Are big subwoofers viable for 2 channel music?


In thinking about subwoofers to get for a large future listening space (30' x 30'). So far there seems to be a lot of great options for smaller subs for music.. such as the rel s812. Now my main focus will be music but I do plan to do some home theater on the system and I do enjoy subs that reach low and have strong but clear sub-bass. Would a large sealed sub still be able to provide clean tight bass that digs low and thus satisfy both duties. Can it ever match the speed and precision of a pair or more of rel 812s? Something like PSA S7201 or Captivator RS2?

A realize a smaller sub has a smaller moving mass and thus for a given level of power would be faster than a bigger sub with a bigger moving mass (driver mass). But a large sub would have to move less to achieve the same SPL and would reach lower.

Anyhow what do you guys think? Thanks.
smodtactical
With subs it is not a question of which. It is a question of how many.
https://systems.audiogon.com/systems/8367

Get whichever ones float your boat. Just be sure to get four. Or more.
It's good to have headroom, and with a space that size, having multiple subs will help with that as will using larger more powerful subs. I have two Rythmik F25 subs and two SVS SB13 Ultra subs in my system. I'm really happy with the quality/ quantity of bass in my system. 

I dont have any experience with either sub you mentioned. Both look like beasts! The PSA sub appears to be geared more towards home theater. Which doesn't necessarily mean it can't do music well, but it might not be optimized for music. 

You might get more feedback on subs like those on avs forums or audioholics.
RELs play really low from my experience.  I’m going to try Ryhtmik next time and see if they offer more punch.  
@b_limo  which rel are you using?
@millercarbon so you would do rel 6 pack 812s over say dual JTR RS2 or S7201 ?
I had an S3 SHO and returned it.  Had a T9i before that.  RELs are awesome in that they play low and have crazy finesse but they don’t really hit you in the chest.

Check out a pair of Rythmik F18’s for $3700.  

Another interesting option would be to buy 4 Tekton 4-10 subs and do a swarm.  That would be $3200 and you’d have 16, yes, 16 10” subs 😵

Ask big greg what he thinks of his Rythmik’s...his SVS SB 13’s are beasts too.  Note that he is using 4 subs.  Seems more is more better!
"Would a large sealed sub still be able to provide clean tight bass that digs low and thus satisfy both duties."

Your question revolves around integration of the main speakers with the subs. Just like an internal cross-over between a tweeter and a midrange driver, it’s not so easy to get it right. It can take many months or so of fine tuning to make the integration seamless. Both the cross-over point and the phase must be set correctly. If it’s not done right, the bass can sound bloated or slow. The room is a very important factor here - as well as the main speakers. 

Are the main speakers floor-standers, large monitors, bookshelf monitors or satellite monitors?

With the main speakers:
- How low do they go?
- How quickly do they roll-off?
- Do they offer a ’clean tight bass’ just by themselves? If not, don’t expect any sub to deliver that.

When a manufacturer says that the main speaker goes down to 40hz. It doesn’t really mean much unless you can measure it in your room - at your listening chair. Does the speaker have a sharp drop at 40hz - or a slow roll-off at 40hz. This is similar to a 1st order cross-over vs a 3rd order cross-over.

- Quickness and punch could be in the 50-100 Hz region. This probably would be covered by your main speakers. Much depends upon what you’re referring to. Is it a kickdrum, a piano, an acoustic upright bass, an electric bass or a pipe organ. The initial whack of a kickdrum could be around 120hz, but the resonance continues downward to 30hz.

- Digs deep would be in the 20-40Hz region. This is where the subs primarily work. Yet, at this LF, multiple subs would be needed to do it right. See AudioKinesis Swarm.

The argument of sealed vs ported is also a misnomer. Much depends upon what works best in your room. If you have 4 subs, there can be two of each.  Also, I can tweak my power subs by using different power cords. I prefer silver for added quickness.
The mass/speed issue is not real.

What is real is the integration with the room.  Smaller sub = less bass = less problems.

Otherwise, bigger is better. :)

A well treated room, including bass traps, is the best place to start.  Talk to GIK Acoustics for advice.
Ask big greg what he thinks of his Rythmik’s...his SVS SB 13’s are beasts too.  Note that he is using 4 subs.  Seems more is more better!
I've been super happy with the Rythmiks.  I like the servo system and Brian and Enrico have been helpful when I've had questions, even though I bought mine second hand.  I've had a few SVS subs and they are great performers also.

Using 4 subs is great.  At first I only used all 4 in my home theater system, but since setting them up for 2 channel listening I find the music more enveloping and engaging.  On many music pieces where the bass isn't prominent, all you hear is clean tight bass that doesn't draw attention to itself.  When playing something with a lot of bass in it, they come alive and give you the feel of listening to live music.
Stack 'em high like the Tekton 2-4 sub maybe?


