Why the fascination with subwoofers?

Those of you who think adding a sub woofer is just adding bass to a system are missing the point. A truly great sub woofer adds feeling and will not take over the system, it will just add what the mains are not delivering, and when this happens correctly with true integration the listening room is loaded by the sub and the whole room seems pressurized and the main speakers come more alive because they are now free to do what they do best...

Matt M

lewinskih01

One material aspect of their research was time delay between the subs in the room, which is something I can't do with my setup. Neither can the SWARM system, yet Noble100 and Millercarbon report very good results, so I'm intrigued.

My 4 are run with two Dayton amps, giving me the option of running stereo, mono, and with variable phase on either one or both pairs, in addition to being able to wire one or more completely out of phase. Phase isn't exactly the same as time delay, but close enough for government work. 180 degrees out of phase equates to a .025 second delay at 20 Hz. 

In any case what little I've had time to experiment with hasn't turned up any noticeable difference. Yet. This probably says more about my lack of experience.

The bass from a distributed bass array, it seems to me, is so much better than anything possible from any one or maybe even any two subs, that it takes quite a long time to appreciate. This is compounded by the fact its impossible to know where the really good bass is until you come across it, often by accident. Some recordings I always thought had a lot below what I was hearing turns out they really do. Some others not so much. Some I would never in the world have thought of having low bass surprised me. I've barely begun to scratch the surface of what's hiding out there waiting to be revealed.

Often times when it happens its not like you'd think. Almost all of what we think of as bass is guys plucking strings or hitting synth boom boom boom each note pretty much like the last. This I am now sure has more to do with the inherent inadequacy of a single sub than anything else.

Because the bass with a bass array is never like that. Each note, each drum whack, whatever, is its own unique event. And I know this is passing strange and one hell of a conundrum because at the same time its all mono its also precise and localized. Just not localized anything like the way people assume. Its clear the sense of localization has nothing to do with what is coming out of the subs.

Obviously, because I can run all 4 off the one amp and it sounds exactly the same as run in stereo. To be fair I noticed the same thing with my one Talon Roc sub. Which with its massive drivers and isobaric design ought on paper at least to be faster and cleaner than my much cheaper PartsExpress subs. But its not. Not even close. The 4 sub array is much more precise. Despite there being 4 of them. Spaced all over the room.

But because it is so much better I think means it takes a lot longer to dial in and understand. Also my time is limited and given the choice between enjoying awesome music and working to make it even better I keep coming down on the side of immediate gratification.

So sue me.

I'll get around to it, eventually. Even so its more than enough to know absolutely and for certain this is the way to go.

Really? And you would know..... how? 
Which ones have you heard?

Oh and the Swarm system is a bad joke. The people who thought this up have no understanding of acoustics in a usually sized room. It is all about reducing first reflections. All the swarm system does is increase the number of first reflections. The result is mud. It may be powerful mud but mud none the less. 

Do you use a bus to fly to Chicago? 

@rauliruegas 
Not sure why you are attacking atmasphere. He's not selling subs. Over the years Ralph has been as unbiased as I can expect from a manufacturer, even when explaining benefits of a SET, which is a product that competes with his amps. His experience is relevant to me.
Also you are taking words out of context. When he replied " that's exactly how it works" he was answering why subs added depth, etc, which is something I knew too - but the question wasn't pointed to me.

FWIW, over time I've exchanged with several knowledgeable people who do sell subs and don't, listen to their points of views and explanations to help form my opinion and then decide how to try it out myself.

BTW, thanks for the link to the Harman work. I'm familiar with it as I have Floyd Toole's Sound Reproduction. One material aspect of their research was time delay between the subs in the room, which is something I can't do with my setup. Neither can the SWARM system, yet Noble100 and Millercarbon report very good results, so I'm intrigued. In fact mine are Rythmik subs with more tuning flexibility so should do even better. And I do have means for proper measurements.

Regards

LOW bass is pretty cool for HT. I became obsessed with getting 20 hz extension in my 2 channel room and a couple of the big hitters couldn't give me anything below 40 hz even tho JA's measurements showed both these speakers were capable. I brought my big a$$ dual side firing 12" sub into the room and within a half hour I was getting smooth flat measured bass all the way to 20!  All that experience showed me was my can lighting and duct work is noisy and I brought the sub back into the tv room.Now i'm happy with 40 hz extension and find more is less when it comes to deep bass and music.

