Help me understand "the swarm" in the broader audiophile world


I'm still fairly new out here and am curious about this Swarm thing. I've never owned a subwoofer but I find reading about them--placement, room treatments, nodes, the crawl, etc--fascinating. I'm interested in the concept of the Swarm and the DEBRA systems, and I have a very specific question. The few times I've been in high-end, audiophile stores and asked about the concept of the Swarm, I've tended to get some eye-rolling. They're selling single or paired subwoofers that individually often cost more and sometimes much more than a quartet of inexpensive, modest subs. The same thing can be said for many speaker companies that make both speakers and subs; it's not like I see Vandersteen embracing the use of four Sub 3's. 

My question is this: do in fact high-end stores embrace the concept of multiple, inexpensive subs? If not, cynicism aside, why not? Or why doesn't Vandersteen or JL or REL and so on design their own swarm? For those out here who love multiple subs, is it a niche thing? Is it a certain kind of sound that is appealing to certain ears? The true believers proselytize with such zeal that I find it intriguing and even convincing, and yet it's obviously a minority of listeners who do it, even those who have dedicated listening rooms. (I'm talking about the concept of four+ subs, mixed and matched, etc. I know plenty of folks who embrace two subs. And I may be wrong about all my assumptions here--really.)

Now, one favor, respectfully: I understand the concept and don't need to be convinced of why it's great. That's all over literally every post on this forum that mentions the word "sub." I'm really interested in why, as far as I can tell, stores and speaker companies (and maybe most audiophile review sites?) mostly don't go for it--and why, for that matter, many audiophiles don't either (putting aside the obvious reason of room limits). Other than room limitations, why would anyone buy a single JL or REL or Vandy sub when you could spend less and get ... the swarm? 


northman
Proving the superiority of a multi subwoofer setup is easy. All you have to do is impulse test the system at three set positions in the room using one then four sub woofers. What you will see with one sub is wide changes in volume between 0 and 100 Hz  up to 10 dB or so between the positions. With all four subwoofers these variations will reduce to less than 3 dB. Even with room control you will have trouble. Trying to correct a 10 dB deficit will cost you 8 times the power and force the woofer into the non linear part of it's excursion creating distortion. Correcting a 3 dB deficit requires just twice the power and a much smaller increase in woofer excursion. Put all this together and the ultimate subwoofer system requires 4 large subwoofers with at least 2000 watts of power each and room control.
This might have been asked/answered up above, but I didn't feel like reading the entire thread.

So if you have three subs that are all powered, what is the best way to integrate these into the chain?  Especially if I wanted to connect them all at speaker level. Can these be piggybacked somehow so you don't need individual speaker cables from each one running to the main power amp?

Oz



why doesn't Vandersteen or JL or REL and so on design their own swarm?

You can build a Swarm/dba with those brands or any other brand for that matter. All you have to do is buy three of more and place them asymmetrically around your room. You can even use multiple brands and sizes if you want.

Hleeid wrote:

"Interestingly, the DBA provided the greatest percentage of improvement in the smaller room."
It probably seems highly counter-intuitive that a SMALLER room would benefit the most from having a LOT of subs, but the explanation is pretty simple:

Smaller rooms start out worse, and therefore have more room for improvement. Bigger room + DBA is still better than smaller room + DBA, but the gap between the two is reduced relative to what it would be with more conventional approaches.

By the way, kudos to Hleeid for his creativity in figuring out a way to shoehorn four subs into that 10x12 room. I would NOT have thought his situation met the "practicality" test, but the dude was determined. Hleeid certainly expanded my perception of what’s possible.

Audiorusty wrote:

" You can build a Swarm/dba with those brands or any other brand for that matter. All you have to do is buy three of more and place them asymmetrically around your room. You can even use multiple brands and sizes if you want."
Yup!!

Ozzy62 asked:

"So if you have three subs that are all powered, what is the best way to integrate these into the chain? Especially if I wanted to connect them all at speaker level. Can these be piggybacked somehow so you don’t need individual speaker cables from each one running to the main power amp?"  

If the three subs all have speaker-level inputs, they can all be driven in parallel by the main power amp. The exact cabling configuration would depend on the layout in your room, but if you wanted just one set of cables connecting your amp to the first sub, then a second set connecting your first sub to the second sub, then a third set connecting the second sub to the third sub, that can be done.

The speakers cables running to the subs’ inputs can originate at the speaker terminals instead of at the amp terminals, if that helps. Also, these cables can be very thin, as the signal they carry is in the milliwatts.

Duke
The idea that only swarms can sound good, or are the ideal fix for any possible ailment your system has is just not supported by evidence.
I do not believe anyone here is making that claim. I'm an advocate of using the Swarm because it fixes bass issues by breaking up standing waves in the room, something that can't be done easily with both room treatment and bass management combined.


