Dual subs and room size

Hi. I've been considering dual subs with speaker input to pair with my Martin Logan 35xt's and not sure what I should be considering in relation to room size. My room is 17' X 10' with the equip along the long wall. I've been looking at SVS sb1000s and HSU vtf 1/3. The SVS are 12" sealed vs 10" ported hybrid for the HSU. It was suggested that I go with no more than 10".  They will support 100% music. The speakers are pretty much an 9' equidistant triangle set up and would be looking to set the subs on the outer side of the standmounts. Any thoughts or advice would be greatly appreciated. Thanks, Dave

I don't knwo the SVS, but I love my HSU!! :)

First, take a deep breath. If your main speakers are like the girl next door: firendly, cheerful, ready to accommodate others, subs are like the bastard drunken dad.  Making them work well is not as easy.  Well integrated, heavenly.  I point this out so you are prepared to do the work in advance. :)

How do you plan on doing the crossovers and EQ? Do you have existing room treatment?


Also, your room is kind of small, so I strongly suggest you plan to start with 1 sub. You may find yourself perfectly satisfied with that.

While I love my Hsu it lacks built in EQ. I make my own loudspeakers, so that’s not a problem. I live and breathe measurements, crossovers and EQ so going from measurements to a miniDSP is super easy. However a built in EQ that is push button may be a much more important feature to you, or having an EQ that is auto calibrating like a Dirac system may be what you want, especially in a room that small.

Again, room treatment should be the very first thing you deal with. THEN a sub, then EQ. Contact GIK Acoustics for great advice and affordable and effective solutions.


I have 14'x 14' room and have 2 JL audio E110's to complement my Janszen zA2.1's. The JL's are very good subs. I have the cross over and volume turned down low or they will over power the room. I'm just using them fill in the bottom octave. This works very well in my small room. I did start with one sub and I now feel two are definitely better.

The number of subs has little to do with room size or volume. You want multiple subs to get a flat response by canceling room modes. (Two minimum and three preferred.) Read the stuff by Geddes. It is pretty well established science. Use attenuation to address volume to taste after you are flat.
Yes, two subs is better, but 1 sub with acoustic treatment and eq is very very good. My point was, for a room that small, 1 sub is probably enough. So much so that the second sub may not be worth the expense.

Buy a dozen subs if you want to but if budgets and floor space matters, and I'm not ashamed to admit they do to me, then starting off with 1 sub, with bass traps and EQ may be perfect.

Personally, I would take 1 sub with room treatment and EQ than 2 subs without any day of the week. I can get damn close to perfect. So much so I no longer care about the difference, and while I may merely reduce the worst nulls, my overall response will be much closer to flat, or my version of it than having 2 subs, no matter how well placed.

But again, the buyer should make themselves happy.


I have a pair of Hsu subs with EQ, and my office is smaller than the OP's room.
I think erik is correct, the OP would probably be very satisfied with only one sub. 
Again, assuming your quest is a flat FR and not just volume I disagree. EQ can't fix nodes only constructive modes (antinodes). You will be happier with two half price subs versus one full price subs all else held constant if your goal is flat FR. If you just care about volume one sub in the corner of that size room will rock your world unless you sit in a node.

Alone EQ's use with a sub is limited to reducing the worst peaks,  however with bass traps in place it gets much more effective.

I've tested this and there's online explanations for this. Bass traps de-energize the ringing, allowing EQ's to work better, and by reducing the peaks, you can actually reduce the decay rate. It's pretty awesome.

You also get to moderately fill in the nulls. Not perfectly, mind you, but damn better. :)

2 subs assymetrically placed are better, but again, 1 sub + traps + EQ is pretty remarkable, and my suggested STARTING point for anyone.




Re your theories on bass traps, one sub, et. al. ---

Subs are good for a small room as you can adjust the bass. I had 2 12" JLs in a 12x17' room and it was great. I have the same system in a 25'x26' room now and it totally sucks. 
Smaller room, more physical impact, taking less SPL to pressurize room and feel sound waves. RE mule kick test. 

Two subs. More physical and audible impact potentially better imaging, easier to achieve a flatter response, fewer dead areas, larger mule

Treatments- always a good idea, should be part of a serious listeners arsenal. 

Levels of happiness will always vary. I went through ported SVS' and HSU' I could not settle on either. Two sealed subwoofers with EQ can be bass rewarding. Two push pull subs in sealed cabinets with EQ can be all out bass heaven.   
I call your youtube clip and present one of several online docs that goes in depth what I was trying to point out clumsily.



I should also add, I wouldn't be such a proponent if I didn't have personal, practical experience with everything I have mentioned. Doing it right is pretty damn awesome, but spend your money however you want to. :)


This subject keeps returning. I think, most agree that two subs are always better. Two good subs.
I don't disagree Inna, but in my personal spaces, 1 was so good I reached a point where I couldn't shell out the cash for the second. :)

Your own mileage and money may vary, and nothing prevents you from buying 1 now, and 1 later.


Erik, right. Just because something is better doesn't mean that something else cannot be good, it can.
Thank you all for your comments and insights. I do have wall treatment and bass traps in the front wall corners. I have large framed maps on the walls and tried to reduce the effects of the glass. You all have put forth a lot of info, much of which I'll have to digest. Simply, I was thinking two to provide a balanced stereo sound across the freqs. I don't do thumping overbass and didn't want to find my space overloaded by using two. In the end perhaps the conservative approach would be to start off with one and see how it sounds.