Dear @lewinskih01  :  First than all you ask to a man that's a seller always. That person not even has in his system that four subs array but already making  advise about and telling stupid things like that : " that's exactly how it works ", and this with out first hand experiences in his room/system. I don't care that he is a tube manufacturer because this at the end means almost nothing on what we are talking here. Audio kinesis is a seller too.

Of the people that I know is not a seller and has first hand experiences with more than two subs is noble 100 and he has no interest to sell you or at any one nothing but only shares his first hand experiences.

Btw, that tube manufacturer a few months ago posted in a hot discusion with me in the analog forum that he did not needs subs in his system because he has a very good system response down to 20hz with passive speakers. Obviously he has no idea about and even today he does not knows what's talking on this specific low bass/subs management and he will know when he finally has first hand experinences at his place, not before.

Measurements always can help but if I was you or @mitch2  I must ask my self:

with the two subs I have and at my seat position have I good low bass perception: tigth, full, no resonances, no overhang and pristine definition on that range and great midrange/highrange performance?

if the answer is yes then we have to add nothing, two subs are more than enough and if yes then that means that the subs location is just rigth. Will improves in remarkable way adding two subs for a way better  quality performance at my seat position?, maybe you even can't say was a true up-grade. With low bass your ears will know all about if you know how low bass  performs in a live event seated at near field position. If we don't have this kind of experiences then we need ( a must to ) to live that experiences before any move /action regarding low bass/subs. It's up to each one of us.

If you need more than a one listening seat position the a third or four subs could be better but even with 2 subs maybe you can ( ? ) do better  moving a little your subs today locations, not drastically, only little movements with. Additional you always can use a parametric eq. for those subs and all these before adding two more subs.

At the end the " move/action " we make belongs to each one of us.

I like the Harman white papers because are an abstract work/research/modeling that try to sell nothing only sharing first rate information about.

Here two links that can help all of us:

https://forum.blu-ray.com/showthread.php?t=48286

https://www.bringtheruff.com/using-multiple-subwoofers-to-smooth-bass-response/


@noble100 , I already " finished " my tests on that low bass stereo/mono recorded or not and the response on what we are listening. I will post about in the other thread following our dialogue.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

Do you have to play a mono (i.e., summed) signal from all the subs or would there be value to trying the front subs in stereo and the rear subs or one rear sub in mono to better deal with standing waves?

I'd put the side subs in mono. That's the plan in my system since my speakers already go solid to 20Hz.

Ralph: if I'm taking measurements and measure a deep valley within the subwoofer frequency, would that be pointing to a standing wave?

That would be my first suspicion!
 

For example, the kick drum dead center and the upright bass a few feet forward and a few feet left of the kick drum.
     I can only explain this by assuming that the higher harmonics or overtones of the deep bass fundamental notes's frequencies extend beyond 80 Hz and are being reproduced by my main speakers, giving my brain the clues it requires to associate the higher directional harmonic frequencies with the much deeper and non-directional fundamental frequencies reproduced by my bass system and determine the specific locations of the bass instruments.

Yup- that's exactly how it works.

Look, small bookshelf speakers begin to work effectively from 120-150Hz. I mean really flat characteristic. There are different reasons for it. So, subwoofer mast work to 160-180Hz in this case. Just if you install it at center between the main speakers, bass and main signals can look "separate". And the negative effect is just stronger if the subwoofer stands somewhere in the corner. The best idea is to use main speakers working at least from 40-50Hz and subwoofer just to 60Hz. There is another way - you can have small main speakers and TWO subwoofers, one for each channel. They must be installed under the main speakers. It is possible to buy not expensive devices (about $200 each) produced by PolkAudio company.
Vlad