I'm sorry I mean the 4-10 sub, couldn't edit.
There was a recent discussion about this in another thread where the OP was an owner of a Gotham V2 SW:

https://forum.audiogon.com/discussions/jl-gotham-f212-v2-vs

Here’s a link to a YT video featuring 2 line arrays of the baby brother in the REL performance lineup which is the 510 and an introduction to the REL philosophy by John Hunter REL CEO.

https://youtu.be/I4KPfVu3toU

REL lineup goes

Reference series
1. REL 25 Reference
2. G1 v2

Performance series
3. 212se
4. 812se (replaced the S5 SHO which replaced the REL S5)
5. 510se (replaced the S3 SHO which replaced the REL S3)

T series

Be sure to listen to the part of the Demo @ 10:45. It’s a quite impressive demonstration of the REL’s ability to integrate with the main speakers.

I have a single S5 SHO which was recently replaced by the 812se. It’s a fantastic performer and I would say the value champion in the REL lineup is the 812se.

Based on my experience with REL, I’d think you’d be elated with the 2 channel performance and also quite satisfied with home theater as well.

I am thinking of 2x 2 stack of REL 812se for your room.
You can call REL directly and they will help you with recommendations.

Besides eliminating room nodes with multiple subs, you also want to integrate seamlessly with mains in both presentation and speed. Your mains will determine where you need to be in terms of sub-woofer sizing.

GLHF!
Hello smodtactical.

     There are many advantages to using 4 subs in what's called a distributed bass array (DBA) system.  Using 4 subs, that are each rated to have a capacity of outputting bass down to 20 Hz, results in no single sub being required to operate anywhere near its limit, the cumulative bass produced will effortlessly and accurately reproduce whatever the music or HT source content demands down to the deepest audible bass frequency of 20 Hz and the bass will be fast, smooth and detailed enough to seamlessly integrate with any pair of main speakers you choose to utilize. This high quality bass will also exist throughout your entire large room and not just at a single designated listening seat.
     You have the option of either creating a custom 4-sub DBA system with 4 subs of your choice or buying a complete 4-sub DBA system kit such as the Audio Kinesis Swarm system for $3K reviewed below by the Absolute Sound:
https://www.theabsolutesound.com/articles/audiokinesis-swarm-subwoofer-system/

     Due to the large size of your future room and your desire for high quality deep bass performance, I suggest you utilize a minimum of 2 good quality subs, if you're mainly concerned with high quality bass performance at a single designated listening position and 4 good quality subs if you prefer even higher quality bass performance throughout your entire room.

Best wishes,
     Tim
Tim would you go for 4x rel 812, swarm or dual rs2 / s7012?
OP must have missed the very first post. Tim and I are on the same page. In fact we have almost identical subs. https://systems.audiogon.com/systems/8367 Main difference is I built mine, with help from him and Duke, while he bought Duke's Swarm. Also I have an additional 5th sub, the Talon Roc. Which is how I know the more the better.

Like the first post said, its not a question of which, its how many, and the more the better. 

Subs in a system are like horsepower in a car- more is always better.
" Tim would you go for 4x rel 812, swarm or dual rs2 / s7012?"

Hello smodtactical,

     I'd recommend the Swarm because:

1.  It'll be simpler to setup since you'll only need to properly set the volume, cutoff frequency and phase controls once on the included 1K watt class AB amp/control unit for all 4 subs, rather than individually for each sub with the other options.
2.   It'll be much more aesthetically pleasing in your room than the other options.  Each sub is relatively small at 12"wx14.5"dx28"h, is supported by 3 conical spiked metal footers, have the speaker wire terminals hidden by being located on the bottom and are positioned with the 10" driver facing, and about 1-2 inches away from, the wall.  Once properly positioned, the subs look like attractive wooden pedestals in the wood of your choice.  You can also utilize them as small end tables if you'd like.
3.  It would probably be the least expensive option, unless you know of a seller who offers large discounts on REL subs.

     Overall, four subs will also perform about twice as well as two subs in terms of bass power, speed, smoothness, dynamic impact as well as the levels of detail and seamless integration with your main speakers.  I'm not certain but believe the 4x REL 812 option has the potential to marginally outperform the Swarm but would be more expensive and require the setting of the volume, cutoff frequency and phase controls individually for each sub.

Tim 

I have a pair of REL 212s, main speakers with their own powered subwoofers. So far the best sub position has been to place them just a bit beside the listening position, slightly to the rear. Without one of the various room measurement programs everything seem like a crapshoot. 
Not to say they haven't improved the bass and overall presentation, but there remains questions as to whether they are optimized. 
Thanks guys lots to think about.

While a pair of Rythmik F18’s is undoubtedly awesome (I say that being familiar with the F15), a quartet of smaller subs (say, the F12) may be even better. Place two of them as close to your listening position as possible, to maximize " visceral-ness".

The F12 is available with either an aluminum cone, or a lower-mass paper one (the F12G). The F12G has been optimized for music, the F12 for all-around use. Get two of each!

