  They mention their realization that there is a practical limit to the number of acceptable subs in any residential or commercial space.  

      In a crucial statement about their findings as it relates to home and commercial usage, they also stated that they discovered that a minimum of 4 sources of bass wave propagation (subs) are required to eliminate the vast majority of bass standing waves in any room tested in their research results with any additional subs only resulting in marginal improvements.  This is the reason  most DBAS utilize 4 subs.

     My opinion is that the above is critical information for the original OP, sautan904, to consider when setting up his new system. I'm not sure whether he understands  the info, believes it  or has just chosen to ignore it, however, since he has opted to go with just 2 subs.  My concern is that he doesn't realize the results are completely predictable and inevitable regardless of your room dimensions.  

      When he discovers his 2  sub system results in numerous bass standing waves and resultant uneven bass response in his room, the good news is it'll still be solvable by an extra couple of subs.  

Tim    

Dave,

     You stated:" Nice to know Tim. Nothing like being set up by someone with an agenda to push posing as a real person. Shoulda known."

    My wife has often accused me of 'posing as a real person' but I didn't expect this from you!

     I'm such a big fan of DBAS that I've probably seemed a bit too enthusiastic to some readers.  I actually can understand how some may question my agenda.   My only 'agenda' is spreading the word on DBAS due to its extraordinary effectiveness in generating great  bass performance in any room due to its ability to eliminate bass standing waves without the need for ANY of the usual expensive but comparatively ineffective tools such as bass traps, room analyzing microphones, room analyzing software, bass compensating software or bass compensating equalization.

     However, I can assure you I have absolutely no financial association in the manufacture or sales of distributed bass array systems. After many phone calls and emails communicating with James Romeyn, the owner of James Romeyn- Music and Audio LLC in Utah where I purchased my DEBRA DBAS, I do consider him a friend but there are absolutely no business agreements or arrangements between us.  


Dave, you stated: " I only listen from one position as I am only one person at any given point in time. As for having four subs, I am probably already in the extreme at having two. I am sure there are a few audiophiles that are able to overcome the expense and freedom from real-life constraints (WAF and such) that can or will take advantage of your recommendations. Bet you can count them on your fingers.   You can stop trying to solve the issue for the OP as he went a different direction. One more finger in reserve..".
 

     I understand the OP decided to use 2 JL F112-V2 subs in his system.  For current and future readers of this thread, however,  I'm going to list the main reasons I believe this was not a good choice for many who are considering the best choice for low bass performance in their rooms and also to refute some of your comments in your quote above.:

1.  PERFORMANCE-

     I know the JL F112-V2 are very good subs. My issue is not with the quality of the subs the OP chose but the quantity of subs and their positioning.  As I've stated multiple times on this thread, it has been scientifically proven that 4 subs setup in the distributed bass array system method is the best solution discovered thus far at eliminating bass standing waves in any room regardless of the room's size and dimensions. This results in very good bass response  that is accurate, smooth, extended and these qualities are consistent throughout the entire room.  

The JL F112-V2 manual also recommends the use of 4 subs for best results.  Here is the exact quote:

" Research indicates that the smoothest bass response for a large listening area can be achieved using four subwoofers, placing one at the midpoint of each of the four walls (although using two or three subwoofers can be almost as good) "

     This quote is accurate with the exceptions  of the positioning recommendation and that 'using two or three subs can be almost as good".  .  The JL positioning  method is rather rigid and may not work in every room.  The distributed bass array method is much more specific and is customized to each  room.
     I am not aware of any scientific proof that two or three subs perform almost as well as 4 subs at reducing bass standing waves.  I'm  not stating this statement is false, just that I'm currently unaware of any scientific verification.of this statement.

     To be fair and honest, I think 4 JL F112-V2 subs would likely outperform 4 Audio Kinesis subs (probably in deeper bass extension) if both were positioned using the same distributed bass array method.

   However, using just 2 JL F112-V2 subs could possibly sound good at 1 listening position if both subs are positioned using the distributed bass array system procedure with the listening position treated as the reference position  But this will also unavoidably result in multiple bass standing waves at numerous other spots in the room that will cause bass perception at these positions to be exaggerated(peaks), diminished (dips or nulls)or even non-existent(cancellations).  Not a problem in your situation but is much more important to many others.

