Small or large sub for music

" 2. One Sub- With a single sub, unfortunately, the bass will be compromised because the bass will only be optimized at a single point in your room (your listening seat sweet spot) and the bass will not sound as good at other spots in your room. To optimally position a single sub, place the connected sub at your listening position/seat and play some content that contains several minutes of good and repetitive bass. Then, starting at the front-right-corner of your room, slowly walk counter-clockwise along the walls of your room until you find the exact spot where the bass sounds best to you. Lastly, locate the sub to this exact spot and then replay the bass content to verify the bass still sounds good to you when your seated at your listening position/seat.
     mcreyn, Isuggest you may want to try this in your single sub office system."

Already did this.  The sub started on the front wall, then the corner, and ultimately at the midpoint on the rear wall.  Response from it is great there, and decay times are good.  Since I am sitting at a desk, my listing position is always within a few inches making tuning easier as I only have to cope with one position.  

The big issue I have is not sub related.  I have a huge mode at 140 hz, followed by a suckout at 110 hz (and smaller ones at 65hz and 55hz).  I am waiting to hear back from GIK acoustics, but will be trying some 244 bass traps to see if I can moderate this.  Corner traps are not an option, but the 244 absorbs 16 sabins at these frequencies so should work well.  

Hello mcreyn,

     I'm generally against the use of bass traps and other room treatments that attempt to improve in-room bass response.  I much prefer reducing or eliminating the root cause of poor bass response in most rooms, the existence of bass standing sound waves that cause bass exaggeration, bass attenuation and even bass disappearance. at various specific room spots.
     I tend to view bass room treatments as misguided, similar to using air conditioners at specific spots to reduce the heat in a room that gets too hot on cold  days.  Just as a lack of room air circulation is often the root cause of poor room temperature control, a lack of room bass sound waves circulation is often the root cause of poor room bass control.

     As I've stated ad nauseam previously, deploying  a 4 sub distributed bass array system is the only guaranteed method I've yet discovered that provides sota bass response in virtually any room. 

     I also understand why you may not want to devote the funds and space required in your rather modest office system.  If this is the case, the best remedies I can think of for your bass peak and nulls in order of cost and room space are:

1.  Start from scratch and re-perform the procedure for locating your sub in a single sub system.  I know nothing about your actual office room, but I'm thinking  there's likely a better performing specific spot for your sub than its current position.  As you walk around your room searching for this spot. you may want to also check spots that are not solely along your walls.  Moving your sub even a few feet away from the wall could improve bass response at your listening position.

2.  If this is unsuccessful, my best advice is to consider using a second sub.  The use of 2 subs, if properly positioned, is the first remedy that will begin to reduce or eliminate some room bass standing waves that are the root cause of your room's bass issues.

3. Addiing 2 subs will further this attack on bass standing waves and improve bass response.

4. Add 3 subs and you'll attain sota bass performance not only at your listening seat but throughout your entire room.  The additional subs suggested in any of these remedies are not required to be of the same type, or even the same size or quality, as your existing sub.  The critical factor is that having 4 points launching bass sound waves into any room is scientifically verified to reduce or eliminate the vast majority of bass standing waves and will likely provide the best bass response you've lever heard.

Hope this helped a bit,
        Tim

Tim,

We are going to have to disagree.  The issue I have with my office is not a subwoofer issue, it is centered at 140hz, at which point a sub would be down over 20db assuming a normal 24db/octave low pass at 80hz.  It doesn't matter whether I am using 1,2, 3 or 4 subs, the huge mode I have is way outside of that range. 

In my office, I have 3 potential spots to put a single subwoofer.  I have measured all of them carefully and done the crawl, this is the best position of my choices. 

As far as room treatments, I believe that most rooms can benefit from them.  The speakers and their interaction with the room are by far the largest determining factor in sound.  I do believe in optimizing placement as a first step, but then what?  Most rooms have long decay times and the first reflection points are too close, causing image smearing and brightness.  $500-1000 in room treatments can transform how a system sounds.  There is very solid science behind the reasons for and how to treat a room.  You might find this article interesting:

http://www.gikacoustics.com/room-setup-case-study/

Finally, I think DSP is a great idea when placement and room treatments have not worked.  I see the three all working together as a system.  

sleepwalker65 wrote:

Subwoofers are a bad solution for inadequate speakers. They are mutually exclusive with high fidelity because they can never perfectly integrate. Some people and rappers don’t care about sound quality. Low-Fi is fine for them. For the rest of us, subwoofers only belong in the home theatre.