If you find the dual-opposed design---popularized by Seaton---appealing, check out the newish Rythmik G25HP, which I would much rather have. The Seaton is just a couple of woofers in a box; fine for home theater, not for music.

If you've got the dough! Brian gives a 10% discount on multiple sub orders. That'll help: the F18 sells for $1630-$1850, depending on finish. Sure, why not? You have a big room, so you don't have to worry about overloading it.

All the Rythmiks share the family DNA: detailed, nimble, no overhang or slop (they're described as "stopping on a dime"). Lean & clean ;-) . And they all play into the teens. The difference between models (other than the unique OB/Dipole Sub) is in their maximum output capabilities. The F18 puts out 114dB at 40Hz (1 Hz below the lowest note produced by the standard 4-string bass) with less than 5% distortion, and 99dB at 16Hz (the lowest note on a pipe organ's bass pedals) at less than 20% (in the world of subs, that's low distortion).

I had PSA before, very powerful subs and Tom is a great guy to deal with but like Chuck and Tim stated and explained it is a matter of how many not how powerful, for two channel systems definitely a swarm or array provides what you are looking for, you can select from existing of the shelf subs or go custom, a big part of it is how are you planning to integrate the 4 (minimal qty) subs,

I went custom and currently running 4 passive subs and could not be happier
BTW my custom is Duke's (Audiokinesis) Swarm not "custom made by me"
I used the term custom because you could customize the amount of subs, amps etc. when purchasing from Audiokinesis
Duke always suggested the benefits of increasing the amount of subs beyond 4 (6,8) although for space and practical issues 4 is a good number, if I would have the space I would have go for 8 hanging 2 on the ceiling for vertical plane coverage as well.

Miller's 1st reply was right on target

Hello smodtactical,

      I agree with bdp24,   that four Rhythmik F12 subs would perform well in a DBA configuration and that four F18 subs would likely perform just as well but with a bit more deep bass power and impact.
     I think it's important for you to understand a few facts about how humans perceive bass:

1.  We can generally not locate bass tones (determine exactly where the sound is coming from) below about 80 Hz and the deepest bass tone we can generally hear is 20 Hz,  Our bodies can feel deeper bass tones below 20 Hz but we generally can't hear them.  Also, there are very few musical instruments that are even capable of producing bass tones below 20 Hz, pipe organs are the only ones I'm aware of.

2.  Because of this, we perceive all bass under about 80 Hz as mono and not stereo.  Recording engineers have known this for decades and have been summing all bass below about 100 Hz, as well as filtering out bass frequencies below about 20 Hz, since the 1950s.  This is also why you can safely disregard any suggestions of positioning subs in your room like main speakers, with a carefully positioned left and right speaker.
     In other words, there's no such thing as stereo deep bass.  Best in-room bass results will be achieved by operating your subs in mono mode and positioning each sequentially for optimum bass performance.  I can explain exactly how to do this, regardless how many subs you ultimately choose to utilize in your room, in a future post.

3.  Virtually all commercially available musical content produced in the last 80 years, has the bass below about 100 Hz summed to mono and bass below 20 Hz filtered out.  So, even if you did place your subs in a left and right stereo physical configuration, there's a complete lack of content with stereo deep bass to play on them. 
     My main point, again, is to disregard any suggestions or notions of positioning or operating your subs for stereo playback.  Just operate them in mono mode and position each for best bass performance.
    Beyond the above, it mainly comes down to cost and convenience.  The Audio Kinesis Swarm 4-sub DBA system costs $3K and will produce high quality bass in your room down to the audible limit of 20 Hz. I've never auditioned any Rhythmik subs but believe they are high quality subs at reasonable prices.  I also think it's likely that utilizing four F12 or F18 subs in a DBA configuration in your room would outperform the Swarm complete system.  
     Of course, the decision is completely up to you.  I just want to make sure your realize that either Rhythmik option option will cost significantly more and will be less convenient to setup since you'll need to set the volume, frequency cutoff and phase controls separately on each sub, rather than once for all four subs on the Swarm.  
     However, I also believe that utilizing two F12 and two F18 subs would perform very nearly as well as four F18s in your room, helping with the cost but not the convenience.

Later,
 Tim
I just want to make sure your realize that either Rhythmik option option will cost significantly more and will be less convenient to setup since you'll need to set the volume, frequency cutoff and phase controls separately on each sub, rather than once for all four subs on the Swarm.
Not owning a Swarm system I may be missing something, but I would think that having the ability to fine tune each individual sub would give one more flexibility and customization in their setup.  When I set up my four subs I took SPL readings for each sub to adjust the output so that they would be equal from my listening position.  I have one sitting just a few feet from my listening position and another on the far side of the room.  It doesn't seem that having them all at the same level would be a good thing.


