Is two Subs better than One?

What is the general consensus? And why?
With most studio-mixed music, in which the bass is often mixed into a single channel, one sub is plenty.

But if the lower frequencies are mic-recorded, AND mixed into stereo, two subs CAN (but won't always) make a difference. This seems to be particularly true with pipe organ, in which the phasing can cause some details to drop out when the bass is played back monophonic. But in these rare cases, even two subs can have the same result if not properly placed in relation to the room and listener.

Ultimately, YOUR ears are the judge. It's a good idea to demo a second unit, and spend some time at home experimenting. You might discover results contrary to what your most trusted sources preach to you, and your money ultimately should be spent according to your own experiential preference.
Two subs will even out the bass response in the room. Also, each sub won't have to work as hard since you will be winding down the volume on each. So yes, two subs is better.
I was just thinking about the same thing: in my room 28'x24', how would a set of 2 two Rel Stadium compare to a sigle Rel Stentor? Maybe some of you already have experienced this set up, I hope.
Jimmdavis has good advice, experimenting is key. I've done it both ways. It often really depends on where you set the crossover, the sub's capabilities, and on your room/placement.

The only way to really get proper bass response is to install bass trapping, if you have not done this. I use Realtraps and they are spectacular. Easily one of the best purchases I have ever made. Then all your equipment will sound better, and you may decide that you do not want *any* subwoofers. But at least can make a true decision about the quality of bass.

If I have to go to 70-80 Hz with the sub then I would usually prefer two. For most of my recent setups I only need <35 Hz, so that works better and simpler for me with one sub. And when I do it that way I prefer the overall sound with the single in my rooms.

Also, the sub's performance will matter. Even if the filter is low, if the sub is producing a lot of harmonics then you will be able to localize it, and two can help minimize that effect. Better subs tend to produce less of these extra frequencies.

For music, if you have good mains and room then it really doesn't take much contribution from a subwoofer to balance out the last octave.

In my case, one better REL or two lesser REL, would only augment my four full range speakers for the last octave for music, and LFE for HT. Thanks for your sharing your thoughts.
How many "general concenses" would you like? There are definite criteria for either choice ;-)

If your mains peter out at 100Hz or higher (or need to be high-passed above 100Hz to avoid distortion) then you definitely need two subs to preserve stereo directionality (which is present down to around 80 - 100 Hz) The cons are that two subs are hard to place so they integrate seamlessly with the mains/room -- the biggest issue being phase matching to the mains at any given location.

If the mains go low enough to require sub-assist only below 80 -100 (or preferably 50 - 65 Hz) then one sub is preferred. It can be placed almost anywhere, but right between the mains is preferred. If you can't do that, then place the sub at your listening position, and walk around the room noting all the spots where the bass sounds best. Use one of those spots to locate the sub ;-)
I have 2 subs and believe that configuration beats one sub.
No offense but it's: "are two subs better than one?
Foster, OK then my answer is "not necessarily". Which way is actually "best" I think depends on the sub's selected low frequency cut-off point.

For filling in low frequencies up to 50Hz, one sub is better. Since the brain can't localize a source below about 80Hz, placement isn't that critical as far as imaging is concerned.

Above 100Hz, two are definitely better than one. Between 50 - 100 Hz it's a tough call, but I'd still start with one. Then, if there's insufficient low-frequency imaging (meaning the bass doesn't seem to come from the mains) then two subs placed somewhere near each main will provide more realism -- but then room acoustics will require more adjustment.
I would think that two subs are better then one, but my question is: are two medium sized subs like rel stadium
better then one larger stentor (for the last octave)?sorry if am am repeating my self.
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Bob Reynolds, great paper just what I was looking for. The paper seamed to say that a fixed position 2 channel System does not have a problem like the multi channel multi seat position environment. Therefore, is it safe to say that one sub in the corner is as good as one in the center wall? Which position is better?
Or is two opposing center wall Subs still much much better?
my undestanding is that two subs in the opposite corner as as good as two opposite center. Not a word referring to the issue: one large sub vs two smaller once.
Baam, one v. two depends on the high-freq at which one plans to roll off the sub(s). Once that decision has been made, the size of the unit(s) regardless of whether using one or two, really depends on what SPL (sound pressure level, in Decibels) one needs to reach in a given setup/room. And THAT decision will be determined by the type of music on listens to, and whether HT will be a part of the system or not.
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Hamburg, I think many people forget that that paper is primarily about providing smooth bass across a fairly wide seating area.

