[Edgar77]

I admit Danny's H-frame and W-frame subs look good. And a couple of drivers look obviously better than just one or two. But how many are really needed?

I remember a couple of years ago (or maybe many years ago) people used one subwoofer with one driver - possibly somewhere in the corner.
Now it seem many people here use H-frames with two drivers. And not just one but two of them.
And some people use even two triple subwoofers.
Is that not total overkill?

As far as I understand if subwoofer really "only" do the jobs which they are supposed to do then they are used for frequencies below about 80Hz. And as far as I understand people can't locate those frequency. I read nobody should be able to locate the subs. The idea is that one or more subwoofers make the "normal" speakers sound better, more base. The listener should think all frequencies, even the real low frequencies, come from the stereo speakers and not from the subs.

So coming back to the beginning: Does it really make sense and/or is necessary to have 4 or even 6 subwoofer drivers? Or should one or two drivers in one frame be enough?
I am sure this also depends on the speakers. In this scenario let's think about a combination with NX-Oticas or NX-Studio or something like that.

[S Clark]

It depends on room size, volume level, and the degree of realism you are looking for.  I have one OB dual 12 servo between two X Static speakers-- in a small/mid size room.  In my big room I'd need at least a pair.  But my big room has speakers that really don't need subs at all. 

[Tyson]

OB subs work best in pairs and when placed near a speaker.  Box subs work well as a single sub and placed in a corner.  Different designs have different placement needs. 

[corndog71]

Subs used to be pretty simple.  Driver, Amp, and box.  Too often they were boomy and just barely adequate for the job.  I mean unless you want boomy bass.

With Danny and Brian from Rythmik you get servo technology.  It’s better.  Faster. 
Until you’ve heard what Danny’s designs can do, you don’t know what you’re missing.

I started with the single sealed servo sub.  It performed like no other sub I’d heard before.  It took me a while to get it dialed in but once that happened it blended seamlessly with my X-Statiks.

I wanted the dual open baffle servo subs as soon as Danny posted about them.  It took years before I could afford them but they were absolutely worth it.  They might look like overkill but they’re really not.

And everyone who has heard the duals and the triples say the latter are even better.

[Edgar77]

Subs used to be pretty simple.  Driver, Amp, and box.  Too often they were boomy and just barely adequate for the job.  I mean unless you want boomy bass.

With Danny and Brian from Rythmik you get servo technology.  It’s better.  Faster. 
Until you’ve heard what Danny’s designs can do, you don’t know what you’re missing.

I started with the single sealed servo sub.  It performed like no other sub I’d heard before.  It took me a while to get it dialed in but once that happened it blended seamlessly with my X-Statiks.

I wanted the dual open baffle servo subs as soon as Danny posted about them.  It took years before I could afford them but they were absolutely worth it.  They might look like overkill but they’re really not.

And everyone who has heard the duals and the triples say the latter are even better.

Thanks for the info. To be sure I understand that right: You had one sealed servo sub which you thought was good. And then you switched to one or two of the dual open baffle servo subs?
And do you consider upgrading to (two?) triple subs?

As far as I know the servo subs can be dialed in to match perfectly with any speakers. So I would guess you need only more of them if they don't produce enough power. So I ask myself what do "you" want to play at which volume which needs more than 4 servo driven 12" subwoofers?

[ThePriest]

Bear in mind that the OB subs from GR are more than just subs. They can play up to 2-300 Hz (which can be needed, especially if the rest of your system is also OB), so they have a wider range of use.
I have gone from two dual subs to two triple. The sound quality did not change much, which is to be expected, but the way they fill the room has changed a lot for the better.
It just feels so effortless and natural.

/The Priest

[corndog71]

My single sub is in a different room than the OB subs.

[Edgar77]

Bear in mind that the OB subs from GR are more than just subs. They can play up to 2-300 Hz (which can be needed, especially if the rest of your system is also OB), so they have a wider range of use.
I have gone from two dual subs to two triple. The sound quality did not change much, which is to be expected, but the way they fill the room has changed a lot for the better.
It just feels so effortless and natural.