Four independent subs allows for maximum adjustability and flexibility. The controls on the Rythmik plate amps are the most extensive of any line I’m aware. They include:

- Continuously-variable Phase Control knob providing 0 degrees to 180 degrees of rotation (0 ms to 16 ms delay).

- On the non-XLR models, both high level (speaker binding posts) and line level (RCA jacks) hookup.

- Continuously-variable x/o filters from 25Hz to 120Hz, 12dB/octave and 24dB/octave, presets at 50Hz and 80Hz.

- High/Medium/Low Damping switch.

- 1-band PEQ with Bandwidth and Gain control.

- 14Hz/20Hz/28Hz Extension Filter switch.

- Rumble Filter switch..

- On most models both Line In and LFE In inputs.

- Two XLR models, great for sub locations requiring a long interconnect. And the XLR2 model provides Master/Slave operation for any number of subs, should you not want to adjust them separately.

And don’t forget, the patented Rythmik Direct Servo-Feedback circuitry. Plus, woofers designed by Brian Ding and manufactured by TC Sounds (you hardcore subwoofer guys know THAT name ;-) .

Rythmik. At least look into them.

I have a medium/ large area and use 2 HP Rythmik 15" subs.  They do anything you ask them to do. High damping acts like a speaker. Start and stop on a dime. I believe it's the servo design. You wouldn't know I have subs until they're called upon. I use them for music and movies. Actually, you still dont know the subs are there, but I dont have speakers that go that low. They are absolutely seamless. 

I did have my audio set up by a pro. Took 5-6 hours for HT setup, but it can definitely be seemless.

I suggest 2 f18s for your room, then if needed, you can always get 2 more. I doubt you'll need more. You do get a 2 sub discount. 

Good luck
 
big_greg and bdp24,

I agree with you both that four independent subs allows for maximum adjustability and flexibility. I know from personal experience, however, that this level of adjustability and flexibility is not required for excellent bass performance results using the Swarm system.
Audio Kinesis does state that bass performance can possibly be improved by inverting the phase on one of the four subs in some rooms but I noticed no improvement in my room with any of the subs having their phase reversed. Also, their suggested method of phase inversion is simply to reverse the pos. and neg. wires at the sub terminal connections.

big_greg: "I have one sitting just a few feet from my listening position and another on the far side of the room. It doesn’t seem that having them all at the same level would be a good thing."

My listening seat is positioned along my rear wall between two of the four subs, one positioned about 8’ away along the left side wall and the other about 3’ away along the right side wall. The two other subs are both about 20’ away along the front wall. All are operated in mono mode and at identical volumes. I perceive the bass on both music and HT as coming from the front of the room and never perceive the bass as coming from the subs nearest me to the right and left of my listening chair.
I believe this is due to the efficacy of the scientifically proven DBA concept that works exceptionally well in virtually any room and with any pair of main speakers.
This DBA concept takes advantage of both how bass sound waves behave in domestic sized rooms and the accumulated psycho-acoustic knowledge concerning how humans perceive sound at various frequencies. I can state with certainty that the 4-sub DBA concept works exceptionally well in my room and I believe it will work equally well in virtually any other room.

Tim

The typical and common 2-position phase switch (0-180 degrees) found on many subs is far too crude for creating a seamless blend between a sub and a loudspeaker. The continuously-variable control provided on all Rythmik subs is what you want. That allows one to find the best acoustic position in the room for a sub (regarding the room's locations of eigenmodes: areas of high- and low-pressure low frequency energy storage), then using the phase control to get the sub and speaker to be in phase as much as possible.

The Rythmik website has a technical section covering all these matters in great detail. Well worth reading, even if you choose subs from a different company.

The PSA sub appears to be geared more towards home theater.

Hey @big_greg and @ smodtactical

That couldn't be farther from the truth. I'm here to tell you that psa subs have a uncanny ability to disappear with sheer musicality when they're playing music with any gear at any price point. Tom Vodhanel of psa doesn't even advertise his speakers. They are sold by word of mouth. That should speak volumes. Remember Tom Vodhanel was the V in SVS subs. My PSA V1801's are an astounding value and I use them primarily for music.

I gotta go with millercarbon on this one. Let's say you've got the biggest and baddest sub on the planet, you're only gonna turn the gain up what 2,3 or 4 maybe? Because you're going to set the gain and volume to what's comfortable to you and you listening pleasure right?

Guess what happens when you add 1 more sub to equal 2? And then you add 2 more let's say at the back of your listening room, mancave, theater room or whatever - spread out somewhat for a total of 4. Suddenly you're enveloped by smooth bass all around you where you actually don't have to turn the gain on your bass subs up much at all to get the distributed array benefits of beautiful bass.