Actually, the paper is about provding 'repeatable' bass over a wide area. It assumes that you will correct the roller coaster bass curve so that it is smooth at your listening location. The objective of the study is to determine how many/best locations for multiple subs so that the measured response at every/most locations is identical. With that being the case, you can then correct it to be smooth for everyone.
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Dear Hamburg: Yes, IMHO two subs are better. Why?, well these next info are what already was/were posted in another thread where are an explanation of the whys with a little different treatment:

+++++ " My approach is different from yours, mine goes to obtain ( first place ) a better quality performance in my main speakers and in second place to achieve a better quality bass performance that could goes lower too.

I use two subwoofers in true stereo way to achieve those targets, the first one ( that you can't achieve with your approach of one subwoofer. ) is obtained lowering the Intermodulation Distortion ( main speakers ), this means to stop to ask to the woofers ( main speakers ) the simultaneous reproduction of frequencies between 20Hz and 200HZ or higher( if yours goes flat to 30Hz then you still have some distorted response at 20Hz that makes higher the IMD subject/problem ), this means ( again ) that we have to choose a crossover frequency higher than what the main woofers are handled : in my case 60 Hz and in Eldartford 80Hz.

In this manner the main woofers will be free/less stressed of the low bass reproduction working from 60Hz-80Hz up and lowering ( cleaning in deep ) the IMD: this fact makes a huge improvement ( in any speaker including yours ) in the quality sound reproduction of the main speakers ( it is not matters what you think about or what I think about, lowering the IMD/HD always improves the quality performance of " that " driver, physics laws. ).

The second advantage on this approach is that now the low bass frequency response not only goes down through the subwoofers but with a better quality bass performance due that those bass frequencies will be reproduced for " drivers /amplifiers " that were designed specific for those kind of bass frequencies. " +++++

+++++ " Where the subs can help us ? :

Intermodulation Distortions ( harmonic distortions ): Almost any three ways speaker ( all two ways/one way ) has it's crossover frecuency ( low driver ) between 150Hz and 450Hz. I can assume that any of ours speakers system goes down flat ( at least ) between 60Hz to 20Hz.

What does that means ?, well that a single driver has to reproduce frequencies/harmonics from 20Hz/60Hz to 150Hz/450Hz. With that kind of frecuency range here exist a great intermodulation distortions that put it's " color " on the sound reproduction.

You have to imagine that that single woofer/driver has to reproduce, at the same " time ", a 30Hz frecuency along a 350Hz frecuency ( Downunder in your case from 20 to 450Hz ): here is where exist that IM/HD that gives heavy distortions in what we hear ( there is no perfect driver: moving coil, electrostatic, ribbon, etc.. The speaker designers has to choose the best " trade offs ", but the distortions are there. ): less clarity, less resolution, less precision, less natural balance, less pitch, les, less, less......., and this is what we are really hearing: LESS MUSIC.