mitch2,

     It was mentioned earlier that humans are unable to perceive true stereo in the bass frequencies below about 80 Hz.  Even if you were an exception, there's the problem that there's virtually zero musical content recorded with discrete L/R bass signals.  I'm aware of none in cd or lp format.
     I run my 4 subs in mono mode because of this.  As I've stated before, however, I do perceive the bass as stereo in my system on well recorded cds and 24 bit/96 Khz FLAC files even though I believe the bass is summed into a mono signal.  By stereo bass, I mean I perceive the bass as originating from the proper position within the sound stage illusion.  For example, the kick drum dead center and the upright bass a few feet forward and a few feet left of the kick drum. 
     I can only explain this by assuming that the higher harmonics or overtones of the deep bass fundamental notes's frequencies extend beyond 80 Hz and are being reproduced by my main speakers, giving my brain the clues it requires to associate the higher directional harmonic frequencies with the much deeper and non-directional fundamental frequencies reproduced by my bass system and determine the specific locations of the bass instruments.
    In your situation, since there are no recordings with discrete L/R bass channels, locating a sub in the middle of your back wall and running them all in mono would give you smoother bass that you'll perceive as stereo bass.  Adding 2 more subs, running all 4 subs in mono and positioning them where they sound the best to you will provide the smoothest, most natural, most dynamic and effortless bass that you'll perceive as stereo bass.  I'm almost certain it'll provide the best bass response you've ever experienced and it will provide sota bass response throughout your entire room, not just at a single sweet spot. 
     I can share a best practices method to optimally locate each of your 4 subs if you're interested.

Tim

@atmasphere 
Ralph: if I'm taking measurements and measure a deep valley within the subwoofer frequency, would that be pointing to a standing wave?

@mitch2 
While many records have very similar low bass recording on both channels, to be certain it works you should play a summed up mono signal to achieve this.

Do you have to play a mono (i.e., summed) signal from all the subs or would there be value to trying the front subs in stereo and the rear subs or one rear sub in mono to better deal with standing waves?

Ok, so you don't use swarm, but I take you are replicating the concept: distributed bass array playing a mono signal. Is the goal to minimize SPL variations at different seating locations? Or to optimize at the prime seat?
How did you determined you needed to break down a standing wave?

The goal is uniform bass response in a greater portion of the room including the listening positions. I've done lots of setups over the decades as I've been doing audio shows since the late 1980s; so the answer to your third question is 'experience'. Standing waves are a common problem in a lot of rooms. One time we used an Accuphase room correction device but quickly learned that it can't do anything about a standing wave. If one is present, you can put as much power into it as you like and at the null point the bass still won't be right.

So the elegant approach is to use a distributed bass array system like the Swarm, which is the best example out there.

@atmasphere 

I'd give it a shot. I don't use the Swarm but if I had it to do over that's the route I'd likely take. Duke is working on a sub system for me though- one that is integrated into a coffee table. It will be used to break up the standing wave in my room.

Interestingly, my additional two subs would go disguised as coffee tables as well. 

Ok, so you don't use swarm, but I take you are replicating the concept: distributed bass array playing a mono signal. Is the goal to minimize SPL variations at different seating locations? Or to optimize at the prime seat?
How did you determined you needed to break down a standing wave?

Regards

I bought the Focal Sopra No 1’s knowing they would be light in the bass region.  Just picked up a pair of JL Audio F112 suns with custom floor stands.  Wow!  I had an old Definitive Technology sub before but having two subs of much higher quality makes a huge difference.

Dear @millercarbon and friends: You are rigth about that full range speakers down to 20hz not only are expensive but don't realy gives the " rigth " low bass not only to 20hz but almost does nothing for below 20hz frequencies that exist in the recordings.

The first problem with those " 20hz " speakers is that are working through electronics ( amps ) that was not designed to fulfill the specific needs of those speaker woofers , there is no " total control " down there with universal amps and if those amps are tube electronics the problem is worst.

Other problem is the frequency response that those woofers handled by design, normally goes to 150hz to even 350 hz depends the overall speaker design.
When the recording signal ask to reproduce a 20hz frequency those woofers at the same time must be reproducing other way higher frequencies/harmonics making the the IMD goes really high making a damages to all the system frequency response at the seat/listen position.

In my point of view and along the other disadvantages that others of you already posted " against " full range speakers in reality is a big mistake to invest on it.

Even those full range speakers can be up-graded with a pair of self powered sealed subs working in true stereo fashion where the full range speakers will be working as a satellite part of the room/speaker system.

I agree with @noble100  that low bass is a separate music reproduction signal and mid range/highs an independent signal reproduction system.