A single well integrated sub is invisible and works very well with stereo.
You cant tell where it is, at all. Just plan your EQ solution, or get a sub with very flexible eq bulit in.

IN fact, I'll say, you can't hear the difference of most good subs, but you sure can tell the difference of their auto-EQ. :)

A poorly integrated sub stands out like a sore thumb. :)


i run two sunfire hrs  ,and gik treatment they have takin awhile to dial in properly.I would have jl fathoms is i had the scratch.(pricey)

I hate to see you make a mistake due to some of the advice here. If you listen to music you will be much happier with the flatter FR and integration from 2 lower priced subs versus one higher priced regardless of your budget (as long as you are at a minimum quality level like the SVS you are considering). The improvement from the second sub is NOT about SPL's it is rather these other sound quality improvements and EQ alone will not get you there. You set the SPL's to your taste so you have no worries about being overpowered. The opposite occurs when you eliminate room modes via the second sub.

Regardless of what you are hearing this is not disputed in the scientific community. Do a little homework on room modes, nodes and antinodes and how standing waves behave below 60hz given that most room treatments have little effect in this range. You won't regret it. 
I generally agree with @wattsperchannel

I also very much agree that integration is much more important than getting the most massive or beautiful or well reviewed sub. Very good very powerful and capable subs are available relatively inexpensively. You may find a lot of information on that here:


However.... proper bass traps and EQ get you very close to ideal, so much that you may not want the second sub. Buying 1 sub does not stop you from buying 30 more later. Subs are not rationed per family. :) and it’s your wallet, so buy as many as you’d like. I only mean to let you know what the cost/benefits are, and that there are diminishing returns after 1 "well integrated" sub.

Lastly, I keep saying "well integrated" because subs are a nightmare for some one who does not do this professionally, or build loudspeakers, to integrate well. Whatever you do, do not expect to drop it down and have it work. It takes time, measurement, and accessories such as appropriate room treatment and adjustment for EQ, crossover, delay, phase not to mention it takes muscle to locate the sub in the ideal place. More so with 2. When I set up a sub I don’t approach it as a sub but as part of the speaker.

I’m very happy with a Hsu VTS 15, and a miniDSP unit + GIK acoustics soffit traps, but I have a background in crossover design and audio that makes this relatively easy. A sub with a push button EQ may do much for you. If you go that route then I _DO_ encourage you to ask owners. Auto EQ systems are quite variable in quality. You’ll want to hear owners experiences.

Another good source of help is the Room EQ Wizard forums. There are many people there who will help you with measurement, interpreting and setting up subs.


Thank you all for your discussions and info, I appreciate it. Been doing much reading since thing thread started and have learned a lot. Haven't made any decisions yet. My budget is $950 so my options are somewhat limited. Any specific recommendations would be helpful.
 Reading about nodes/anti nodes was thinking about my room. The room is 17' X 10' that opens to a 10' X 10' room directly behind my seat. My chair is right on the line that separates the two. Next to me is a 13" X 8" pillar. The reason I bring this up, I never calculated the smaller room  as part of my listening space. One of the articles that I was reading mentioned that this type of space could act in a similar fashion to bass traps, the sine waves will travel past my listening position and dissapate. Conversely it may appear that I am sitting in the middle of a large room although on that score there is nothing that I can do. Think of the room as an inverted two layer wedding cake. Does this environment change how I should approach bass. Or the size/number of subs. Again thanks.
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Hi Italian,

Best way to find out is to measure. :)

You can also approach this a step at a time. Get 1 sub, place it the best you can, measure it, plan your next move.

Empirical measurements are always better than theory when it comes to a specific application.


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What wattsperchannel said.
Get two used subs . For a g you can score rythmics,svs  little more and you can get two hrs sunfires i love mine . I started with one and honestly the places i could place it i heard it or i had bass issues. Added another and its less placement oriented .  I run pre outs to mine and once again that interconnection choice made a difference.. jmho 
While we're on this subject, I have a question. Did I read someplace that newer stereo releases are being mix/mastered for separation down to 20Hz (and below)? Would this be a good reason to go for two subs?
There are several industry experts which will only recommend 2 subs in a 2 channel system.  George Vandersteen and Jim Smith to name a couple.  To the point they state, for a 2 channel system,  they would not add a sub to the system until they had 2.  In my own experience,  I owned a single JL Audio F212, and I was never able to get it to blend right with my speakers,  and I felt it took away from the imaging of the main speakers.  It wasnt,  due to lack of trying, I worked for weeks on sub placement and in different rooms with different speakers,  B&W 802D2,  Revel Salon 2,  Aerial Acoustics 20T V2.  Rooms all treated.  After researching,  ultimately bought a second F212 and was blow away by the improvement.   In fact,  I didn't tell my wife I bought the second sub and was playing the system, she said,  "wow,  that is sounding really good".  What did you change?"
Corrcting myself.  It is Richard Vandersteen, not George.  
X2 karm same experience. And i just love those f112 . Pricey but it shows
Again I want to thank you for your advice and guidance, I have been following your leads. Last night I spent some time moving and adjusting my current ML orig model Dynamo sub. Wow what difference. Will continue to lock it and conduct measurements. Will be ordering one sub with a thought to two after I lock that one in. Very interesting process. Dave
The subs should disapear when set up right ( 2 will be easier imo),Although there are times i put in something like a reggae cd and it's bass heavy ,then your like "dam those subs are thumpin " .I usually back off the volume on them slightly.otherwise i rarely touch anything other then the volume on them occasionally..And room treatment is the ticket i use gik as many others