What happen when that low driver is free from those frecuencies ? ( main speakers: monitors or full range, it does not matters. My main speakers are flat to 22Hz and only 5db +.- at 18Hz and I have benefits with the subwoofers integration to my system ), below 60Hz:

SUDDENLY the " lights are on ", your music/audio " life " its born: the mid bass is clean, the midrange is clean, the highs are clean: high resolution every where ( the distortions are almost gone ), and now you can really hear for the first time the MUSIC through your home stereo audio system: what a pleasure!!!!!. " +++++

Mark the second subwoofer is not to obtain more bass but to even and smooth the room bass response:

08-02-05: Skushino
After adding a second sub to my system, there was smoother bass response. Again, this isn't about louder or stronger bass, in fact, I was seeking lower, smoother bass. Ironic that the path to this goal was accomplished by adding a sub! My girlfriend is a great listener and concurred that bass was better quality. Since I returned the second sub (on loan from my neighbor), I miss the performance " +++++

+++++ " this quote comes from a friend ( Agon ) that send to me for this thread. The research/investigation or whatever were made by: Audio Perfectionist Journal and Vandersteen:

+++++ " Suppose I told you that you could add two
components to your system that would reduce
intermodulation distortion in the midrange by a
factor of two or more, dramatically improve the
resolution of midrange and high frequency detail,
double or triple the dynamic range capability of
your system without changing your existing
amplifier or speakers and improve imaging more
than you can imagine. You would probably be
interested, right? But wait, there’s more.
These same components would allow the
amplifier to maintain tighter control over the
speakers in the mid-bass and lower midrange.
They could extend bass response to infrasonic frequencies
while lowering bass distortion and
improving the system’s ability to accurately convey
the rhythm and pace of music. And these
same components could virtually eliminate the
uneven response at lower frequencies caused by
room standing waves.
Does all that sound too good to be true?
Are you concerned about the possible cost of all
this improvement? If all this is so easily achievable,
are you wondering why you’ve never heard
about it before?
Let me assure you that all these sonic
improvements can be yours and I’ve been conservative
in my estimates of the level of audible
improvement you’ll get.

and goes on and on...... Conclusion: two subwoofers!!! +++++ "

this is another quote on the subject:

+++++ " - There is no single external / stand alone amplifier that can work or do a better job than a low bass dedicated amplifier like the one that comes with a powered subwoofer:

think that this dedicated bass amplifier was designed/tailored to match every single woofer parameter: impedance, frecuency response range, damping, power, distortion, etc, etc,...

- It is not only this dedicated amplifier what makes this subwoofer approach/technology ideal to handle the low bass octaves.

The driver/woofer is designed/tailored too for that specific frecuency range.

There is no passive FRS ( full range speaker ), at any price with any amplifier, that could beat a self powered subwoofers in that frecuency range. When you have and hear the subs on your system you never can live again with out those subwoofers.

Here we have to remember other important issue: the best subwoofers are SERVO CONTROLLED, this characteristic give to the subwoofer a heavy advantage over a FRS about the low distortion that a well designed subwoofer had against a higher distortions on any FRS.

- With a subwoofer we not only gain with a lowest harmonic distortion but with a lowest intermodulation distortion ( main speakers )too. This means better quality sound reproduction.

- Other advantage is that with the integration of two subwoofers in a true stereo fashion to a full range speakers system: the main ( s ) amplifier will be free of those high power consumtion low bass frecuency range: this means too, better quality music sound reproduction. No exception.

- Other advantage with the subs integration is that facilitate the integration of our mains speakers to the room.
" +++++

+++++ " I discovery ( for my self and I'm not saying that I discovery for all and I'm not saying that was the first one or that it is the only " true ". ) for my self ( testing one and again ) and not looking for, that the subs make a lot difference but for other things than the low/deep sound reproduction: suddenly I learn about!!!! and the experience is so " unique " that I put this thread to share about with all of us, the name of the game: LOWERING THE IMD/HD of the main speakers ( almost any ) with the integration of two subwoofers!!! " +++++

Regards and enjoy the music.
Dear Richard: You can't believe the paramount importance of that subs subject till you have the opportunity to experience on your own system where you will be surprised of the high level of the quality performance improvement on the response of your system: you will discovery a " new world "!! and from that first moment you can't go back !!!