But I have more than one system in my home. My bedroom system only has one sub, and by careful placement I got it to work great in the 'listening chair' :)   But the sub in that case is not intuitively placed (such as in between the main speakers) and the bass cannot be heard throughout the room even though the rest of the system is.


In a nutshell, we are talking about an advance in how bass reproduction is done in the home and the advance that a distributed bass array represents is major compared to the prior art.


Accepting what science does can be really helpful. It can help keep you from getting sick. The results of science has allowed people to fly around the world. It allows light in the dark at a flick of a switch. It allows amplifiers to sound like music. In the legal world, there is a principle called 'dirty hands' which in a nutshell works like this: 'you cannot reserve a right for yourself that you do not also confer to others.' The idea that one can accept science to allow for light in a room but not accept science to allow for proper bass reproduction is to me simply ridiculous.
erik_squires
The idea that only swarms can sound good, or are the ideal fix for any possible ailment your system has is just not supported by evidence.
atmasphere
I do not believe anyone here is making that claim ...
But that is exactly the claim that some have made:
millercarbon
Surely no one with the room, who takes the time to compare, would ever choose anything else. No one has. No one ever will. The difference is so night and day that Duke had one customer with a $30k subwoofer budget decide to buy the Swarm. Not even a $30k sub can match a $3k Swarm.
So there’s your answer ... Because since we all know no one or two subs can ever touch a DBA, then not only do the high-end dealers make money selling you the one sub that can’t work, they get to sell you another ... sinnce you already know DBA works, and yet is not widely adopted, then you know how good they are at selling audiophiles on stories ... Why would anyone buy a sub? They don’t. They buy a story
And here’s another:
mijostyn
Proving the superiority of a multi subwoofer setup is easy ... the ultimate subwoofer system requires 4 large subwoofers with at least 2000 watts of power each and room control.

One SW12 provides satisfying high quality mono bass. Two SW12's produce more realistic stereo bass, higher levels, and better smoothness. Three SW12's add front / rear information and truly envelope the listener in bass.

@mitch2,
Your above quote from Aerial’s Michael Kelly is very similar to a multiple sub white paper excerpt here:

Subwoofer setup after Earl Geddes (GedLee LLC)

The multisub setup described on this page has two big advantages over other methods: only three subs are needed and you don't need to put the subwoofers at specified locations. Nonetheless there are some basic rules that have proven to yield best results:

Put one sub in a corner close to the mains. The second sub is a lot more flexible as to its location, but it should not be in a corner. Side wall or back wall, near the midpoint is a good idea. Put the third sub wherever you can that is not too close to the other two. It's a good idea to get one of them off of the floor.

Subwoofer requirements

Because we are using 3 subwoofers, they do not need to be as powerful as a single subwoofer. Any decent active subwoofer (ported or closed design) with a 10" or bigger driver will do. It should have controls for

  • level (continuously variable)
  • low pass frequency (continuously variable)
  • phase (switchable or continuously variable)
  • parametric equalizer (optional)
I’m an advocate of using the Swarm because it fixes bass issues by breaking up standing waves in the room, something that can’t be done easily with both room treatment and bass management combined.
You forget Active acoustical device controls...

People dont realize that bass dont exist in his bass world.... All frequencies are linked together in the acoustical space...

The easiest low cost way to improve bass is to improve the acoustical settings controls of the room not only passively but actively...

The idea to improve bass with woofers BEFORE improving the room acoustic baffle me.... Sorry....

What do we want a better sound musically or a bigger bass?

I dont doubt that the swarm is a good idea, read me for what i said....

It probably seems highly counter-intuitive that a SMALLER room would benefit the most from having a LOT of subs, but the explanation is pretty simple:

Smaller rooms start out worse, and therefore have more room for improvement.
This affirmation is comical in a way....If you are a shorter man you will benefit the most from a larger suit!

The truth is acoustical treatment and active controls change a room, bass included....The suit fit the individual so to speak....

I am sure that Swarm is a good idea, i repeat, but for most people not a good one at all, because impractical, and costly, and changing the acoustic dont begin with the bass obsession....

I mute myself now.....
So if you have three subs that are all powered, what is the best way to integrate these into the chain? Especially if I wanted to connect them all at speaker level. Can these be piggybacked somehow so you don't need individual speaker cables from each one running to the main power amp?
Perchance, did anyone see this important question?
Ozzy62 wrote: 

" Perchance, did anyone see this important question?"  

Did you see my answer? 

Duke 
Oz, you are quite welcome.

Cleeds wrote:

" But that is exactly the claim that some have made: "

Do you really mean "EXACTLY"?

Because imo that is open to dispute. Not that I necessarily think squabbling about the meanings and implications of words and sentences will settle anything. 

How about this: 

Cleeds, can you articulate the core of what your objection is? THAT might be worth talking about, as we might be able to reach mutual understanding.