I already posted in other thread the next link that's a scientific papers made it by Harman International where they stated all what we need to learn about the use of subwoofers in general and for home systems:


https://pdfs.semanticscholar.org/00da/51387c572cfd27c0256cb15e44e976a1a72e.pdf

coming from that link we can read:


"  Four subwoofer at the wall midpoints (configuration 11) was the best practical configuration in terms of MSV. Two subwoofers at opposing wall midpoints (configuration 6) was nearly as good and also offered stronger low-frequency support. Configurations with more than four subwoofers were not found to be advantageous, especially when cost is factored in. These results appear to be generalizable to reasonably dimensioned rectangular spaces [19] . ""


They are not talking about wired stereo or mono.

So at our seat position normally two subs are enough and I'm for sealed subs designs against open/reflex ones that gives some problems on way up resonance frequencies. If you takes the Wilson Alexandria or MAXX 3 bot that goes to 20hz have that problem and both are reflex designs.


I can't remember who speaks in the thread about the integration of very fast ribbob/electrostatic speakers with " slow " subwoofers and here an explanation about that tells us does not really exist that " slow " bass subs response other that the one coming from each instruments:


http://www.soundstagenetwork.com/maxdb/maxdb061999.htm


The other subwoofers " main approach " to even or disappears standing waves in the room in reallity are not the main targets for add a pair of subs but to put at minimum the overall speaker system IMD kind of distortion as I already talked here:

https://forum.audiogon.com/discussions/do-you-think-you-need-a-subwoofer/post?postid=310058#310058

the other main target is that the low bass system " management " if we do " perfectly " always we will have a way better whole room/system frequency response due that are the low bass range and its developed harmonics whom tame and put the overall signature at the mid range and high frequency range.
The low bass range is the frame of what we are listening at our seat position.

So as better room/speaker system low bass range as better quality whole room/system levels.

As a " side " advantages adding subs gives better low bass quality, deeper low bass, tigther bass response ( less overhang. ). When I said deeper low bas I'm not saying down to 20hz only but even lower that that where belive it or not exist more information that what we could think.

In other thread I said the importance that the subs it self can comes with a truly low THD at 20hz and 100db SPL, mines around 0.5%. One gentleman there tolds that is not important if the response is evenly in the low bass but I think that we can have evenly bass response with low THD and evenly bass response with higher THD. Maybe I'm wrong but if I was any one of you I always will look for a low THD for my susbs: this is a good place tostart along sealed kind of design.


Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

hifidream,

     I forgot to ask a few questions about your custom dba system in my previous post.  I hope you don't mind, I'm just curious about a few things:

1. What brand and model were the initial 2 subs you added to your system?
2. What brand and model were the last 2 subs you added to your system?
3. Do you operate your 20.1s full-range or limit their bass output?
4. What upper cutoff frequency are your subs set at?

Thanks,
  Tim

Hello hifidream,

     Congratulations on creating your own custom distributed bass array system for your Magnepan20.1 speakers.  I know the 20.1s have very good bass performance in stock form with 2 large planar-magnetic bass panels in each speaker that all output down to 25 Hz.  Not full extension to 20 Hz like many good subs but close and very respectable.
     Counting each pair of bass panels as a sub,  I would suggest you're actually using a total of 6 subs in your room/system.  While 2 aren't outputting bass that's fully extended, they're both outputting the exceptionally fast, articulate and smooth bass provided by planar-magnetic panels down to a deep bass level of 25 Hz.  

      Since we've both experienced the amazing seamless integration with even fast planar-magnetic panel speakers (whether mid-level models like mine or top of the line models like yours) and the high quality bass produced using  4-sub dba systems, I think it's safe to assume you'd agree that the dba concept works exceptionally well.

Tim

If you can hear the sub, then it's too loud.  A good friend of mine always has his up a bit, and he complains that he cannot hear mine.... but you sure miss it if I turn it OFF.  In my studio I run stereo 15" subs... they make great monitor stands, but they do not call attention to themselves unless the music demands.   

@yogiboy ,
Vandies don't 'need' subs, but having them really fleshes things out, subtle but noticeable. Quatro's have built in subs with equalizer.
B

@brskie,
I own the non-CT Treos, and have 2 2wq subs. I am very happy with the combo. So much so, I will probably get the new Sub 3's when I sell the 2w's.
If it were me, first I would ask Johnny.
Barring that, I would think getting 2 Sub 3's with the Treo's might possibly be a smidge better than the Quatro's(as you can distribute the bass within the room)- Only if you have limited room/placement options-which is my problem.
The Treo's are a tad smaller than the Quatro's and I can place them easier in my cluttered LR/DR.
As far as amps go, the Pass should be a nice match. I have no experience with AR.
One thing I would offer is that Vandy's like zero feedback amps.
I use Ayre and Atma-Sphere.
Bob