It's just another way of thinking (or technique) when using subs. It didn't click for me for a long time, but when it did...You don't need monster subs like the PSA S7201 to get the best bass. Although, 2 PSA S701's equal 4 subs and the effect of 4 subs will be realized there too! 
Big subs are viable for 2 channel systems.

i keep my subs below 24” drivers. That’s the ideal size for most rooms. Perfect, in fact. 24s put the right amount of movement where it needs to be. I angle mine up at 45 degrees. It’s wave simulated bass sources the best. I power them with 800 watt per side IGBT amps. They do like power.
@tyray

"The absolute best-in-class performance from an American made subwoofer. The S7201 is a high output, high performance powered subwoofer destined to set the new standard in home theater bass."

That's from PSA's website. Which isn't to say it can't be good for music also. 

A couple of other things. I use 4 subs in my two channel system. I'm not knocking PSA subs, I own one, and I'm aware of the pedigree. I think they're well made, sound good, and represent a good value. 
The OP was asking specifically about home theater and the psa S7201. Thanks for the correction big_greg.

That psa S7201 looks strangely similar to ’stacked’ pro style marshall amps I’d see at concerts when I was a kid. I must be having flashbacks!

Sealed subs sound wonderful and have a massive mean ass bass attack without cuffing. And that is not to say all ported subs have cuffing. I especially like and prefer forward firing subs.
Hello tyray,

     The correct term for a distracting sound coming from the ports on some ported subs is chuffing, not cuffing.  Chuffing does not occur on sealed subs because no port is utilized.  You are correct, not all ported subs have chuffing.
     The conventional wisdom is that sealed subs are best for music and ported subs are best for HT.  The Audio Kinesis subs I use have port plugs so they can be operated as ported or sealed subs.  
     With these subs, I don't perceive a distinct advantage on music operating all 4 as sealed.  I operate mine without the port plugs as ported because I think they sound equally as good as sealed and the bass extension goes slightly deeper.
 
Tim
@tyray Actually, he asked about subs for music that would also work for home theater.  "Now my main focus will be music"
@noble100 I found the same with my 4 AK subs, without the port plugs they sound very good so the sealed vs vented sub dilemma I have a feeling it depends on other things, maybe the dimensions (length and diameter) of the port in proportion to the enclosure? Not saying sealed is not good, just that I assumed for music sealed was always better and Duke prove otherwise.

It is funny you said "they sound" the beauty of bass in my system is I forget about the subs, I don't tweak them, they are part of the room's furniture, I totally forget these exist, I don't "hear them". The only time I realize they are there is when I play rock and my wife starts screaming because candles and ornaments she put on top of the subs start falling off, otherwise to me they don't sound.

And again I'm not trying to promote my subs, PSA, rhytmik, excellent gear which I respect, but (again) quantity (4 or more) and ability to integrate them is more important than the actual brand.

Just that Duke of Audiokinesis if I'm not mistaken was the 1st "commercially" to approach the array, the concept and theory comes from Geddes I believe?


Oh ok, thanks again BigG! In that case I would recommend @smodtactical to get vented subs - and chose a manufacturer, shop or store that will let you hear them whether it be walk in and or has a decent return policy.

Also note that audio stores that are still open - now will a great time to go and listen as hardly no customers will be frequenting the store and you may get a chance to hear the differences between a sealed, vented or ported sub in a very quiet place to judge for yourself.

But if you do get a chance to hear a vented, ported or sealed sub - do so. Don’t take ours or anyone else’s word as a fact. Listen for yourself.
@luisma31,

I agree with you and want to expound further. I think it has always been a misnomer that ported and vented subs are better home theater and sealed subs are better for music. They both can be used for either with excellent results. A high quality sub regardless of port/vent or sealed will always sound better than a sub of less quality and design. I don’t think a mechanical sub (vented/ported) will outperform a non mechanical sub (sealed) of less quality, period.

Maybe the ’sealed vs ported/vented’ thing was used for pure selling points of the two different subs as they both sound good when done by a good designer in any situation? I don’t know.

@b_limo brought up Tekton subs and I see where their top tier subs use a proprietary sub structure known as a ’Tesla Valve’ to vent the sub enclosure with a ’patent pending design as a set of restricted flow vents, which combines the benefits of both sealed and conventional ported designs’.

I would enjoy a chance to here some of those Tekton subs but at this time are only available by internet store with a high return shipping price which may or maynot be to much for some.

But if you’re just starting to think about investing in subs and haven’t made an initial investment, Tekton with their Tesla Valve designed subs just maybe the way to go too?


luisma31-
And again I'm not trying to promote my subs, PSA, rhytmik, excellent gear which I respect, but (again) quantity (4 or more) and ability to integrate them is more important than the actual brand. 

millercarbon, first post-
With subs it is not a question of which. It is a question of how many.

https://systems.audiogon.com/systems/8367
luisma31 again-
Miller's 1st reply was right on target 


luisma31-
Just that Duke of Audiokinesis if I'm not mistaken was the 1st "commercially" to approach the array, the concept and theory comes from Geddes I believe? 


Not sure he was the first, or even if he is the most prolific supporter, but around here he may as well be. 