I guess it depends on what you mean by the term inadequate.  After 45 years of audio and hundreds of speakers (I used to be an  audio dealer and distributor) I have come to the conclusion that, for most rooms and most speaker designs, the concept of a "perfect" full range speaker is very hard to achieve; bordering on the impossible.

These days I play almost exclusively through tube components, SET and low output PP.  I have extensively tested many high efficiency, single driver speakers and find that, to my ears, limiting the driver size to 8" or smaller and mating to a pair of good sealed subs gives my more audio joy and sense of performance realism than the (many pairs) pf much more expensive "full range" speakers I have played and owned in the past.

It's true: getting the best sound out of a pair of standmount speakers and separate subs isn't easy.  It's a lot of work to get it just right.  But IMO it's worth it.

mcreyn:

" As far as room treatments, I believe that most rooms can benefit from them. The speakers and their interaction with the room are by far the largest determining factor in sound. I do believe in optimizing placement as a first step, but then what? Most rooms have long decay times and the first reflection points are too close, causing image smearing and brightness. $500-1000 in room treatments can transform how a system sounds. There is very solid science behind the reasons for and how to treat a room. You might find this article interesting:

http://www.gikacoustics.com/room-setup-case-study/

Finally, I think DSP is a great idea when placement and room treatments have not worked. I see the three all working together as a system."

     Perhaps I wasn't clear but my comments were concerning the use of room treatments for optimizing in-room bass response, not midrange and treble response,  and their general futility. 
     I've come to the conclusion that it's best to treat my system as 2 systems: a bass system and a midrange/treble/sound stage illusion system.  The 4 sub dba gets the bass sounding powerful, accurate and defined throughout my entire room without the need for any dsp,  equalization or bass room treatments.  It creates a solid foundation for all music and is excellent for ht.
     The final step is positioning the main speakers to optimize the midrange. treble and sound stage illusion at the listening position sweet spot (unfortunately, there's currently no known method of optimizing this response throughout the entire room  as currently exists for bass response. via the 4 sub dba.)  I completely agree with you that there are very necessary and beneficial methods, backed by solid science, of employing room treatments for optimizing the in-room midrange and treble response along with optimizing the sound stage illusion/imaging at the designated listening position.
Tim

mceryn:
Finally, I think DSP is a great idea when placement and room treatments have not worked. I see the three all working together as a system.

Proper positioning of my subwoofers and their onboard customizable Room Optimization has always improved their performance. I've never been satisfied with low frequency room treatments. A mater of taste and probably just lucky with my last three rooms.

I have a “full” range speakers supported by 2 JL212 subs. The subs Integrated with the main speakers so well that now I cannot listen to the system without the subs. The quality of the subs is very critical.

I would disagree and say that getting the phase, crossover, sub volume, and room modes taken care of are more important than a high quality sub.

A few well integrated Dayton subs can outperform a hifi subwoofer that is much higher quality.

One of the reasons some hifi folks hate subwoofers is because you can’t just spend more to get better bass. Ironically more expensive subs can just amplify problems with the room and setup since they are so powerful.

Iseanheis 1: "I would disagree and say that getting the phase, crossover, sub volume, and room modes taken care of are more important than a high quality sub.""

     I agree and would suggest getting the room modes taken care of (significantly reduced or eliminated) is a good place to start.  In my experience, this is relatively easy to do with 4 subs but more difficult to do with just 2 subs.  With 2 subs, the goal needs to be lowered to taking care of room modes solely at the listening position, which is acceptable for many systems.
     I believe many are under the false impression that if you just use 2 high quality/expensive subs and place them in convenient positions it will result in good bass response.  I would caution that this approach will likely provide plenty of bass but whether one would perceive this as 'good bass' is much less likely.  I can state with certainty that utilizing 4 properly positioned subs, even if they are of lower quality and size, will result in more accurate bass that is better integrated along with the capacity for impressive bass power as well as the agility to keep pace with the fastest main speakers that never produces bass that lags behind or seems disconnected.
     I consider getting the crossover frequency, volume and phase set correctly as final fine tuning steps to attain a desired in-room bass response standard or preference.
     I just want to stress that attaining state of the art bass response via a properly setup distributed bass array system is not a matter of opinion.  It is a scientifically proven method that works incredibly well in virtually any room.  It just happens to have the added benefits of not requiring the highest quality subs, having the option of being bought as a complete kit or custom assembled and being affordable.
    I'm also certain that most, if not all, readers who audition a dba would recognize its obvious excellence quickly in their or really any system.
 Tim
     