     

2. WAF-

     We all know this is variable by user dependent on the quality and nature  of your 'W'.  My opinion is that most wives would be more amenable to the look, size and discreetness of the Audio Kinesis subs than the JL subs. Here are some facts and I'll let each reader decide based on their own W's likely reaction:

Each JL F112-V2 weighs 117 lbs. and is 15.1"W x18.5"H x17.8"D
Each Audio Kenisis weighs 67 lbs.and is 14.5"W x 23.75"H x 10.375"D

JL F112-V2, I believe, is only available in black gloss finish
Audio Kinesis subs are available in a wide variety of wood finishes

My opinion is that the Audio Kinesis subs, being smaller and available in numerous wood finishes, would be considered by most wives to be more discreet than the larger and gloss black JL subs

     After following the progressive setup procedure, my front 2 subs sounded best located along the front 16' wide wall of my 23' long by 16' wide living room.  Each front sub is located about 1' away from each side wall, hidden from view by a 6' high by 2' wide Magnepan panel speaker that is positioned about 3' in front of each sub and also 1' away from each side wall.  From my listening chair located in the middle of the back 16' short wall  opposite  the front, both front subs are completely hidden from view.
     Sub#3 sounded best along the 23' long left wall about 1' away from the back wall.  Sub#4  sounded best along the right 23' wall about 1' away from the back wall.  Sub#3 is hidden from view by a large leather recliner and sub#4 is hidden from view by a large wooden end table that is between sub#4 and my listening chair.  Overall, the 4 subs do not call attention to themselves and, therefore,  very discreet.
     
  .  

3. PRICE/VALUE-
     . 

The complete Audio Kinesis DEBRA system(:4 subs and a 950W amp) is priced at $2,990.

 The mrsp of 4 JL F112-V2 subs(optimal performance according to JL) is $14,800, although a buyer buying 4 would likely to get a significantly reduced price of I would estimate at about $12,000. The OP would be very fortunate to have struck a deal for 2 JL F112-V2 subs for twice the price of the Audio Kinesis system. Clearly, using 2-4 of the JL subs is significantly more expensive. than the Audio Kineses complete system.

     I would think more than a handful of audiophiles would be interested in a bass system solution that outperforms 2 high quality subs, has a higher WAF and costs thousands less.

" One more finger in reserve.."?

Later,
Tim  

 


 .   

      . 

Dave,

"One more finger in reserve.."?"

    Cool.  Thanks for clarifying.

     I just wanted to put my thoughts down.  I know I have no control over what readers do with the info I give and that's fine with me.

     I think I'm just still a bit amped up on how well this system works for music and HT that I'm a bit too anxious to share the knowledge.

      I keep thinking my excitement of how well it works
will wear off.  But I've now had the bass system for about a year and it still makes me smile every time I listen.

Thanks,
  Tim

Dave,

     Thanks for the link.  Unfortunately, I found Raul's posts somewhat incomprehensible at times.  But that didn't stop me from posting a lengthy post on his thread earlier this afternoon spreading the word on distributed bass array systems.  I can't seem to help myself and you are now officially an enabler.

Thanks,
  Tim

In case anyone is interested, here's a professional review of the distributed bass array system I posted about earlier on this thread:
   
AudioKinesis Swarm Subwoofer System | The Absolute Sound

 This is actually about Duke Lejeune’s Swarm system but it’s virtually identical to James Romeyn’s Debra system that I own; exact same 4 (1 sq. ft. footprint by 2 ft. tall 4 ohm) subs with 10" drivers, 1,000 watt class A/B ampifier along with the exact same setup procedure and wiring method.

Tim

dlcockrum,

   You were right, that thread did keep me busy for a while.

    Unfortunately, I still feel the spirit and will likely continue to be a DBA (Distributed Bass Array) system disciple and spread the 'good word' about how well they perform compared to the use of 3 or less conventional subs no matter their quality or cost.

    I may be on a mission from the audio gods.

Thank you for being my enabler,

           Tim

ctsooner,

  I agree with much of what you posted: listening is subjective, audition and make up your own mind and some other statements.

  However, I think you have a misunderstanding of the main points I'm trying to convey. I'll attempt to clarify.

      The main thing I'm espousing is the concept of the Distributed Bass Array System  (DBAS as an acronym).  Specifically, the use of a minimum of 4 subs that are precisely positioned within a room in a progressive locating procedure in order to significantly reduce the bass standing waves throughout the room.  The result being excellent bass response, with no bass peaks (bass overemphasis), bass nulls (bass under-emphasis) or bass cancellations (bass absence), throughout the entire room and not just a single 'sweet spot'.

     What I am definitely not espousing is a certain brand or model of sub.  I know there are many very good subs because I've heard many of them.  Rel, JL and Vandersteen come immediately to mind when I think of some of the best I've heard but there are other very good subs as well.