Almost all of us when we are talking of subwoofers immediately think on " more and better low bass ", almost non of us think in how/where we really take great advantages to improve the quality sound reproduction of the main speakers and the main amplifiers too, well the integration of subs to our systems can/could do that and more!!!

Regards and enjoy the music.
thanks Raul for your lenghtly and detailed explanation. It's likely that it is the case for most but not all situations. Each of my Vienna Acoustics Mahler have two 10 inch woofers that only take care frequencies from 70hz down. It would be silly for me to cut them off. it would defeat the purpose of the having those speakers. I believe that if the mains are made with quality it's an overkill to cut them out, especially in my case. That's only my opinion based on my experience.
As now, I have a stadium iii and soon as I get a good deal and budget I will buy a stentor, and then I'll try to integrate the two... We'll see...thanks
I have to disagree regarding the frequency and localization issue. I propose that if you believe that you cannot 'localize' a sub that is cutoff below 50 Hz, then try this.

Put the sub, LPF set at 50 Hz, at the 1/4 point between the speakers. That is, halfway between one speaker and the midpoint between both speakers. I guarantee you'll be able to tell which side it's on, provided that your speakers are set up properly, and in a room that's a decent size. The effect gets more noticeable, naturally, as you move the sub closer to one speaker. And when you've proven to yourself that you can 'localize' it, the case for two subs over one is practically irrefutable.

I was a non-believer before I tried this myself, having subscribed to the common knowledge. Sorry, but this myth needs to be debunked for the good of the audiophile community.
Absolutely yes. Running two SW-12s with a set of Aerial 20T's and it helps even out the base response of the overall room. One sub is in a corner boundary so it's turned down and has a different crossover versus the sub that sits in the middle of the space and doesn't have the room boundary support.
Dear Baam23f: The Mhalers are very good/clever thinking design and that's why they choose to lower the normal IMD/HD, that exist on almost other speaker designs , crossing from midrange to the low drivers around 70-80hz and this is exactly what I'm talking about.

Now, you choose too a very well matched amplifier ( bryston ) because the Mhalers goes down near 2 Ohms in the low bass and the Bryston has a very low output impedance and the power to handle easy.

+++++ " I believe that if the mains are made with quality it's an overkill to cut them out, especially in my case.." +++++

I agree with you.

+++++ " I will buy a stentor, and then I'll try to integrate the two " +++++

I like and respect your wide " open mind " on the subject. Which are my thoughts here?:

well, IMHO the integration of two subs in full stereo fashion ( by-passing the Mhaler low drivers. ) in your system could help ( maybe ) not only to go deeper on the low bass but more important than that could be two things ( between other less important ones ) : leave the Bryston free of work in the 70-80hz/down frequency range and in this manner is probable that the Bryston improve its quality performance in the main remaining frequency range.

The second thing is that because the low mid-bass/low bass frequency range will be handled by two subwoofers where its drivers were specific designed for that range ( same as Mhalers but these ones goes to 30hz -5db and -10db at 22hz and we don't know with which distortions level. ) and where those drivers are paired with amplifiers that match exactly the subwoofers parameters: frequency response, electrical impedance, damping, power, distortions, etc., it could be that you could have a quality improvement.
Like you say: " We will see ".

Regards and enjoy the music.

>>Absolutely yes. Running two SW-12s with a set of Aerial 20T's and it helps even out the base response of the overall room. One sub is in a corner boundary so it's turned down and has a different crossover versus the sub that sits in the middle of the space and doesn't have the room boundary support<<

That's interesting.
I am in a similar situation. One sub in the corner and another one in the center (at leas until I decide whether to keep one or both. The problem is that one is a Stentor and another one is a Stadium. Any suggestion on which one should be placed in the corner? -at least as a starting point. Moving big subs around in my living room is very challenging.