Without prejudice to all the good comments highlighting the warts introduced by poor room acoustics, It’s not about size of the sub but rather the quality of build of a sub that has a large determinate in how it sounds to you.

There are good ones out there including ATC and the Vandy highlighted herein and others. Their common element is quality build .

here is a repost .... The following article has been posted before and is rehashed again below - one of the finer reads in the subwoofer selection tree .... best article I’ve seen discussing subwoofers for non-HT applications.

August 3, 2008

http://ultrafi.com/why-everybody-needs- ... subwoofer/

"…And Why a Really Good Subwoofer is so Hard to Find

Audiophiles and music lovers are missing out on one of the most dramatic improvements they can make to their audio system: Powered Subwoofers.

Most audiophiles won’t even use the word “subwoofer” in public, let alone plug one in to their precious systems. There is a kind of snobbery that exists in the world of high-end audio aimed primarily at receivers, car audio, home theater and especially subwoofers. As a matter of fact, subwoofers are responsible for many people disliking both car audio and home theater, since it is the subwoofer in both of those situations that tends to call attention to the system and cause many of the problems.

The truth of the matter is that subwoofers have fully earned their bad reputation. They usually suck. Most of them sound boomy, muddy and out of control with an obnoxious bass overhang that lingers so long as to blur most of the musical information up until the next bass note is struck.

We have all had our fair share of bad subwoofer experiences, whether it’s from a nearby car thumping so loud that it appears to be bouncing up off the road, or a home theater with such overblown bass that it causes you to feel nauseous half-way through the movie. You would think that high-end audio manufacturers would be above all of that, but you would be wrong. In many cases, their subwoofers are almost as bad as the mass-market models because they too, are trying to capitalize on the home theater trend that is sweeping the land.

You see, it’s very difficult and expensive to build a good subwoofer. One reason is that a sub has to move a tremendous amount of air, which places big demands on the driver (or drivers). Moving lots of air requires a lot of power and that means an amp with a huge power supply, which can cost huge money.

Finally, in trying to move all of this air, the driver (or drivers) which operate in an enclosure, create tremendous pressure inside of the box itself. The cabinet walls must be able to handle this pressure without flexing or resonating. Building such a box involves heavy damping and bracing which gets very expensive. When you consider these requirements, you quickly realize that it is virtually impossible to build a really good subwoofer (I mean good enough for a high-end music system) for under $1000. Yet most of the subwoofers out there sell for between $500 and $900. Manufacturers do this because their marketing research has shown them that that is what people want to spend on a sub, never mind the fact that what people want to spend and what it takes to get the job done right may be two different things. The result is that even most high-end manufacturers are putting out poorly constructed subwoofers that just don’t sound very good.

I don’t want to give you the impression that anyone who really wants to can build a good subwoofer so long as they are willing to throw enough money at the problem, because that really isn’t true either. There are some pretty expensive and well-constructed subwoofers out there that you would never want to plug into your music system because they would most certainly make the sound worse.

Why? Because of their crossovers.

A crossover is inserted into your signal path in order to remove the lowest frequencies (the deep bass) from your main speakers so that they no longer have to do all of the dirty work. The deep bass will instead be dealt with by the subwoofer.

The #1 benefit of adding a high quality subwoofer to your system is not how it further extends the bass response, but how it can dramatically improve the sound of your existing power amp and main speakers from the midrange on up. That, my friends, is by far the most compelling reason to add a sub to your high-end music system. Once your main speakers are freed from the burden of making deep bass, they will sound cleaner, faster and clearer, especially in the midrange and midbass.