The distributed bass array concept is not new. It has been around a couple decades now. Probably was Geddes who "discovered" it. As with so many things on this subject Duke has nailed the many reasons why so important a revolution in audio has yet to gain much traction with the masses.

DBA doesn't fit the standard bigger/newer/more powerful marketing mantra. DBA doesn't provide any advantage to any particular manufacturer or design. DBA doesn't help sell at all, because think about it, what manufacturer is gonna come out and say woweee! Our sub is so good you need four of them! Right. DBA is hard to understand. There's guys here had it explained to em a hundred times now, still don't get it.

The one thing DBA has going for it is, it actually works. 

Been just over a year now that I've had mine. A lot of research was done first. One of the bigger surprises was yes, this guy Geddes, figured this out as part of a Phd dissertation. Painstakingly measured and mapped out bass response in a whole bunch of room with a whole bunch of speakers. Took the raw data, applied the physics, figured it out. Genius! The physics of DBA is rock solid. 

At one point in the planning stages of my DBA project Duke thanked me for having the faith to do this. But as I told him then there was no faith involved. It is a matter of pure logic. This is the most rock-solid speaker project a guy could ever hope to find. There simply is no way of screwing it up. You build four, or more, and it just works. Its only when you try and do it with one or two that you have problems. Impossible, insurmountable problems. 

Literally impossible. Yet even now there are those who persist in pushing the same flawed paradigm that always and everywhere leads only to failure. 

With subs its not a question of which. Its a question of how many.

Its not often a doctoral thesis can be boiled down to something so simple. But there you go. Thank you, Dr Geddes!







@smodtactical --

Are big subwoofers viable for 2 channel music?

Unequivocally, yes. In fact, when practically feasible and without obstructing acoustics (and I’d go to great lengths to challenge named obstacles here), I’d much rather go with 2 big subs vs. 2 smaller ones to maximize and accommodate BOTH music and movie duties. Should you go quad-style immediately or eventually, not least with a room as big as yours, don’t settle for 4 smaller subs (i.e.: anything below 15"), because while they can make quite a load of noise, very clean bass even to a point, you simply won’t achieve the headroom desired, indeed mandatory if you want truly clean, effortless and relaxed bass at any SPL. "Enough" simply won’t cut it (it’s a severe "hifi"-disease to neglect the importance of headroom); much more than enough is what’s called for, be that 2 or 4 big subs, and once you hear/feel it, you’ll know why.

Luckily, headroom where bass goes isn’t as much about price as it is size (in addition to numbers). Offerings from JL Audio’s Fathom series, great as it may be, are simply overpriced, and yet the likes of Robert Harley would love to tell you that the Fathoms are exactly what big(ger) bass is about; that price necessarily follows size into the stratosphere. He is however, and sorry to put this bluntly, dead wrong and misleading here in his stuck-up high-end approach. Quality design, high efficiency, big size and proper implementation IS high-end bass reproduction, and it doesn’t require a minimum of 2" thick cabinet walls, luxury finishing, weighing half a ton and costing even more to get you there.

As I’ve stated previously: price isn’t the real issue here, size is, and by that I mean people are more willing to pony up the big dough for a smaller, more high-end looking product than going for the bigger, cheaper and more "unassuming" variant. Audiophilia will tell you it’s PA or home theater earmarked, not "hifi," and claim big size is just a bad, Mr. Simple Joe excuse to have bragging rights about exactly that: big size and SPL capabilities. Accommodating physics however, these are core parameters in the pursuit of great bass.
luisma31:
"It is funny you said "they sound" the beauty of bass in my system is I forget about the subs, I don’t tweak them, they are part of the room’s furniture, I totally forget these exist, I don’t "hear them". The only time I realize they are there is when I play rock and my wife starts screaming because candles and ornaments she put on top of the subs start falling off, otherwise to me they don’t sound."