/The Priest

Thanks

I understand that some speakers don't play low frequencies, lets say 120 Hz, and then I guess it's necessary to have subwoofers on both sides because the listener will be able to hear where the sound comes from.

As far as I know (I read it somewhere here) anything below 80 Hz can't be located by humans.
For the NX-Otica Danny writes on his website: "The -3db of the bottom end will vary from room to room and can be as low as mid 40's or as high as high 70's."
So I guess in combination with the NX-Oticas several subs are not necessary to make sure the bass comes from the right direction because the subs will only play frequencies below 80Hz.
So in that case with the NX-Oticas: Is one sub, maybe one H-frame with 2 or even 3 drivers "good enough"? Or would two H-frames produce a better sound?

Speaking about the NX-Oticas means of course a couple of thousand USD, so one or two more drivers won't really make a big price difference. For me this is more a question of understanding the principle. Is there a point of adding more if there is already a lot?

[Early B.]

As far as I know (I read it somewhere here) anything below 80 Hz can't be located by humans.

That's one of the biggest lies in audio. It's simple to disprove -- get a sub, set it anywhere in the room, and there's a 99% chance you're gonna hear where the bass is coming from. Doesn't matter where you set the crossover. Same holds true with any speaker.

With subs, more is better. I have three dual servo subs in a modest 13x20x8 room. If I had the space, I'd build a fourth sub. Subs provide much more than bass. Subs form the foundation of your music, so they improve soundstage, imaging,... everything, including the highs.

You ain't gonna fully appreciate or understand the value of multiple OB servo subs until you do it. 

 

[corndog71]

Forgot to mention that the open baffle subs load the room differently than sealed or ported box subs.  They also sound better away from the walls.  That’s another reason for multiple drivers. 

[Captainhemo]

We send out kits from duals to quads  and typically they are in pairs.  We've owned and heard them all as well  and  tell you  remember this....     in  moderately sized room, adding more  drivers is not necessary for SPL,  dual play plenty loud enough in  2stereo h-frames but, adding more drivers to reach those same SPL's will reduce the workload of each woofer.  Now, the servo subs are already extremely quick but,  when the workload of each driver is reduced, the settling time is reduced even further.   You  are also adding surface areawhich will help increase impact  aeven at lower listening levels....

With regards to stereo pairs,  yes,  it makes a huge difference.  A single  h-frame  will work  , and it will work well but, add that 2nd tower and run  them in stero and you wil be  amazed at what happends

jay

[Danny Richie]

Lots of good answers here already. But I would add that when going to triples or a stack of six per side then each woofer moves less to reach the same SPL levels. So there is less stored energy and even faster settling times. So even at the same SPL levels the use of more woofers does have performance advantages.

[Captainhemo]

We've also got a go between the  triples and  6 stacks, here's a shot showing   one of our duals, triples, and quads  with different  amounts  of customization


jay

[VinceT]

I have a question regarding OB subs if the OP doesn't mind and I think could be relative to the discussion since we are talking about OB subs and using more versus less for better effect. I noticed in most of the videos and pictures of the NX series speakers, the placement of most of the larger triple/quads OB subs, the subs are usually outside the mains and slightly behind. I assume there is some science to that placement (probably because that's where it sounds the best) besides just aesthetics. If someone was wanting to add more servo subs to their set up, perhaps this should be something to take into consideration for the optimal placement and performance. You can stack a NX-Studio, NX-MTM, Wedgie etc. on a dual servo sub. When we get into the triples and quads OB subs, it seems the placement is different than just putting a servo sub next to the mains.

[Captainhemo]

Yes, with the NX Otica/Treme and  Studio's,  you can position  the  sub  towers outboard as the c/o  frequency is still relatively  low....  when you  get  to the MTM, it  staarts to move  up so  you  want to   keep things  aligned.....  now,  when you  get into the Super 7/Super mini, the c/o frequency becomes even higherso alignment with the OB subs is even   more important