     An important aspect of deploying a DBAS is that it can be done with virtually any make and model of sub preferred; the only restrictions being that 4 are required and they need to be precisely positioned within the room.  Good DBA systems are truly sub agnostic.

    The concept of the DBAS is typically credited to two acoustical experts, Dr. Geddes and Dr. O'Toole, who have written white papers and conducted empirical experiments on the subject.  I can provide links to their work if you'd like.
     The gist of their findings is that bass peaks, nulls and cancellations continue to be reduced within a given room as more bass sources (subs) are added.  
     They realized there is an obvious practical limit to the acceptable number of subs in a commercial or home environment. Critically, they discovered that the use of 4 subs strategically positioned eliminated the vast majority of bass standing waves within a given room, with additional subs being only marginally effective.  This is the reason most DBA systems utilize 4 subs.

     You're correct, my intent is not to offend anyone or denigrate their preferred sub.  My intent is only to bring awareness to how well the DBA concept works and the fact that absolutely no microphones, room analysis/room correction software or room treatments are required.

     I hope I've clarified my position,
          Tim   

ctsooner,

     
     As you heard at that high end store in NYC, distributed bass array systems work incredibly well.  They provide excellent bass response that is capable of being taut, textured, detailed and nuanced while also capable of going deep and powerful when the content calls for it.  Because of this, how they integrate so well with any quality or type of main speakers and work in any room no matter the size or shape, I consider them an extremely good bass reproduction system.  

       However, DBAs are not perfect.  A minimum of 4 subs are required to achieve this great bass response throughout the entire room.  Individuals must also make a few decisions before deciding to deploy a DBA in their room:

1.  Do they want great bass response throughout the entire room or just at one optimized listening position?

    The use of 1 or 2 good quality subs can be utilized, if positioned properly, to achieve very good bass response at a single listening position in a room typically called a 'sweet spot'.  The compromise of this approach is that bass response will not be good at numerous other locations in their room due to bass standing waves at those locations. The bass will sound exaggerated, under-emphasized or even nonexistent at these locations.
      The use of 4 or more subs in a DBA is the only currently known method that has been empirically proven to achieve very good bass response throughout an entire room.  
     The choice and ramifications are clear, either you find a way to accommodate the extra subs or you settle for very good bass response at a single sweet spot.

2.  Do they want a very good complete DBA system (like the $3K Swarm or Debra) or do they want to create their own custom DBA  (using 4 even higher quality subs of their own choosing that will be considerably more expensive)?

     I know of only one person, another Audiogon member enginedr1960, who created his own DBA using 4 Rel q201e subs.  He says it's working very well but I haven't heard it and he has never heard the Swarm or Debra DBA.

     I'm completely satisfied with my Debra DBA for both 2-ch music and HT.  However, I would think substituting other high quality subs in a custom DBA would likely sound as good or even possibly better.  Verrsatility is just another of the many benefits of the DBA approach.

     Yes, I am biased but only because I know it works so well.

     Tim  

ctsooner,

     I forgot to respond to the last part of your post where you stated:

" Yes, I like how Vandersteen runs his subs by taking the signal from the mains the way he does and crossing over where he does do the sound of the bass is consistent with the sound of the main speakers. I also like the idea of having a semi active speaker like the Quatro on up.  If done properly, it also will relieve the main amp from having to run anything from 100 or so down and that helps the amps sound better as they aren't having to deal with the bass load which is very difficult for any amp.  Lot's more dynamics current available for the mids which folks don't realize is where a ton is needed on transients."

     I don't disagree with anything you said.  I think your point about reducing the main amp's bass duties so they can sound better and have better dynamic range is important.
      I've never actually heard the Vandersteen Quatros but, from the pro reviews I've read and from your comments, I consider them very high quality speakers.  I'm glad you're enjoying them and I have no desire to convince you of anything except the benefits of a good DBA.  
     In fact, with a powered sub already existing in your room inside each Quatro,  perhaps you would only need 2 more subs to reach the required 4 sub minimum for a DBA in your room. A pair of carefully positioned Vandersteen WQs,  combined with the pair of subs in your Quatros, may result in a very high quality DBA in your room.

     I chose a somewhat different approach in my room.  I read some information from acoustical engineers that suggested, for best reproduction of the entire audible frequency range, any system should be constructed based on how various sound wave frequencies will interact with the room.  They explained how bass sound waves interact and propagate within any given room very differently from how mid-range and treble frequencies do so.  Basically, the lower the frequency the longer the sound wave produced. All sound waves are going to be reflected by room boundaries (walls, ceilings and floors).