I am a former AudioKinesis owner and really respect Duke's work. His Swarm is a great system. I took a similar path as I wanted smaller drivers and boxes. I use 8" drivers in 0.4 cu. ft. sealed boxes. The four boxes sit at various spots in the room. I use a Beveridge RM-3 active crossover with LP and HP boards cut at 100 Hz, Linkwitz-Riley 4th order 24 dB slope. Amplifiers for above 100 Hz are either Atma-Sphere or Music Reference, the bottom a vintage Luxman. I use this set up with my ESLs and box speakers and all I can say is I wish I did this a lot sooner. I can't see going back.

Why do you think you will need a subwoofer with any of those Vandersteens that you auditioned at Audio Connection? I use a subwoofer with my small stand mount speakers that only go down to 75hz. I would think those full range Vandersteens would not need a subwoofer!

Sorry everybody, I posted this morning after the first page and not at the end of the thread.
This is a very timely topic for me as I am about to buy some new speakers. I have listened to both the Vandersteen Treo CT and the Quatro Wood CT at Audio Connection in Verona NJ. I was very impressed with both. These demos however were performed using John Rutan's house Aesthetix amps.
My amp is a Pass X-250.8. It is powerful and has very good bass control. I would love to bring it in and demo the speakers with my electronics but the problem is that it's so heavy to put in the car along with my pre and drive for 1 1/2 hrs to Audio Connection to do a more proper comparison between the two speakers. Also, my wife and I will be moving in a couple years when she retires so my listening rooms will change over time.
My two questions are:
1) Is it better to get the Treo CT and add a Vandersteen sub that can be positioned in appropriate locations as we move or just get the Quatro CT and not bother with subs?
2) What's the consensus on adding an AR REF 6 pre in the future to compliment my Pass amp, or could anyone recommended a different similarly priced preamp?
Thanks so much for any advice.
Bruce

kink56,

     The real strength of a 4-sub distributed bass array system is with musical content. There are 4 subs with 10" drivers strategically positioned around the room, driven by an abundance of power with the sole responsibility of reproducing bass frequencies between 20 Hz and whatever the crossover frequency is set at.
     The result is very fast bass which is very smooth, detailed and agile.   There's also the added benefit of very good bass dynamics due to the ample power reserves. 
     Prior to using the AK Debra dba system, I was unable to seamlessly integrate very good deep bass response with my fast Magnepan 2.7QR dipole panels with either a single or dual subs.  I perceived that bass as a bit lagging and disconnected. I believe the nature of the bass produced by good dba systems will allow them to be seamlessly integrated with virtually any pair of main speakers.
     The fact that 4-sub dba systems are also excellent for ht use is just  icing on the cake.

Tim

psyco P I totally agree with you. I think the subwoofer thing is a big step in the wrong direction. I sincerely believe most listeners are not satisfied with the sound of their systems, and they mistakenly believe that what is missing is " the bass "  

While it may be that some subwoofers don't integrate well in stereo mode, this has not been my experience with REL subs, have owned a number of their models, favorite is the TZero which is my current model, they make every speaker I have sound better.

1 - Agree that subwoofer integration in a system can be difficult/problematic

2 - I'd rather have a speaker that goes accurately down to 40 than a full range that is less accurate. Martin Logan has achieved integration of a cone woofer with an electrostatic panel at least once - the original Monolith, and it was hugely expensive and still only went down to 35 hz. I prefer my CLS, which are a bear to drive (~83 db/1w) and dip to 1 ohm, even though they are 3 dB down at 40 Hz - you won't find a more accurate speaker

3 - I have other speakers that integrated a subwoofer, with separate powered crossover, separate amps and push pull drivers that are 3 dB down at 23 hz. They were expensive in terms of cost and in terms of requires amplification.

4 - I also have speakers in my main system that are capable of low bass without multiple amps etc. - 20 hz 3dB down  Ideal, expensive of course, but a complete solution without worrying about system integration.  I use them as the main speakers for video as well as the only speakers for audio, but I also have a couple of powered subs that are 3 dB down at 16 hz used only for video.