They will also image way better because there will be far less air pressure and therefore resonance and vibration affecting their cabinet walls.

And since the power required to make the deep bass is provided by the subwoofer’s built-in amplifier, your main power amp will be free from that burden and begin to sound like a much more powerful amplifier.

The one big problem with all of this is that you need a crossover to roll off the deep bass in your system and achieve all of these benefits. And the crossover that comes with almost every subwoofer on the market will cause more damage to your signal than can be overcome by these benefits. That is the main reason that audiophiles refuse to consider adding subwoofers, even very expensive ones with well built cabinets.

Enter the Vandersteen 2Wq 300 watt powered subwoofer. This is the only subwoofer that is specifically designed to be inserted into the highest of high-end music systems without doing any harm to the precious signal.

So how does Vandersteen do it?

Simply. In fact his crossover scheme is so ingeniously simple that it’s a wonder nobody else thought of doing it the same way. I’ll spare you an in-depth description and just say that the only thing you end up inserting into your system is a couple of high quality capacitors. That’s it, nothing more!

No additional wires or gadgets enter your signal path. Hell, you don’t even have to disconnect the wire between your amp and speakers to add this subwoofer. The model 2Wq sub uses the same basic crossover scheme as the $15,000 flagship Model 5As. As a matter of fact, you can even run the specially designed Model 5A crossovers (M5-HP) with the 2Wq if you want the most transparent sound imaginable.

So what about the other reason to add a subwoofer to your system: for more powerful and extended bass? I don’t care how big your main speakers are, they’re no match for a good subwoofer in the bass.

A really good subwoofer can run rings around the best floorstanding speakers when it comes to bass extension, power and control because it is designed to be good at that and nothing but that, whereas main speakers have to be good at higher frequencies as well. Ideally, you want two subwoofers so that you have true stereo separation down deep into the bass. Stereo subs can also help to lessen room interaction problems by providing two discrete sources of bass information. Remember, if you can’t afford to buy two subwoofers at once, you can always add the second one later. Adding a pair of 300 watt powered subwoofers is exactly like adding a pair of 300 watt monoblock amplifiers to your system and upgrading to a pair of better main speakers at the same time. The beauty is that you don’t have to replace your main power amp or speakers to do it.

But there is a problem here as well.

Everything comes at a price, and the price you pay with most subwoofers is that when you add them and their built-in amplifiers to your system, they don’t tend to blend or integrate well with the sound of your power amp and speakers. This is especially true if you own a tube amp, because the character of your amp is nothing like the character of the big solid-state amp that is built into most subwoofers.

The result is that your system sounds split in half. You can hear where one part of the system leaves off (namely your amp and speakers) and where the other part takes over (the sub and its amp). This is a HUGE problem for audiophiles who aren’t willing to destroy their system’s coherence for additional power and bass extension.

Fortunately, Vandersteen has the perfect solution for this problem that is, again, so simple, I wonder why nobody else thought of it first. His solution is to build a very powerful 300 watt amplifier that strictly provides the huge current needed to drive the subwoofer. You can think of this amplifier as only half of an amplifier; or just the power portion of an amplifier. The release of this power is controlled by the signal that is provided by your power amp. Vandersteen’s amplifier needs a voltage to modulate its current output, and what better place to get that voltage than from your main power amp? This way, your power amplifier is directly responsible for the sonic character of the deep bass coming from the subwoofer because it provides the necessary voltage signal. This voltage signal contains the unique and characteristic sound of your main power amplifier and insures that that character is maintained in the sound of the subwoofer itself. The beauty of it is that your amplifier is only providing a voltage reference and no actual current, so it is not taxed with the burden of “driving” the subwoofer in any way. As a matter of fact, your amplifier doesn’t even know that the sub is connected to it. The 2Wq’s potential is almost unlimited given that it will ratchet up its performance as you improve your power amp. Remember that you always want your subwoofer to sound just like your power amp. No better, no worse. NO DIFFERENT!

After having spent time with the amazing Vandersteen Model 5A loudspeakers with their 400-watt powered, metal cone subwoofers, we were reminded of the sound we had with the awesome Audio Research Reference 600 mono power amps. With the Ref 600s there was a sense of effortlessness, openness and unrestricted dynamic freedom that we have only otherwise heard with live unamplified music.