     The only known and proven method for significantly reducing bass standing waves caused by the very long bass frequency sound waves reflecting off room boundaries and crashing into each other is the use of 4 or more bass sources (subs) in a DBA system.  This will provide very good bass response throughout the entire room.
      Unfortunately, the much shorter mid-range and treble frequency sound waves also bounce off room boundaries and cause standing waves.  But there's currently no known method for significantly reducing mid-range and treble standing waves so that very good mid-range and treble frequency response can be achieved throughout the entire room.  
     The only currently known solution is to optimize mid-range and treble response at a single listening position or sweet spot.  This is done via speaker positioning and angling as well as room treatments (absorbing and diffusing  panels) at critical reflection points.  The goal being that direct mid-range and treble sound waves launched from the speakers arrive at the chosen sweet spot location before (even milliseconds before) the reflected sound waves arrive.

      Because of the above, these acoustic engineers advise constructing a system from the bottom up.  First get the bass foundation right by installing a DBA consisting of at least 4 subs.  Then get the remainder of the frequency range right by installing your speakers of choice and optimizing their positioning and angling and room treatment for a given listening position 'sweet spot'.
     
     I followed this advice, installing the Debra's 4 subs for optimized bass response first and then positioning my Magnepan 2.7qr panels for optimum mid-range and treble response at my listening position.

     This works very well in my room and your method seems to be working very well in your room.

     We both did well!  
     More than 1 way to skin a cat, right?

  Tim   

Hi ctsooner,

You stated: 
" I think it's awesome that you love your sub set up.  I haven't hear the subs, but if you are getting 4 sub 1000 subs for 3k, I have to wonder if they will sound better than a pair of 1500 ea subs that are better quality (not all 1500 subs will be better quality, just making a blanket statement).  My other point is that most folks I know well could never have 4 or more subs regardless of size (and size does matter big time) in their rooms.  Life factors intervene as I posted above. Not debating the quality, just the cost, difficulty to set up perfectly and the ability to fit that many in their listening area (logistics).  That's all.  Not debating at all. "

     It is true that the Swarm and Debra DBA systems are reasonably priced at $3,000.  You get four small (1ft x 2ft x 2ft) but substantial (67 lb)  bass reflex  4 ohm subs with spiked footers and 10" drivers along with a 1,000 watt class A/B sub amp.  I consider these systems bargains given their price and performance.

     In my experience and room, the Debra system clearly provided better bass than my former 2 good quality older Kinergistics 12" subs were capable of.  My opinion is that either the Swarm or Debra four sub systems are likely to provide better bass in most rooms than the use  of  just a pair of subs no matter the price or quality.  I have not actually compared my Debra system to a pair of very high quality subs but would seriously doubt a pair would sound as good unless they were positioned to optimize bass at just a single sweet spot.

     Would the Swarm and Debra's bass performance  be improved upon through the use of 4 even higher quality subs  in the $1,500 plus price range?  Yes, I think this would further improve the bass performance of a DBA commensurate with the performance level increase of the substituted subs.

     I'm very curious how using 4 very high quality subs would sound in my room but I'm in no hurry to spend the thousands of dollars necessary to find out.  I'm currently very satisfied with the Debra's bass performance in my system with the supplied subs.  My concern with spending more in an effort for further improvement is the always present 'law of diminishing returns' in this hobby.  My opinion is that improvements would not be dramatic but marginal in nature and likely be hard to justify given the large expense.

     As to the point about most people not being able to have, or be allowed to have, 4 subs in their room, I consider this the most likely reason for the reluctance of many people to even try a DBA.

      I understand this concern all too well.  My wife thought I was nuts and we both thought we'd have to rearrange our living room to accommodate these 4 subs even though they're relatively small.  But I'm somewhat devoted to the performance of my combination music and audio/video system so I was persistent and managed to convince her to let me give it a try.
     Fortunately, I was able to position each sub where it sounded best while keeping their physical presence disguised (the front 2 hidden behind each of my 6' x 2' panel main speakers and the rear 2 partially hidden, 1 behind a leather chair and the other behind a large end table).

     Of course, not everyone will be able to locate 4 subs in their room as discreetly.  If this is the case,  each individual must determine how important very good bass response throughout their entire room is to them.  Those who think it's important will find a way to accommodate 4 subs.  Those who don't will need to use 2 or less good subs and settle for good bass at only a chosen single sweet spot.

Tim

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        

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  

ctsooner,

 " What you completely fail to understand is that 99% of anyone, will not be able to use 2 other cabinets in their room, especially since they too have to be placed in specific positions based on your theory."