Duke
@tyray
Your above quote from Aerial’s Michael Kelly is very similar to a multiple sub white paper excerpt here:
Earl Geddes was Manager of Advanced Audio at Ford Motor Company here in Michigan and has a PhD in Acoustics, while his wife (and partner in their mostly dormant company GedLee) Lidia has a PhD in Audiology and teaches at Eastern Michigan University. Earl’s Ph.D thesis was on the acoustics of low frequencies in small rooms, so he should know a thing or two about subwoofers and bass behavior in audio rooms.
If you want a fun read, take a look at their Dagogo interview from June of 2012. Below the link, I have included some interesting quotes from the interview that apply to the issues discussed in these Audiogon threads every week.
https://www.dagogo.com/an-interview-with-dr-earl-geddes-of-gedlee-llc/
Quotes from the interview:
  • Perception is what we want to know, but since these are human perceptions there is a huge array of external biases that get involved.
  • But the real point here is that someone is not a good judge of sound quality just because they think that they are –
  • I came to conclude that the more someone claimed to be a “golden ear” the less likely it was that they actually were.
  • For the most part I have found that most audio dogma and folklore is simply incorrect. Audio is like a religion, most aspects of its fundamental beliefs are accepted on faith and most supporting rational is constructed in such a way as to be untestable.
  • Uncontrolled listening tests won’t get you there, that much is certain. These types of tests have a strong bias towards change for change’s sake (among numerous others) and as such have a tendency to go in circles.
  • After working in this area for a long time, I have concluded that the very common phrase “I know what I hear!” is simply incorrect. The fact is that people do not have reliable perceptual capabilities when it comes to sound quality. .....Many people will completely discount any and all scientific facts if they contradict a closely held personal belief.
Mitch2 wrote: 

" Earl’s Ph.D thesis was on the acoustics of low frequencies in small rooms, so he should know a thing or two about subwoofers and bass behavior in audio rooms."  

Earl was my mentor, and I use an early version of his ideas about distributed multisub systems, with his permission. 

Duke
Let’s clear up a few things, Vandersteen has been offering a unique powered bass system w 11 bands of Analogue EQ for at least 20 years now. Of course as an advocate of real science Richard is familiar w Geddes research and his own that formed the basis of his unique design. In fact those paying attention will remember Richard passing his congratulations on to Duke for his work and award. You can of course use multiple subs in the Vandersteen ecosystem of high passed speakers with built in or external subs. Perhaps some will recall system 9 subs at Munich ( best of show sound ).
The Vandy way preserves the transfer function of your main amp, has more cut than boost, the 11 band EQ is NOT octave based but based on empirical sampling of typical listening room nodes, and super importantly designed to give fantastic bass at the listening position ( gee where the rest of the stereo image is - for a company fanatical about time and phase since 1977 imaging is a super high priority. Finally in my system photos you can see an RTA photo of bass fundamentals and harmonics.... image destruction starts  below 200 HZ, so you might want to watch that sub integration and placement carefully.
oh ya, of course I have heard a DBA :-)
What I don’t understand is why do people on this site always verbally attack Duke for just being a businessman, entrepreneur and fellow Agon poster?

You don’t have to try, buy or use the swarm, but all the keyboard internet negativity is not warranted and shows some lack of civility.

What ever happened to just having discussions amongst adults who enjoy this hobby? You don’t have to have the swarm or even like the swarm, but to attack Duke for trying to make a living everytime this subject comes up? Is nothing more but and act of hiding behind your moniker cowardice.

I know some posters here can be abrasive, but sometimes it just takes the bigger man to be just that. The bigger man. Don’t attack Duke on account of or for the sake of others.

I was really hoping that there maybe some sort of down to earth shootout? Or are you guys just gonna flap your gums at Duke? Some of you guys take the fun out of every subwoofer thread every time the words swarm or subwoofer is brought up.

I like to bring something positive to this thread and congratulate Duke on his hard work to be an engineer, salesman, tech, phone person and everything else it takes to run a business. 

And everytime the swarm is brought up here in Agon I do see new customers that have bought your swarm and report their experiences back to us here on Agon.


What I like about the above quotes, mitch2 took the time to find them, read them, think enough to understand what might be of particular value, then cut and paste here with a link. 

Sweet.
And for perhaps only the bass players atwixt us ( Duke and me and ? )’perhaps we can also agree there is more to world class bass than flat frequency response ?

and Duke, IF I haven’t said it enough, congrats dude !!!!!
And has anybody done a swarm with Longbow ? Hint Duke that might be a way to bring more into the fold...
The idea that only swarms can sound good, or are the ideal fix for any possible ailment your system has is just not supported by evidence.
atmasphere
I do not believe anyone here is making that claim ...
But that is exactly the claim that some have made:
millercarbon
Surely no one with the room, who takes the time to compare, would ever choose anything else. No one has. No one ever will. The difference is so night and day that Duke had one customer with a $30k subwoofer budget decide to buy the Swarm. Not even a $30k sub can match a $3k Swarm.
@cleeds I think if you reread these comments above you will see that I was correct. You see Erik's comment which opens- now compare that to Millercarbon, you see that the latter says its *better* (in his own words) and that if able to compare, people would choose it, but that does not negate my comment in response to Erik's comment. Now I've been often accused of being very specific, but I also spent a lot of time in English writing courses in college. Perhaps that is part of why I am so specific, but what seems to be agreed by all is that one sub can sound excellent if set up correctly, but if a DBA is set up its a lot easier to get it to sound right and that it might even sound better than 'excellent'. 'Excellent' and 'best' are two different things and I've not seen this conversation derail down that rabbit hole. Yet.
atmasphere