Listening to those monstrously powerful amps made us realize that all other systems sound compressed by comparison. Only when we heard the new Vandersteen Model 5As with their hugely powerful built-in subwoofers, did we again have a strikingly similar sonic experience. The reason is that the Model 5As provide a total of 800 high-quality watts, to which you have to remember to add the power of the amp we were using, the ARC VT-100, at 200 watts.

This means we were listening to about 1000 total watts of amplifier power – not far from the 1200 total watts provided by the Ref 600s. With the Vandersteen subwoofer crossover and amplifier, you are able to get those hundreds of subwoofer watts to blend seamlessly and even take on the character of the ARC VT-100. It’s amazing! What’s even better is that the price of the system with the Model 5As and the VT-100 is under half the cost of the Ref 600s alone! Since this discovery, we have achieved the same kind of unbelievable dynamics and seamless blending with ProAc loudspeakers and twin Vandersteen 2Wq 300 watt powered subs.

So, if you want the sound of Ref 600s but cannot afford them, buy a pair of Model 5As or your favorite pair of ProAcs plus a couple of 2Wq subwoofers and mate them with a VT100 and you’ll get surprisingly close.

You can cut the cost even further by running a pair of Vandersteen 2Wq 300-watt subwoofers with your existing speakers.

Or mate a pair of 2Wqs with your favorite ProAc. In any case, it is the magic of SUBWOOFERS that allows this to happen.

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.

And the Vandersteen 2Wq is the one. And just in case you think I am a biased source, our correspondent Blaine Peck (who, for all you know is also a biased source) recently wrote the following, with no discussion between us about the topic prior to his sending us his comments.

Whether reproducing the plucked string of an acoustic bass or the sound of an analog synthesizer, the Vandersteen 2Wq subwoofer is a seamless extension of any system. Nothing else need be added! With its internal 300-watt power amplifier, it is the perfect compliment to any sound system. Designed to take on the characteristics of your main stereo amplifier, the amp in the 2Wq will not sound foreign in your system. Also, through an extension of the Vandersteen design philosophy, a unique gradually sloping crossover system is implemented so you simply do not know where your main speakers stop and the 2Wq begins.

Now that your main speaker/amplifier combination need not concern themselves with those power demanding low frequencies, they are freed up to work in a more comfortable range. Yes, now what is coming from your main speakers will sound better than ever.

The 2Wq is not just another subwoofer. It consists of three 8″ floor-facing drivers, each with a massive motor. So why not a more typical single 12″ or 15″ design? Well frankly, the mass of a larger driver will not allow it to respond as quickly as the Vandersteen 8″ drivers to today’s demanding recordings. The 2Wq’s 8″ drivers are designed to handle the content but be “fleet of foot” at the same time. Concerned about where to put them? You need not worry. With the control of both its respective level and the “q” (how loose or tight the low end is) you have the flexibility to place them in a location that fits your living environment and not sacrifice performance. The simple beauty of this product will soon become an addition to your room.

So whether on orchestral music, hard rock or something in between, the Vandersteen 2Wq will exceed your expectations...."

Hello akg_ca,

     No matter how high quality or expensive the subs utilized, having just 2 subs in any given room/system is incapable of producing sota bass response throughout the entire room.  The optimum potential is good bass reproduction at a single 'sweet spot'.  
     Is there a recommended positioning method that Vandersteen or you provide to customers?
Thanks,
   Tim

Room size and low frequency extension desired determines how large a sub need be. In general you need a larger sub with a larger bass driver or possibly somewhat smaller if multiple drivers or passive radiators are used if your room is larger and you want bass to extend all the way down to 20 hz or so which is typically about as low as any music like low pipe organ notes might go.

So basically size does matter when it comes to extended bass.  

For example I use a 8" sub with dual pasive radiators that can go down to almost 30 hz or so in a modest sized room.   I use these with small monitors somewhat similar in size to kef ls50  that do little below 60hz or so.    I don't know of any any single driver 8" sub that can do that.    

If your mains are larger and more full range you will likely have to go with a larger 12" or even larger sub iin order to cover the lowest frequencies not covered otherwise by the mains.  