       I'm beginning to feel like we both just completed our first lap in our ongoing discussion on Choosing a Subwoofer and we're heading back into turn #1 to run lap #1 all over again.  

      I don't know about you, but I'd rather not rehash points we already made in previous posts on this thread.

     I think we've both  already made our viewpoints on choosing a subwoofer clear.  

     I'm going to excuse myself from this thread by making a few additional points and summarizing my thoughts on this subject for posterity:

DBAs using a minimum of four subs have been scientifically proven to work incredibly well in providing excellent bass response in virtually any room of any size or shape.

Complete DBA systems, such as the Audio Kinesis Swarm and Debra systems, offer very good bass response at a relatively affordable price of about $3K.

Custom DBA systems can be created by anyone using four even higher quality subs that they prefer.  However, these may be considerably more expensive with possibly only marginal improvements.

If state of the art (SOA) bass response is sought, a DBA using at least 4 subs is required.

Those numerous Audiogon members and others that believe achieving great bass response is just a matter of finding the right brand or model sub and using 1 or 2 in their system will continue to be disappointed in the results not because their chosen sub is not good enough but because they used too few of them. 

Any bass systems not utilizing at least 4 subs will be a compromise according to acoustical experts and my personal experience. Systems using 3 or fewer subs may perform sufficiently well to satisfy their owners at a single designated listening position but allow too many bass standing waves to exist in their rooms to qualify as a SOA bass system.

Properly setup DBAs result in consistently very good bass response throughout the entire room, not just a designated sweet spot.  This makes it an ideal solution for HT use with multiple seating.

ctsooner has claimed that 99% of people will not be able to accommodate 4 subs in their rooms.  99% smells suspiciously to me like a POOMA number; a number ctsooner would likely admit under oath that "I pulled out of my ass". 

Anyone unable or unwilling to accommodate 4 subs in their rooms will, unfortunately, have to settle for less intrusive solutions that will have lower quality bass performance.

Those who are serious about attaining SOA bass performance in their rooms will find a way to accommodate the 4 required subs. 


 The distributed bass array (DBA) method was initially a theory proposed by 2 acoustical physics PHDs, Dr.  Geddes and Dr. O'Toole.   These 2 experts subsequently conducted scientific experiments that validated their theory and published a White Paper detailing the theory, testing method,  results and conclusions.  The gist of their primary conclusion was that bass standing waves, in a wide variety of room sizes and shapes tested, continue to be reduced as more bass source points (subs) are added.  They state that the majority of bass standing waves were reduced at the point that 4 subs were operating, with additional subs only having marginal affect.  

     As their results were consistently duplicated by other acoustic experts via independent scientific testing, the use of DBA systems to provide excellent bass performance in virtually any room transformed from a theory into a  proven and universally accepted solution among acoustic experts.

     I stated the above facts to make it clear that the DBA method is not 'my theory' but a theory proposed and proven valid by a couple of PHD acoustical engineers.

     Okay, I believe that summarizes my current thoughts on subwoofers and bass systems.  

    I wrote this likely final post on this thread with the intent to share with current and future thread readers what I've learned and the solution I ultimately discovered on my long journey to achieve excellent bass response in my system in my room.

    I hope this viewpoint will benefit others on a similar search.

Thanks,
   Tim   

Hi enginedr1960,

  "Tim you know you can lead a horse to water but you cant make him drink "

  Exactly right.  My sense is that many agree with the DBA concept and want really good bass response in their rooms  but find it difficult to drink/accept the 4 subs in their rooms.  Understandable but you seem to have found a way to fit 4 Rel subs in your room and you're now enjoying the benefits of a custom DBA.  Which Rel subs are you using? 

  " The rule is three is mandatory and adding the fourth is the end game any more and its a waste ."    

     Have you tried using 3 subs in your room?  I went directly from 2 to 4 in my room and never even tried 3.  I know Dr. Geddes mentioned the use of 3 subs in his White Paper and I'm curious how close you found the results of using 3 subs came to the use of 4 in your room.

     I'm very glad to know at least 1 fellow Audiogon member has tried the DBA system and has firsthand experience with how well it actually works.

Congrats and enjoy,
      Tim 

Hi ctsooner,

    You know my thoughts but it's, of course, your choice.
     I hope your system sounds great to you no matter which direction you decide upon.

Later,
 Tim

Hi ctsooner,

     No problem, we're cool.

Tim

Hi ctsooner,

   Understood and I hope you report back on your results.

Thanks,
  Tim