@cleeds I think if you reread these comments above you will see that I was correct ...
I think the quotes I provided speak for themselves. I'm comfortable with letting each reader decide this matter for himself.
audiokinesis
Cleeds, can you articulate the core of what your objection is? THAT might be worth talking about, as we might be able to reach mutual understanding.
I don't have any objection to swarm or DBA systems at all. None.
Some of its advocates are effusive in their promotion and it looks pretty silly. That is all.
tyray
... why do people on this site always verbally attack Duke for just being a businessman, entrepreneur and fellow Agon poster? ... all the keyboard internet negativity is not warranted and shows some lack of civility ... to attack Duke for trying to make a living everytime this subject comes up? Is nothing more but and act of hiding behind your moniker cowardice ... Don’t attack Duke ... are you guys just gonna flap your gums at Duke? ...

I don't see anyone on this thread "attacking" Duke, so I really don't understand your indignation.
Cleeds wrote:

"I don’t have any objection to swarm or DBA systems at all. None. Some of its advocates are effusive in their promotion and it looks pretty silly. That is all."

I understand. Thank you for clarifying.

"I don’t see anyone on this thread "attacking" Duke, so I really don’t understand your indignation."

Tyray stuck his neck out for me, and I appreciate it.

Duke
@mitch2,

It took me a very long time to wrap my head around having more than 2 subs. I was from the school that says you always put your subs in the corners about 6 inches or less from the walls in symmetrical positions. And you only need 2.

When I first read the above excerpts I took the sub farthest away from the mains and put it in the middle of the opposing wall. I then took the sub that was closest to the mains and turned it 45 degrees. Well to my surprise they did sound better.

Then reading more in agon Duke did suggest to the things he told you to do with your subs, then I can't remember if it was Duke on some other reading but 'if you can raise one up towards the ceiling'. What!

So after about 30 seconds of trying figure out how to get a 60lb sub up to the ceiling I started to think out of box as it were as to the typical placements of subs in only the corner that we are so used to doing.

I had an old SVS sub in the closet to make a total of 3 subs and put it on the back in the middle of the wall. I borrowed a smaller smaller sub to put on the highest shelf in the back of the room. It made a difference.

Was it a swarm? No but it did open up my thinking just a little more of having 4 subs placed in my listening/tv room. Now all this didn't just happen overnight as I had to get F connectors and cable and hook everything up.

When it was suggested I put a sub up towards the ceiling, I didn't think this s**t would work and almost didn't try it. I'm glad I did.

And to this day I don't own the swarm for the same reasons you don't own the swarm. I already had money invested in subs. But the science does work.
northman,

     I've been monitoring this thread and realized I had the urge to reply to almost every post, because I thought my comments would be beneficial to the posters, but have successfully been resisting these urges until now.  
     I've changed my mind, however, and now believe citing a previous post and adding my comments will not only be hopefully beneficial to the posters, but it will likely also help you in your quest to better "understand the swarm in the broader audiophile world".
     Before I begin, I just want you to know that I'm just a fellow Audiogon member and AK Debra complete DBA kit user who's a big advocate of the multiple sub concept in general and the 4-sub DBA concept in particular.  My comments are solely based on my personal knowledge and experience gained by researching multiple sub theories and concepts and trying them out in my own system and 23'x16' living, 2-ch music listening and home theater room.  Basically, I'm just an A/V hobbyist with no formal relevant schooling, training or A/V company affiliations that believes in full disclosure.
     Okay, enough of that, below I'll list the poster with their partial post quote and add my comments below each.  My current thinking is that this format could be beneficial to multiple thread participants but also that I could quickly get in over my head.  My intention is not to hijack this thread but to summarize, clarify and to assist the OP in better understanding the swarm concept:    

mapman:
 " Audio Kinesis (Duke) is also very knowledgeable and big on sound dispersion in general and I believe tries to enlarge that sweet spot with his designs. When that is the case ( a larger sweet listening area) the case for a more evenly distributed bass is also better."

     I believe this is generally true but wanted to add specifically how I implement the swarm since my goal was to broaden the bass sweet spot in my room for HT but to restrict  the midrange, treble and stereo image to a traditional sweet spot, meaning a pair of main speakers precisely positioned in relation to a single designated listening seat to optimize the midrange, treble and stereo sound stage illusion. 
     Here are some relevant facts to consider:
-Deep bass frequency tone sound waves are omnidirectional and exceptionally long (a 20 Hz very deep bass sound wave is 56' long).  
-Humans typically cannot localize (tell exactly where the sound is coming from) bass sound waves with frequencies below about 80 Hz and down to the audible limit of 20 Hz. 