Hello mapman,

     Sorry, I'm a bit confused by your last post. 
     As I understand it and in other words, you're stating that deep bass extension down to about 20 Hz can be achieved in most larger rooms through either a single large sub with a large driver or through multiple subs each with smaller drivers.possibly also incorporating passive radiators.  And you add that you're unaware of any single 8" driver sub that can reproduce deep bass down to the typical audible limit of 20  Hz.
     If the above accurately reflects your thoughts, I agree with you.

     But then you go on to state: 
" If your mains are larger and more full range you will likely have to go with a larger 12" or even larger sub in order to cover the lowest frequencies not covered otherwise by the mains."

      I think I clearly understand your statement but disagree with it. 
      I believe, in your quoted example above, that excellent in-room bass response down to 20 Hz +/- 3 dB can be achieved  in virtually any sized room through the use of 4 smaller subs with 10" drivers if configured as a distributed bass array system.  
     I believe this because my mains are larger and are run full range but only extend down to about 34 Hz.  I utilize a db, consisting of 4 smaller subs with 10" drivers, in my medium sized? (23 x 16 foot) room to provide excellent in-room bass response from 20-40 Hz  +/- 3 dB that integrate seamlessly with my large Magnepan panel mains for both music and ht.
     I understand you don't currently require this degree of bass extension in your own system but thought you'd like to know this type of bass extension is possible in virtually any sized room without the need for subs with 12" or larger drivers .

Tim        

TBC, having the space and money to have 4 subs is not the normal music lover's situation. 

@mapman  was talking to that. He was not discrediting the use of 4 subs. 

I too will never be able to have more than 1 sub in my listening area so to me, the 4 sub array point is moot.

That doesn't mean I don't see the merits. From a cost/performance space situation, the bass traps + eq are the far better and cheaper option, but hey, I make my own loudspeakers so the measurement and calibration is waaay easier for me than the average music lover. 

noble yes for 20 hz in large room you need at least 1 larger sub up to teh task (check specs) or multiple subs or drivers. Distributed multiple subs or sub array allows more  for smoother bass response throughout a room than extending low end frequency response..

Ideally I would want  2-4 larger quality subs distributed around a room but practically I do not want to have to deal with all that so I go with just a single smaller sub that is easier to manage.   This is in a second system.  My main system has full range speakers so no subs needed. 

Why does anybody care if the bass is distributed evenly around the room? Is this so you can enjoy accurate bass while doing your yoga headstand against the wall? Weeping about things in the corner until the housekeeper finds you? I use 2 subs that seem to help cancel some room standing wave issues, but I do serious listening from my specific sweet spot (like most audio geeks) which is where stereo mixes actually work. If anybody wants to really appreciate my rig along with me, it's necessary they sit in my lap or stand behind me while I sit in my "magic" spot. Also, it's possible to get great (and musically rewarding) sound from one sub as this is generally better than no sub at all. Movie sound is the McDonalds of audio...lots of salt and fat to make you feel good initially, but it has very little to do with good food...as a reference for audio, film sound is a ridiculous mix of extremes that isn't really designed for music appreciation. If you spend your time listening to and enjoying the digital reproduction of Army tanks and explosions, you're unique and hat's off to you!

I hardly ever sit in the sweet spot. and I have never been concerned with getting the deepest bass. I can't think of any of my guests wanting to stack up on or behind the sweet spot either, but we all want to hear good sound wherever we are in the room, or house for that matter. Not to mention I disliked having my guests ask me about all the acoustic panels I had and why. They appreciate my art collection that hangs on the wall now much more. Thanks to the 4 box distributed array we can eat, drink and enjoy music. Room size is 14 x 20 so with their small footprint they fit quite nicely and nobody trips over them.

erik_squires:
" TBC, having the space and money to have 4 subs is not the normal music lover's situation."

erik,
     Understood.  I consider myself fortunate that I was able to accommodate the relatively small 4 Debra subs in my room without issue and inconspicuously.  As for the money, I don't have an abundance but I could afford $3K and consider it a bargain.

erik_squires:
"@mapman  was talking to that. He was not discrediting the use of 4 subs."
mapman:
" noble yes for 20 hz in large room you need at least 1 larger sub up to the task (check specs) or multiple subs or drivers. Distributed multiple subs or sub array allows more for smoother bass response throughout a room than extending low end frequency response." 