Out of curiosity, I hooked them up in the main audio system to see if there was anything missing, and can say that  with few exceptions (organ recordings that have content from the low C pipe (32') of a full sized organ, which is 16 hz, or a rendition of the 1812 Overture using real cannon fire) You aren't missing anything if your speakers can go down to 30 hz or so (remembering that you only hear down to about 20 hz and below that you are feeling it).  Bear in mind that the lowest note from a bass guitar is 41 hz, or from the low A of a concert grand piano at 27.5 hz.

My conclusion - by all means play around with subwoofers if it pleases you, but IMHO it is better to have an accurate system that won't reproduce the very lowest notes than one that will, but at the cost of poor integration between sub and mains.

Final comment - I find it amusing/ironic when stereo addicts worry about having speakers that will accurately reproduce notes lower than is contained in 99% of music  but end up buying what are essentially low base rather than true subwoofer add-ons (and some of them are listening to ipods most of the time).

This thread is well worth reading (this subject keeps coming up again and again).

https://forum.audiogon.com/discussions/hz-how-low-for-full-range-music

I have a pair of 12" sealed subs playing mono and been wondering about adding one or two more with the goal of flattening at the main seat. Would love to know your take on this.

I'd give it a shot. I don't use the Swarm but if I had it to do over that's the route I'd likely take. Duke is working on a sub system for me though- one that is integrated into a coffee table. It will be used to break up the standing wave in my room.

Ive never hooked up subs and dont feel I’m missing anything. Different speakers bring different results and it just seems somehow obvious when any part of the sound spectrum is not quite right and time to move on to another speaker. Had some Monitor Audio one time and dont get the attraction there. In my system at the time at least. Thin and a bit etched. My Harbeths are all around a good sounding speaker. I suppose for home theater some may want that all enveloping sound of the lower frequencies ... I never got into home theatre,, Just doesnt interest me but can understand why some do.  @kink56   what you are saying  does makes sense and I have to admit I've always wanted to check it out.   Dont know that I will anytime soon.  

low E on a 4 string bass is 41hz.  A lot of speakers can't even go flat to 40hz.  Low B on a 5 string bass is 31hz.  Lowest frequency on a piano is 27.5 hz. 

Few "full range" speaker go much lower that 40hz. That is a whole octave missing. And a subwoofer designed for home theatre is not what most audiophiles want.  They want one that plays music convincingly.  In fact home theatre speakers are not what audiophiles seek either.  Now there are true full range speakers, but they are typically very expensive and quite large.   Often a good subwoofer paired with high quality monitors will be a good option, even preferred by some. 

This is a very timely topic for me as I am about to buy some new speakers. I have listened to both the Vandersteen Treo CT and the Quatro Wood CT at Audio Connection in Verona NJ. I was very impressed with both. These demos however were performed using John Rutan's house Aesthetix amps.
My amp is a Pass X-250.8. It is powerful and has very good bass control. I would love to bring it in and demo the speakers with my electronics but the problem is that it's so heavy to put in the car along with my pre and drive for 1 1/2 hrs to Audio Connection to do a more proper comparison between the two speakers. Also, my wife and I will be moving in a couple years when she retires so my listening rooms will change over time.
My two questions are:
1) Is it better to get the Treo CT and add a Vandersteen sub that can be positioned in appropriate locations as we move or just get the Quatro CT and not bother with subs?
2) What's the consensus on adding an AR REF 6 pre in the future to compliment my Pass amp, or could anyone recommended a different similarly priced preamp?
Thanks so much for any advice.
Bruce

LISTEN to @hifidreams.  He knows what he hears, and it is all good.

Jump on 2 subs asap dude!!

+1 @millercarbon The wide unknown is a fun place. Someone was asking about a cheap good crossover, check out Mini DSP. With a digital crossover you get exact slopes and have the option of doing room correction with Room EQ Wizard and can have even more fun with Multi Sub Optimizer. I prefer a Mini DSP with IIR over FIR filters as the IIR filters operate at 24/96.

I’ve heard my Magnepan 20.1 speakers full range with no subwoofers and they sound great. I added two properly integrated stereo subs and listened a year like that and it was even better. I added two more subs and measured/corrected the room and the “WoW” happened. Nothing is boomy, just accurate full range bliss. I don’t have to turn up the system nearly as loud to hear full range. In the end I’ve spent almost as much in subs as my mains which by all accounts are SOTA. That’s how important I feel the lower octaves are in music.