-Midrange and treble frequency tone sound waves are highly directional and decrease in length proportionally as the tone frequency is increased (a 1,000 Hz midrange sound wave is 1.13' long and a 20,000 Hz very high treble sound wave is a fraction of an inch long).
- Humans are typically very adept at localizing midrange and treble sound waves beginning with frequencies above about 80 Hz and up to the audible limit of 20,000 Hz.
- Sound waves from 20 to 80 Hz are mono and perceived by us as mono  whether separate L +R channels exist or not. 
-Sound waves between 80 to 20,000 Hz are actually mono but perceived by us as stereo if separate L + R channels exist.
-All sound waves continue to bounce, or reflect, off of room boundaries (walls, ceiling and floor) until they run out of energy, are absorbed or are diffused.
-Humans require at least one full cycle sound wave to exist in the room to perceive any sound no matter the frequency.  Additionally, humans require multiple full cycle sound waves to exist in the room to perceive a change in pitch.  This only becomes an important factor on some very deep and very long bass frequency sound waves, which can potentially exceed the length of a room's dimension, and require a room boundary reflection for the full cycle length of the sound wave to exist in the room before being perceived, along with multiple sound waves existing to notice a change in pitch. 

    The above facts result in bass sound waves behaving, and being perceived by us, very differently than midrange and treble sound waves in any given room.  Because of this, I decided to take the approach of treating my system as two systems: a bass system and a midrange/treble/imaging system.  
     The bass is typically the hardest to get sounding right in most rooms.   My main point is that,  while the Debra  delivers near sota bass in mono throughout my entire room that serves as a solid foundation for all music I play on my system, I still position my main speakers precisely, in relation to a single designated listening seat, to optimize the midrange, treble and sound stage imaging.  My main speakers only have a rated bass extension down to 35 Hz and I run them full range with the Debra set at slightly less than 50% with the crossover frequency set at 40 Hz.  This results in a seamless integration of the bass with my main speakers.  
    Even though the Debra subs and my main speakers are all outputting the fundamental bass tones below 80 Hz in mono that cannot be localized, I still perceive a full range stereo sound stage because the harmonics or overtones of these fundamental tones, which reach frequencies above 80 Hz and can be localized, are being reproduced in stereo by the main speakers. 
     The secret sauce is then provided by our brains, which are  capable of associating the bass harmonics or overtones above 80 Hz with their related fundamental bass tones below 80 Hz, and create the perceptions of where specifically the fundamental tones are coming from.  This whole process is seamless and results in our being able to perceive the deep bass drums being located at the rear center of the sound stage image, for example, and the upright bass being located at the front left side of the sound stage image.

mitch2:
" Based on my experience going from one sub to two, as well as what I have read about the subject, I would like to try adding a third SW12 placed asymmetrically in the room.  If I were starting over, I would definitely try Duke’s Swarm Subwoofer System but as @erik_squires points out, you need to be willing to have four additional boxes in your room."

     Yes, I know with certainty that a good quality multiple sub bass system can be created using as few as a pair of good quality subs, provided they're properly positioned/configured and good bass performance is only desired at a single designated listening position and not throughout the entire room.
     Three subs have also been proven to be sufficient, in some rooms, to  form a DBA that is virtually as effective as a 4-sub DBA and is claimed to provide good bass performance throughout the entire room, not just a single designated room location.  I
      recall reading this in the Earl Geddes article linked below:
   https://mehlau.net/audio/multisub_geddes/
     Mitch2, you also may be interested in one or more of these good quality wireless subs that have received good reviews:

https://www.underwoodhifi.com/products/syzygy-acoustics

atmasphere:
" In a nutshell this is an education thing and nothing more.

Those that denigrate a distributed bass array are apparently simply ignorant of its advantages. Many dealers don't sell them, so their comments can be sidelined safely enough.

If your front speakers actually make bass, then what you do is add a pair of subs elsewhere in the room to break up the standing waves that often cause bass cancellation at the listening chair."

     I agree, the whole 4-sub DBA  concept is not overly complicated but does require some education, self provided at online sites or at least read this book I'm currently writing.  I think a good understanding of the underlying principles as well as proper setup and configuration procedures should be sufficient.

teo
" Actually Eric is correct in the idea that it does not fix the room. This swarm idea. It overwhelms the problems and buries it under noise, in an area where the human ear is least sensitive. Like Styx said, "you’re fooling yourself if you don’t believe it..."

First, Fix the room."