erik and mapman,
     Yes, I didn't think mapman was discrediting the use of 4 subs, either.  I just wasn't sure if he knew that the Debra/Swarm dbas are capable of reproducing deep bass down to 20 Hz +/- 3 dB in any sized room (running in mono and in combination) and that 'at least 1 larger sub up to the task' is not required to reproduce bass this deep even in a large room.

wolf_garcia:
" Why does anybody care if the bass is distributed evenly around the room? Is this so you can enjoy accurate bass while doing your yoga headstand against the wall?"

wolf,
     I find it disturbing that you're aware I enjoy accurate bass while I'm doing my yoga headstands against my wall.  
    As to why I care if the bass is distributed evenly around the room, see clio09's post and my reply below:


clio09:
" I hardly ever sit in the sweet spot. and I have never been concerned with getting the deepest bass. I can't think of any of my guests wanting to stack up on or behind the sweet spot either, but we all want to hear good sound wherever we are in the room, or house for that matter. Not to mention I disliked having my guests ask me about all the acoustic panels I had and why. They appreciate my art collection that hangs on the wall now much more. Thanks to the 4 box distributed array we can eat, drink and enjoy music. Room size is 14 x 20 so with their small footprint they fit quite nicely and nobody trips over them."

clio and wolf,
     I agree with clio, my guests and I all want to hear good sound wherever we are in my room.  There is just one 'sweet spot' seat in my room for best overall performance but I and my guests think music still sounds good throughout the entire room because it's full range everywhere, from as deepest bass to highest treble as the musical content possesses.  Yes, the very realistic, solid and stable sound stage illusion existing only at the 'sweet spot' seat is missing.  But the overall sound of well recorded music reproduced in high quality utilizing the actual complete audible range can still be enjoyed throughout the entire room, even when seated at a table in the adjoining dining room. 
      My wife, guests and I also enjoy the evenly distributed sota bass response for ht.  Our room has 6 seats with good views of a 65" plasma hdtv.  The 4 sub Debra dba is part of a 5.4 DD surround sound system that, along with the large hdtv, allows for very good A/V reproduction experiences to be enjoyed at each of these 6 seats.  I realize this ht capacity is not relevant to some of you but it is to me, my wife, guests and likely some readers of this thread.

Thanks,
  Tim

Is this so you can enjoy accurate bass while doing your yoga
headstand against the wall?

I don't need a wall for that.

Size and # drivers (including passive radiators) is often a general indicator of how low a sub might go but you really have to check the specs to get a good idea how a sub will perform

Also lower bass frequencies take exponentially more power to produce flat response so you better have plenty of good clean amp power in those subs too to carry the load. The more the better. Not enough power in reserve is perhaps the most common cause of bad sounding bass.

It depends on the power available and the efficiency of the subwoofer. And of course the capability of the subwoofer, Bass frequencies do not inherently require more power than any other frequencies. Other factors can be involved such as absorption of frequencies in a given room, standing waves, etc.