Hello luisma31,

You’re mixing up 2 different factors when properly incorporating subs into an audio system: seamless integration of the subs and the sound quality of the subs.
Yes, seamless integration of the subs requires they only become active when the source material demands the reproduction of bass frequencies at or below the selected cutoff frequency. This requires a good knowledge of one’s main speakers’ bass extension performance and a bit of experimentation with the sub’s volume and cutoff frequency controls to augment the bass optimally.
I’ve found that a good guideline, for good integration between subs and the main speakers, is to try and set the volume and crossover frequency as low as possible with the bass still sounding powerful, smooth, fast, detailed, dynamic and natural when activated. I’ve also found that a pair of subs allows the bass to integrate with the main speakers about twice as well as a single sub. Four subs, positioned in a distributed bass array configuration, will integrate about twice as well as a pair of subs and integrate seamlessly with virtually any pair of main speakers and in any room. Eight subs, positioned in a distributed bass configuration in a room, are solid grounds for divorce in most states.
However, seamless integration between subs and main speakers is only one factor in achieving good in-room bass performance, the other is the sound quality performance of the subs. Just like main speakers, the sound quality of subs varies. Fortunately though, there are numerous low distortion, good quality subs that reproduce high sound quality bass sound waves.
To further complicate matters and just like the woofers on main speakers with deep bass extension, it’s not sufficient that subs launch high quality bass sound waves into the room. These high quality bass sound waves must arrive at the listening seat in the same condition for the bass to be perceived as high quality.
In general, the bass is the hardest part of the audible audio spectrum to get right in most systems and rooms. This is primarily due to the fact that bass sound waves are very long and omnidirectional which behave much differently than the much shorter and directional midrange and treble sound waves in typical, domestic-size rooms.
I’ll spare all the details right now, but this means that the woofer positions within the room launching bass soundwaves, whether within main speakers or subs, must be precisely positioned in the room to guarantee these sound waves arrive at the listening position unaltered so that the bass is perceived as high quality, with no bass peaks, dips or nulls perceived.
Given these facts, it’s easy to realize that achieving high sound quality bass at one’s listening position is much more difficult using main speakers with deep bass extension, that are normally positioned within the room to optimize midrange, treble and imaging performance and not bass performance, than using separate, independently positioned subs are capable of achieving. Also, bass integration and sound quality are both improved as more independently positioned subs are added to the room, with the majority of bass sound quality benefits attained through the presence of 4 subs.
The above is why I decided to treat my system as 2 systems, a bass system that I optimize by using a 4-sub Audio Kinesis distributed bass array system and a midrange/treble/imaging system that I optimize by using a pair of Magnepan 3.7i main speakers. Overall, this results in a high quality and full-range audio system that I really enjoy.


Tim
Thank you Tim for adding details
Lusima31 wrote: "I found the same with my 4 AK subs, without the port plugs they sound very good so the sealed vs vented sub dilemma I have a feeling it depends on other things, maybe the dimensions (length and diameter) of the port in proportion to the enclosure? Not saying sealed is not good, just that I assumed for music sealed was always better and Duke prove otherwise."

Thank you Luis!

Arguably what matters most is the in-room frequency response. The ear is far more sensitive to frequency response than to time-domain response in the bass region, so the superior group delay behavior of a sealed sub is not a significant factor in sealed vs ported. (This is somewhat counter-intuitive, and is among the things I learned from Earl Geddes.)

Imo the correct "target response" for a subwoofer would take into account the effects of boundary reinforcement. "Typical" room gain from boundary reinforcement is about +3 dB per octave south of 100 Hz, according to a couple of different sources, but obviously it will vary with the specific acoustic conditions.

So let me try to explain what I believe to be the primary reason why sealed subs tend to sound better than vented subs: In general a sealed sub starts rolling off higher than a vented sub, but its rolloff is more gentle; whereas a vented sub is "flat" down to a lower frequency, then rolls off rapidly. Factor in room gain, and vented subs tend to have exaggerated low end above their inherent rapid rolloff, which tends to sound "boomy" and/or "slow"; on the other hand, room gain synergizes pretty well with the gentle rolloff of sealed subs. (This is all without factoring in EQ.)

The target response for my Swarm units in ported mode is the approximate inverse of room gain: They gently roll off at about 3 dB per octave from 80 Hz down to about 20 Hz, and then the rolloff accelerates rapidly below 20 Hz. Not saying this is the only valid approach, but it seems to work pretty well.

Luis again: "Just that Duke of AudioKinesis if I’m not mistaken was the 1st "commercially" to approach the array, the concept and theory comes from Geddes I believe?"

That’s correct. When Earl described his subwoofer concept to me, I immediately asked him if I could license it. He said no, that I could just use it. So the Swarm uses Earl’s ideas with his permission... but anyone else can use them as well, no permission required. He has trade secrets which he keeps to himself, but the distributed multi-sub concept is not among them.

Duke
I found the same with my 4 AK subs

I had PSA before, very powerful subs

for two channel systems definitely a swarm or array provides what you are looking for, you can select from existing of the shelf subs or go custom, a big part of it is how are you planning to integrate the 4 (minimal qty) subs,

I went custom and currently running 4 passive subs and could not be happier

@luisma31,

Would you mind describing your setup and the AudioKinesis gear used?

Duke,

I’m very close to becoming a customer in the future but can a customer use their own passive subwoofers of choice? Or do I have to use AudioKinesis designed passive speakers for best results? As I'm trying to understand if you would need to 'customize' your swarm peripherals, amps, speaker wire, crossovers and any other hardware to work with the subs a customer may propose. Or if you can or cannot do such a thing? I'm asking these questions with complete respect and sincerity of what you do and have accomplished and am just curious?
Tim, it might surprise you to hear that the system with the best bass I've ever heard consisted of two subwoofers and that they were crossed over at 120. I was quite surprised at the crossover point, but there was no denying what I (and a number of other pretty serious enthusiasts heard).