      I believe teo_audio and Eric are correct that the swarm does not fix the room.  As I understand the swarm concept, the 4 subs actually create an abundance of more bass room modes throughout the room and uses a well known psychoacoustic principle, mainly that our brains process an abundance of bass room modes present in a room by summing and averaging these room bass modes by frequency, which results in our brains creating perceptions that the bass is smoother, faster and more detailed.     
     During the first four years of using the 4-subb Debra system in my system, I utilized zero room correction software or hardware and the only room treatments existing in the entire room was wall to wall carpeting and a few live house plants. 
     This wasn't because I disagreed with, or wasn't aware of, the importance or effectiveness of quality room treatments in attaining optimum full frequency range audio performance.  I did, but just hadn't gotten around to having my room professionally analyzed and treated.
     I've since had a full professional room analysis done by GIK, purchased several thousand dollars of a variety of their suggested room treatment products and have had them all installed about a year ago. 
    GIK's recommendations included floor to ceiling bass traps in all 4 corners of my room, 3-5 additional bass trap panels scattered about and and about 20 midrange/treble frequency range absorbing and diffusing panels at strategic locations along the perimeter 4 room walls. 
     My main point is that I was initially leery about so much bass trapping treatments because the 4-sub Debra DBA had worked so exceptionally well, with virtually no treatments at all in my room, for the previous 4 years that I was concerned the abundance of bass trapping might negatively effect the Debra's excellent bass performance.  
     After reassurances from GIK and Duke that the added room treatments would not negatively effect the bass performance of the Debra DBA, I had all the GIK recommended room treatments installed in my room, including all of the bass traps.  I anyone is curious, you can view the room treatments on my system pics.
     Overall Duke and GIK were correct, the Debra's bass performance remained exceptionally good. I noticed significant improvements in my system's midrange, treble and imaging performance, mainly a substantially lower noise floor, improved detail and an even more realistic, deeper, wider and 3 dimensional sound stage imaging.
   So to those stating to fix the room first for Pete's Sake!, my experience is that it minimally effected my room and system's bass performance but dramatically positively effected most everything else.  Definitely worth the dough overall, IMHO, but obviously not required for very good 4-sub DBA performance.
     Okay, sorry for the War & Peace length of this post but I prefer my books be thorough.

I hope this tome helped someone,
    Tim
@audiokinesis 
(Actually imo one sub may not always be better than no sub - many dipole owners have tried one sub and gone back to no sub.)
This thread and another also about sub woofers are really informative to myself. The advocates of multi sub array do make sense to me.

I already have a dual opposed firing single sub, I do like that the two drivers fire 180deg away from each other and cancel a lot of cabinet energies.
I have also an interest in slot loaded folded dipole design subs.

Have you heard or do you know of anyone who have combined a non ported sub with two or more dipole design subs? If I build one folded dipole, I am certainly doing two at the same time.




So to those stating to fix the room first for Pete’s Sake!, my experience is that it minimally effected my room and system’s bass performance but dramatically positively effected most everything else.
It seems i am deluded or in hallucinegic transe if you were right....

I fix my room and this had a tremendous effect on bass .... Clarity and quantity.... Your experience confirm my experience that PASSIVE only room treatment is insufficient... We need ACTIVE device controls also....

I re-mute myself....
mahgister Yeah, but did you have a swarm or an array of sub woofers?
If you did not, he was very specific in saying that he did, for many years, before applying room treatment. And it was in other areas he found the more significant performance increase with correct room treatment. The sub array had benefits all on it's own, would be my guess?

mahgister, do you have, or did you have a swarm or array of multiple subs?
If not, this does not directly apply to your personal experience, it's evident that what I have with my one sub isn't the even close to the array experiences shared here.
Have you heard or do you know of anyone who have combined a non ported sub with two or more dipole design subs? If I build one folded dipole, I am certainly doing two at the same time.

@rixthetrick, I currently use a DBA I set up with 8 sealed subs (I stack them in pairs) I made and am in the process of building the Linkwitz open baffle subs (W frame) but using a different set of drivers than the Seas that Linkwitz specifies. I will initially be subbing them in for two of the sealed subs and leaving the rest in place. We'll see how it goes.
clio09 - I am very interested in hearing more about your experience with this. Thank you.
mahgister Yeah, but did you have a swarm or an array of sub woofers?
You are right i dont have one..... Sometimes we must be silent....I let escape one occasion to be silent....

My best to you....
I hope this tome helped someone,

    Tim
Yes, helped me Tim. Thanks!
I'm at a point where I have the gear I want and I have setup my speakers to the best of my ability. Room treatment is my next project. I know you went the GIK route. Sounds like all went well. What do you think about Acousticfields vs GIK vs others? What made you go GIK?

what..no takers on bass beyond flat frequency response ?

seriously, download Vandertones ( its free ! ) get a analog RS SPL meter ( which you need to level matching anyway ) and at least see what your current room / speakers are doing.....
@mapman

That’s a nice collection of speakers you are rotating.

What determines which ones get played?

I have ls50s. Interested in your impressions versus others.

Thanks.

Other than having fun swapping around gear, nothing really determines which get listened to.