     As I've stated previously, I was originally very skeptical about the DEBRA dba system.  The $3K price, having the space in my room to locate 4 subs in my 23 x 16 foot room without issues, would the system  actually work as advertised and would it disturb my system's already very good sound stage illusion (that I really enjoyed) were all important concerns I had.
     I justified the price as about the same amount I was already going to spend on my original bass improvement plan of buying 2 conventional self-amplified Vandersteen, JL or REL subs and positioning them to optimize the bass response at my listening seat.
     The room space concern I resolved by just committing to rearranging my living/listening room furniture and system if required for the sake of good bass response throughout my entire room.  Fortunately, after completing the progressive sub setup procedure I discovered this was no longer an issue.  Subs #1 and #2 sounded best positioned along my front 16' wall with each hidden from view by a 6'h x2'w mains speaker panel.  Subs #3 and #4 sounded best positioned with one along each 23' side wall.  Both are out of the way  and partially hidden from view, one by a large end table and the other by a large reclining leather chair.  
      My concern about whether the DEBRA dba system would provide sota bass response as advertised was lessened gradually. It began to be reduced as I began researching and learning online about the theory behind dba systems, experimental results and practical applications. 
     White Papers (summaries of their research) I read authored by leading dba researchers Dr. Earl Geddes and Dr. Floyd O'Toole, along with email and phone discussions with James Romeyn of Audio Kinesis, continued to increase my confidence in dba systems and alleviate my concerns .
     The 30-day free in-home trial period offered by Audio Kinesis  on the DEBRA system overcame my final concern about whether the mono dba would negatively affect my system's already very good sound stage illusion so I decided to purchase the DEBRA.  Ultimately, the sota bass of the DEBRA, even though it's the combined outputted sound of 4 separate mono subs, integrated precisely and seamlessly. I perceived the bass as originating from all the proper bass instruments and singers within my still very good sound stage illusion. 
     As I understand it, the extremely accurate, defined, natural and dynamic sounding bass reproduced by the DEBRA dba subs are all operating in mono, partially being reproduced from 4 separate subs located at different directions and distances from my 'sweet spot' listening seat (sub#1 along the front 16' wall about 3' in from the right 23' wall and about 18' away from my seat, sub#2 along the front 16' wall about 3' in from the left 23' wall and about 18' away from my seat, sub#3 along my left 23' side wall about 3' in from the rear 16' wall and about 8' away from my seat and sub#4 along my right 23' side wall about 3' in from the rear 16' wall and about 8' away from my seat.) and with each launching long bass sound waves that are all deep enough in frequency response that they should not be able to be perceived by myself as directional.  

     So how am I able to perceive these long bass sound waves as emanating from the proper physical locations within the very stable and solid sound stage illusion seemingly spread across the front of my 16' front wall (with the width, depth and specific locations of the lllusionary musicians and instruments varying with this sound stage illusion depending on the recording) if these bass sound waves are truly non-directional?

      I believe the answer lies in the fact that all recorded deep bass sound is comprised not only of the fundamental notes that are physically represented by low frequency sound waves that are non-directional but also of the deep bass note's harmonic notes that are physically represented by higher frequency sound waves that are directional.  
      It is these higher frequency bass note harmonics, high enough in frequency that they are reproduced by my system's main l+r speakers and not by any of the 4 subs that are typically restricted by the crossover setting to reproducing those that are 40 Hz and below, that actually allows the brain to determine where the fundamental bass note is emanating from.
     Well, I hope my words were adequate in communicating this rather complex concept. 
     If not, please let me know if you need me to clarify anything.
     If so, please let me know your thoughts on this concept.

     I definitely don't consider myself an expert on in-home bass systems.  I'm just a music and ht enthusiast who's always enjoyed the realism provided in both by very good bass response and I've been searching for a method to attain this in my system for decades. 
     I believe I've  discovered  a concept, the distributed bass array system, and a couple of complete dba kit products , the Audio Kinesis Swarm and DEBRA  4 sub dbas, that I'm thrilled with because the DEBRA  system I bought and installed has finally provided what I consider sota bass response to my system for both music and ht.   
     I now feel an obligation to spread the word on this high performance bass system solution on this high performance audio/video internet discussion forum site.  I have no connections to Audio Kinesis besides being a very satisfied customer.

Thanks,
   Tim

Bass frequencies absolutely require MUCH more power than treble or mids, to state otherwise is ridiculous.

Why, it’s almost like you didn’t go to school. Oh, I almost forgot. You didn’t.

I've been in the actual music biz for over 5 decades...back when we used Altec A7s (extremely efficient) we typically ran maybe 200 watts into the bass speakers and 50 to 100 into the horns to make things balanced. Now I use 1500 watt powered bass systems, with maybe 350 watts per side for full range main speakers. Look at meters for output on home gear and you get the story...bass frequencies take up a lot of juice, even with efficient speakers...they simply do.

For one thing we’re discussing subs, not full range. For another thing the reason you need a lot of power for many speakers to produce bass is that they are 3 dB or 6 dB or 9dB down at very low frequencies. Many speakers are more than 9 dB down 25 Hz. Which is why you sometimes need a sub in the first place. Hel-loo! If you need a lot of power to get decent bass you’re doing it all wrong. This ain’t rocket science, folks. 🚀