I used to own the Mahlhers for 4 years til quite recently. I cannot imagine wanting a seperate sub for them They produce copius amounts of bass.
I'll agree with Raul in one aspect - gop buy the biggest, smoothest SS amp you can with great current and the Mahlers will sound even better.
I think raul's idea of cutting your bass off and replacing with subs is plain and simple stupid IMO with the Mahlers.

Dear Downunder: It is no surprise here that like always you don't " read " what is posted.

this was my answer to Baamf23 post about:

+++++ " I believe that if the mains are made with quality it's an overkill to cut them out, especially in my case.." +++++

I agree with you.

then he posted:

+++++ " I will buy a stentor, and then I'll try to integrate the two " +++++

and this was mine:

+++++ "
I like and respect your wide " open mind " on the subject. " +++++

along this I only give my thoughts about, nothing more.

Your post: +++++ " subs is plain and simple stupid .." +++++

like always speaks for who you are.

Regards and enjoy the music.
Yes I know and agree with you Downunder, I could easily and happily live without a sub. They don't need it, The mahlers are that good! My living room is however cluttered and large, the idea is the add a stentor to augment just and only the last octave, as rel claims, to pressurize the room a little bit more, and to be able to use the sub for LFE tracks. Thanks for your inputs. If the sub turns out unnecessary I will sell it, that's my plan. Thanks for your inputs.
Baam, BTW I just bought a Stentor III. It is a great sub and used for what you are doing makes sense as you know how your room sounds.

Raul, you certainly are the master of taking one's comments out of context. I did not say " subs is plain and simple stupid".
What I said was cutting off mahler's bass and replacing it with two subs is plain stupid with a speaker like the mahlers. I am sure Baam bought the mahlers as he luvs the full range big dynamic sound, not so he could cut the bass off and replace with $50 digital amps inside two subs.

You have your opinions, I have mine.

Baan is certainly doing the logical thing for his system and setup.

OK, if you are in the US, where bigger is always better, 2 is better. Anywhere else, depending on room size of course, one well choosen sub is fine.
2 Subs Sound better to me. After all the opinions I thought I would buy a second DD15 Subwoofer. After setting it up but not yet finely tuning it; the volume needed to be decreased to synch with my Wilson 7's. I could definitely sense a fuller better balanced base. The mid and upper frequencies were more focused due to the fact that base appeared to fill the room better. With the base originally localized more to one side, the Wilson midrange on the opposite side did not feel as intergraded.
I guess bigger is better.
I added a ACI Titan II LE as the second sub to my system and I don't think I will ever go back. My room is 13.5 x 17.5 and the second sub just make everything sounds better from 2-ch music to 5.1 HT movies. I'm using Anthem processor which has 2 sub outputs so hook-up is very easy.
Lynhnn, just curious, but at what frequency to you cross over your subs to your main speakers?
The default THX is 80Hz which can be customized to a diff number by the Anthem setup menu. I have tried various frequencies like 50, 60, 70, 80,90 ... and for my front speakers, I set it to 70Hz for music mode. I set it 80Hz for cinema mode. For other speakers in the system, I just use THX, which is 80Hz.
If you have large front speakers which can handle low frequency without distorting the sound, you can have it lower to 80Hz. Or if your speakers are so small, 100Hz can be set so the sound is cleaner.
If I have one sub, I would try to set it around 60Hz so more bass can be pumped out at my main speakers. But it again depends on how low the speakers can handle.

Lynhnn you split right and left out of Pre Amp into two pairs and run each pair to each Sub. Therefore the right Sub becomes the right channel and left, the left channel.
Each sub needs to be equalized separately. The DD series connects the master to the slave by a serial cable to control volume. Richard
Dear Samuellaudio: Some Preamps and processors come with two main outputs but if yours comes only with one pair then you have to use a Y connector where the left output goes to the left sub and the right output to the right sub, that's all.

Some preamps comes with a tape loop design where you have one pair of line outputs where you can take the additional " signal " to the subs instead the Y connector.

Regards and enjoy the music.