But the Harbeths are what I listen to most often.

However, impressions are easy to describe.

The LS50s are noticeably the best at imaging.
They project the smallest soundstage on their own but not far from the rest except for the B&Ws and especially the LRS.

The LRS is also more airy and enveloping.
Sounds a little faster than the LS50s.
Less accurate imaging.
These only have about 40 hours so may still be breaking in?

The Ologe5 is a different animal.
3 tweeter array in each main projects the widest sweet spot.
Non parallel cabinet walls.
More relaxed than the LS50s. Perhaps better for jazz/classical.
A little taller and wider soundstage.
Not nearly as accurate imaging as the LS50s.
Despite the two bigger drivers, the LS50s punched nearly as hard.

These are now being used as my left and right front HT mains in the living room.


The B&W 801 Matrix S2s just have this accuracy and flatness beyond my other speakers with the Harbeths being the possible exception.
But nothing I have can touch these when it comes to feeling the dynamics. The room really pressurizes with them.
Really big soundstage.

The LS50s sound much smaller and less neutral.


The Harbeths have greater extension above and below where the LS50s can go.
This is an extremely neutral speaker. Probably comes closest to the LS50s with accurate imaging.

Something about the sound though is just uniquely inviting.
Not sure how to describe it but the midrange in particular is intoxicating. The super tweeter makes it almost as open an airy as the LRS.
Overall much deeper and taller soundstage.
Probably one of the best balanced speakers I have ever owned.
Also, has the least coloration of any box speaker I have heard or owned.
The LS 50 comes close in this regard.

I also swap around a Hegel H190, Forte1A, Michael Yee Audio PA-1 and a Bryston BP26 controlling a pair of Ampzilla 2000 Second Edition monoblocks.

Note, the B&Ws really needed the 300wpc monoblocks to shine.
The Hegel was actually not far behind.

So can only provide impressions with the two amps.

The other 4 speakers were fine with any of the amps listed above.

The LS50s had the most performance gains with the DBA.
All that accurate imaging was presented in a taller, deeper, wider an fuller soundstage.

This is a really impressive speaker. With the DBA, it is pretty much holding it’s own enough to be in the regular rotation.

If you are considering any of these other speakers, I would be happy to provide more detailed info, listening impressions, etc.










rixthetrick:
" mahgister Yeah, but did you have a swarm or an array of sub woofers?
If you did not, he was very specific in saying that he did, for many years, before applying room treatment. And it was in other areas he found the more significant performance increase with correct room treatment. The sub array had benefits all on it's own, would be my guess?"

Hello rixthetrick,
     You are correct, my AK Debra DBA performed exceptionally well in my room and system, very close to identically from my perspective, whether there were virtually zero professional room bass trap treatments or a complete GIK recommended quantity of them in my room.  I was actually expecting and hoping for at least some slight improvements but failed to notice any.
     I should note for clarity that there were no before and after room analysis measurements taken of my room to verify there were no improvements in bass performance resulting from the addition of the multiple GIK bass traps.  My comments are based only on my personal and subjective perceptions.

Enjoy,
Tim
     
    
Your room is so close to mine-  within about a foot each way- and your DBA so similar to mine, we should have virtually the same high quality bass. Anyway, I can hardly imagine how bass traps would be an improvement.
Hello millercarbon,

      I bet our room bass qualities are very close.  I was so concerned the bass traps might detract from my DBA's bass quality, I was initially going to delete all the bass traps from GIK's plan for my room.  There was a lot of them and those GIK bass traps aren't cheap.  I know the DBA concept works perfectly with no bass traps at all and the absolute last thing I wanted to do is detract from its high quality bass in any way.  
      I believe anyone who's personally experienced the DBA's performance would feel the same way.  I've never really liked the idea of bass traps and these are the first I've ever used; they've never made much sense to me.  Your system produces bass and then the bass traps reduces it?  Huh?  It's always reminded me of running the AC with the windows open. 
      I know it's more complex than that, I probably just don't completely understand the acoustic dynamics at work and they could be the reason my system's performance from the midrange on up, along with sound stage imaging, has never sounded better.  I'm trusting some experts, GIK and Duke. they haven't steered me wrong yet and overall I'm very pleased with my GIK investment.

Later,
Tim
veerossi:
" I'm at a point where I have the gear I want and I have setup my speakers to the best of my ability. Room treatment is my next project. I know you went the GIK route. Sounds like all went well. What do you think about Acousticfields vs GIK vs others? What made you go GIK?"