Human hearing below 20Hz is described in this paper:
Hearing at low and infrasonic frequencies Moller H, Pedersen C S - Noise Health

Good site with audio tests including subs:
(this direct link also tells when you are hearing sub overtones- not good)
Low Frequency Harmonic Distortion Subwoofer Sound Test

In the end there is the human. For me a system reproducing music is sufficient
with 30Hz at -3dB. For electronic and movie sound effects the rotary sub might
be useful ;)
Rotary woofer - Wikipedia

PS. I stood once next to a 16Hz organ pipe and all I could experience was wind.

     Since bass sound waves behave so differently in any room versus midrange/treble sound waves in the same room and good bass performance is more difficult to achieve in any room versus midrange/treble performance in the same room, I'd suggest it makes sense to consider our system as 2 systems,a bass system and a midrange/treble system, and it's logical to deploy and optimize the bass system prior to deploying and optimizing the midrange/treble system.
     Starting from scratch, the best method for deploying and optimizing bass performance in any room that I'm aware of is a 4-sub distributed bass array system.  
     For those already owning high quality full range floor standing speakers that are capable of outputting accurate deep bass down to at least 20 Hz, however, I believe it may be the exception to the general strategy of getting the bass performance optimized first.  This is because these types of high quality speakers are unique since each speaker, in effect, already contains a high quality sub due to the exceptionally good deep bass extension of each speaker's bass section.   
     In these scenarios, I would suggest first positioning the floor standing  speakers to optimize the midrange/treble response as well as the stereo imaging at the dedicated listening seat.  Once this is done, the positions of the first 2 'subs' in your custom 4-sub dba system are established.  From here, it's just a matter of buying 2 more subs and positioning them in the room so that bass response is optimized at the dedicated listening seat. I even believe the 2 additional subs don't need to be of the same quality level or size of the main speakers' bass sections for the dba concept to work effectively. 
     This method is a bit of a compromise from a complete Swarm type dba system but I believe it will provide very similar results.  I believe this because the main dynamics involved in the very effective dba concept would still exist; 4 asymmetrically positioned subs with each creating bass room modes.  At the listening seat, the brain processes the multiple room bass modes (bass peaks and dips) by summing and averaging them which results in the bass being almost magically perceived as detailed, natural and smooth. 
     Voila, psycho acoustic principles at work. The dba concept absolutely produces the best bass performance I've ever had in my room and system.  I was initially very skeptical and I know just my words will likely convince very few but I also know even a brief demo would convince everyone.

Tim

@atmasphere 

Hello Ralph.

I see you use a SWARM system, so the sub woofer frequencies play in mono on a distributed basis. Similar to Earl Geddes approach/theory. Geddes argues for 3 to 4 subs playing the same signal to flatten frequency response at different locations in the room. I was wondering if you are using this approach for the same goal, for flattening at the main listener seat, or other?

I have a pair of 12" sealed subs playing mono and been wondering about adding one or two more with the goal of flattening at the main seat. Would love to know your take on this.

Regards 
Horacio

Full range cabinets are going to be rather large.  It can be much more convenient to go with smaller speakers plus a sub in a less conspicuous spot in the room. 

My understanding is that having the deep bass coming from more than one speaker invites phase cancellation.  

I assume that taking the deep bass out of the speaker handling the low mids and bass frequencies will help to make the audio clearer. 

I have one of my subs near a wall and under a window in my listening room, and when I want sound on the deck I put a pair of speakers in the windows with that sub. The deck specific speakers (old KEF Q10s...great sounding things) are powered by a separate amp (a trusty 100 watt Adcom) getting its signal from the main preamp, and the sub's signal is from the indoor mains little tube amp so I have to turn the window sub up a little...I have a volume control on the outdoor amp as it's way hotter than the indoor speaker's amp...all of this works very well, and unlike mapman I get my deck bass goin' which is good for the plants and lets my neighbors know I'm having more fun than they are. 

Great subject. Right now I am in the process of doing room treatment and my bass sounds great. But I will still add 2 subs. I have demoed a few in my room and they really open things up.  My mains have excellent base, but the lowest of frequencies are missed and I want them also. Thanks for all the info, helps alot.
++++on adding subs.

There are phase reasons to use subs but anyone who has to ask this question is not an audiophile anyway, and this poster is only baiting and so one worm is all you get...