There's more than one way to skin a cat. 
Tyray asked: "Can a customer use their own passive subwoofers of choice?"

You can totally use your subs of choice, active or passive. Here is the amplifier that I use to drive my passive subs, note that it has a single band of EQ and a switchable 25 Hz "bass boost" circuit, which may come in handy with sealed subs:

https://www.parts-express.com/dayton-audio-sa1000-subwoofer-amplifier-rack-mountable--300-811

Tyray: "Or do I have to use AudioKinesis designed passive speakers for best results?"

I think the subs I designed work well for this application, but they are NOT required for good results. I don’t like to make claims like "best results" because in this hobby there is always something better... I’ll only claim "best I know how to make at my price point given where I think the goal posts are."

Tyray: "As I’m trying to understand if you would need to ’customize’ your swarm peripherals, amps, speaker wire, crossovers and any other hardware to work with the subs a customer may propose."

I don’t really "do" custom Swarm systems wherein I don’t at least supply the passive subs, but it’s not rocket surgery. Briefly...

Spread your subs asymmetrically around the room, perhaps with one (but no more than one) in a corner, and bonus points if you can raise at least one sub up off the floor such that it is closer to the ceiling than to the floor.

(If you prefer, you can also use a symmetrical configuration - see Todd Welti’s "Subwoofers: Optimum Numbers and Locations" on Harman’s website.)

Any subs which are fairly far from the main speakers, you want their top ends to be rolled off fairly steeply no higher than 80 Hz, so they don’t betray their locations by passing audible upper bass/lower midrange.

I usually find that reversing the polarity of the sub farthest from the main speakers tends to improve the in-room smoothness, but in a very large or open-floorplan room the result may be deficient in the bottom octave.

If you don’t have test equipment, when setting the controls on your subwoofer amp(s) by ear, the sequence is: First set the level, then the frequency, then the phase. Cycle back through this sequence several times to fine-tune. Credit to master acoustician Jeff Hedback for teaching me what the proper sequence is.

Duke
With Subwoofers the moor the better it distributes and even out unbalances in rooms .the best sub on the market period at $1500
or 7nder is the new SVS 3000 SB it has the latest 50+ bit processor that monitors control the drivers movement, plus processing with a good app great heavy duty driver and at $995 delivered buy 2 and even get $100 off 13 inch driver that weighs over 25 lbs and goes to 18 hz ,it has a short long pole piece 
for low volume great control ,when you crank it up it uses the outer 
part ,no one else is doing this, the ultra is the flagship at $2500
with a 16 inch driver both are best in class and won a Tons of awards  free shipping, 45 day audition ,free return and refund if not 
totally happy. And a 5 year warranty I sold my $1600 JL Audio 
for the 3000 they are excellent l
big_greg:
"Tim, it might surprise you to hear that the system with the best bass I've ever heard consisted of two subwoofers and that they were crossed over at 120. I was quite surprised at the crossover point, but there was no denying what I (and a number of other pretty serious enthusiasts heard).

There's more than one way to skin a cat. "

Hello big_greg.

     As far as you, the readers and the authorities know, I stopped skinning cats years ago. Shhhh.
     I am surprised by your comment about the best bass you've experienced.  You're correct, I wasn't surprised that only 2 subs were utilized because I know very good bass quality is very attainable with 2 subs if you only require very good bass at a single designated listening position in the room.  Utilizing 4 subs in a distributed array typically further improves the bass quality, integration and it provides this high quality bass throughout the entire room, not just at a single 'sweet spot'.
     Just like you, I'm most surprised by the extremely high crossover frequency of 120 Hz, which is generally considered upper bass, is well above the 80 Hz threshold at which bass tones become localizable.  Most individuals should be easily able to discern that 120 Hz tones are originating from the 2 subs which normally negatively effects good imaging.
    My main speakers have rated bass extension down to 35Hz.  I run them full-range and have my 4 subs crossed over at 40 Hz.  I'm completely unable to localize any of these subs in my room, which is what's desired, but I am easily able to localize each of them as the crossover frequency is raised beyond about 80 Hz. This significantly and negatively effects the sound stage imaging in my room as expected.  
     I cannot explain why the very high 120 Hz crossover setting in your 2 sub audition didn't significantly and negatively effect the sound stage imaging in the room.  Can you?


 
  
Tim, the last time I talked about something like that having to do with cats my post was deleted by the mods, so I'll refrain.  I should have asked more about the why of the crossover setting.  It just came up in passing as we were heading out the door.  I'd like to get that guy to come over to my place and help me get my subs dialed in better once things return to whatever the new "normal" is.  I've tried a high crossover setting with my subs.  It didn't sound bad, but it bothered me that the sound was localized.  I could "hear" the two behind me.  In my friend's setup, I couldn't tell at all by listening where the subs were.  He had a lot of room treatment, so I'm assuming that helped.  His system sounded fantastic.