Hello veerossi,
       I checked out the Acousticfields' website and their products seem to be of very high quality.  I think I considered them when I was looking for a room treatment vendor but thought they were a bit on the expensive side and I didn't know if the premium prices were justified.  I noticed they also offer a free room analysis just like GIK.
     I went with GIK mainly because a lot of members here seemed to like their performance, I liked their variety of treatments, especially the canvas art panels my wife really liked (which was important to me since it's her living room, too.) and they seemed like high quality treatments at reasonable prices.  I knew good quality treatments wouldn't be cheap but I wasn't looking to get fleeced, either. 
     Overall, I'm very pleased with the performance, fit and finish, customer service and total costs of the GIK products.  I'm not certain but I suspect the Acousticfields treatments are a step above the GIK in quality but also in price.  
     I'd suggest you take advantage of getting a free analysis from both companies, which will include a list of recommended products along with a total price quote, which will probably help with your decision.  This process also provides info on their customer service quality levels and differences along with the interesting and fun of comparing 2 complete and independent plans and strategies for your room.

Best wishes,
    Tim
So I think most people would agree that addressing excess decay times (ringing) is as important or more important that flat frequency response.  I've added a good bit of range limited traps to my room which have helped substantially to reduce ringing.  Overall, the room is about 20% treated with the vast majority being range limited bass traps (GIK Soffit/Mega and Realtraps Mondo limp membranes) in the corners and front wall.

For those of you using DBA combined with room treatments, did you find that the DBA reduced ringing substantially without room treatments, or should I expect my Swarm to primarily rectify nulls at the MLP and expect that the traps will be required to achieve good decay times?

I guess my plan would be to remove room treatments and optimize the bass response without room treatment, then add back the bass traps judiciously to further improve frequency response and ringing.  BTW, mains are down 3 dB at 27 Hz, but I have decent response down to 20Hz or so.  Is that a reasonable approach?

Finally, I've read about the crawl approach to optimal placement on the Audiokinesis site, but I'm thinking of using REW to supplement what I hear.  Anyone find REW useful in Swarm sub placement?


@tyray
 Then reading more in agon Duke did suggest to the things he told you to do with your subs, then I can't remember if it was Duke on some other reading but 'if you can raise one up towards the ceiling'. What!

Yes, that was Duke who suggested raising one or more subs up towards the ceiling here on agon.

I had decided against the Swarm for my 10 x 12 room until I read the same posting.

It was in that small room that I used a metal shelving unit in each front corner to place a ceiling facing sub with about 4" clearance.

A third ceiling facing sub was mounted on a shelf above and behind my listening chair.

After minimal placement adjustments, I had really great bass response in the small room.

No other single sub worked.  I was literally in a state of awe and shock at how the 4 subs significantly improved my listening experience across different kinds of music at most any volume.

Now in the new house, with a bigger listening room (14 x 17) I have 2 subs on the floor but still have 2 up high facing the ceiling.

I agree with you about being glad you actually tried and elevated a sub.  It really does work!

The ceiling facing subs do noticeably contribute to the vertical plane dispersion. The shelf units in each front corner provide some diffusion and are great for housing gear too!

I have a monoblock at the bottom of each shelf unit which helped streamline the crowded gear rack between my mains.


Mahgister wrote:

"With acoustic ACTIVE devices controls and not only PASSIVE materials treatment, they gives me so much bass..."

"You forget Active acoustical device controls..."

"For example how do we use reverberations in a positive way to make the sound more alive with only a passive treatment? No way, it takes active acoustical control devices..."

"Active acoustic devices controls seems totally unknown"

"The easiest low cost way to improve bass is to improve the acoustical settings controls of the room not only passively but actively..."

You mention ACTIVE acoustical control devices many times, in this thread and elsewhere, and I don’t know what you are referring to.

Can you describe or explain what they are?

Duke
Active devices controls of the room with a balance between, absorption, reflections, and diffusions, and using device (different diffusors of my creation and active resonators connected to a grid of low cost Schumann generators) to take the positive side of reverberations for example....

Active because i connect them to the S.G..... And the different resonators of different size .... I use my audio room only for music then it is possible to experiment....In a common room my device are not esthetical nor practical....

But i think it is not the thread to describe these unorthodox experiments of mine...My only point is treating the room must be made for all frequencies and in relation to timbre accuracy first and not bass....

:)

 I apologize for having disrupted this thread.....

My best to all....
@mahgister,

Why not start a thread with a detailed explanation of your three infamous embeddings? I think it’s long overdue :-)
Thank you mahgister.

What do you mean by "active resonators"? Are these Helmholtz resonators, and/or do they have moving parts? Do they operate in the audible band? 

Duke
I called them active because they resonate in diffusing the sound....They are also many of them connected to my Shumann generators.... I use also Helmholtz resonators....But the resonators i use most were cheap brass cap or cone of different size in some grids...Connected or not... With some minerals in the center or not..... My diffusors plays a great role also... I use a grid of "strings of cheap minerals" suspended from the ceilings, some are connected some not.....Very efficient to diffuse the sound.... The main problem was for me the balance between reflective, absorbent and diffusive surface or device...

They are certainly audible because i only use my ears.... :)

I take many months to create this room.... And there is no comparison at all in nearfield or regular position with before and after....

It is why acoustic control for me exceed often upgrading electronic component in powerful transformation of S.Q.