Many do try to do just that. Look around however, it quickly becomes very obvious the hardest most expensive thing you can find is two quality speakers with true 20 Hz bass. They essentially do not exist. Turns out (read on) that for reasons of physics they cannot exist. Which is why they don’t.

@millercarbon
This statement appears to be false.


My speakers at home are made by Classic Audio Loudspeakers. They are the model T-3.3.


They have a pair of 15" woofers. One of the them is the TAD 1602, which has a free air resonance of 21 Hz. Are you really trying to say that a speaker like that in a properly tuned bass reflex cabinet (my speakers are the size of refrigerators) can't go to 20Hz?? They seem to have plenty of undistorted output at 20Hz in my room.

@gdnrbob 

I am glad you are considering the Vandy subs.

Hi Bob, you responded to a second post that wasn't clear on its own.
I am not considering Vandy subs but rather I considered the Vandy M7-HP passive crossover, which costs about $2,500.  I probably would have already tried it except my main speakers do great bass (twin 9-inch woofers in a sealed, i.e., acoustic suspension, enclosure) down to about 40 Hz, so I really need to cross over lower than the fixed 100 Hz design of the Vandersteen passive crossover.  Currently, I am using twin Aerial SW-12 subs which sound great and utilize a remote control that can be used to easily adjust the output level for different recordings. 

I am considering adding a third SW-12 sub to the existing two, which are operated as single stereo channels and are placed in the front corners outside of my main speakers.  I will place the third sub along the rear wall or in one of the rear corners outputting a summed bass signal.  I cross them over between 40-45 Hz and keep my baseline output level (0 position) at a low'ish level to just fill in the lowest frequencies rather than to "shake the building."  IMO, if subs sound bad, this is where most sub users have made the mistake - the level is too high. I sold bass reflex (i.e., ported) speakers that went lower but excited room vibrations on about half of the recordings I listen to.  Adding one sub did not correct that situation but switching to speakers only going down to about 40 Hz and adding two subs absolutely corrected it.  Bass is now solid and controlled and rarely interacts with the room.

If I were starting over, and didn't already own the Aerial subs, I would look very hard at Duke's Audiokinesis Swarm Subwoofer System (four subs) as a reasonably priced alternative to obtain great bass.

Interesting comments from all. I see that a carefully chosen low frequency subwoofer can be potentially helpful. I have some Vandersteen speakers and I could supplement them with Vandersteen sub(s) as an experiment to see if I am missing something. Thanks for the responses.

IT's probably true subwoofers get a bad rap with audiophiles because in many cases they are set up in a manner that adds too much bass which can also obscure the higher frequencies.  

But like anything else, its just a matter of doing it right, using the right sub set up the right way.    

The best setups do all frequencies in music one might hear well, generally accepted as being from 20hz to 20000hz.   Older ears will lose their ability to hear the higher frequencies over time  but not the lower.

Many people today like loud rock music.  Live, these songs are aided by towers of lousy speakers driven by even worse amplifiers that the move so much air the stadium shakes. 

People who have grown up with this thumping noise and gut-punching "music" want to reproduce that in their home and car systems; subs help IF they are efficient enough to work with their internal amp (powered) or your external amp--needs to be rather powerful unless you have Cerwin-Vega or other very efficient bass-heavy speakers.

Orchestral music that features actual music or sounds and harmonics (cannons, for example??) that enter the lower frequencies that humans can hear also require speakers that reproduce those frequencies accurately.

Systems that incorporate large bass cabs, like the old Mark Levinson HQD system, which used 24" Hartley speakers in huge cabs, actually CAN reproduce those frequencies given enough CLEAN amplification and the proper crossovers, etc.  Such systems not only give the listener the "live" experience, but also provide (as accurately as possible in a reproducing system) the live orchestral experience.

Finally, film buffs who have exotic home theater systems use them to reproduce the artificially-enhanced soundtrack of their fav films showing buildings blowing up--not really in the 20HZ range, but ENHANCED is the key item here--and other loud, gut-punching sounds that are really in the lower mid-range, but who's quibbling when your room is shaking and your stomach is pounding?  

Soon, we will have holographic films where the action will take place IN YOUR ROOM, or seem to, anyway.  Sound in those cases has to envelop the viewer/listener, and the love of the gut-punch or explosion at 120db is what people seem to want.  Well, until their ENT doctor gets ahold of their hearing tests, anyway...

Cheeers!