Opposed Subwoofer Design

Posted by: INANE

Opposed Subwoofer Design - 02/06/13 04:48 PM

Curious what folks/Axiom think about opposed subwoofer design in general. Where you have two drivers in a single box on opposite sides of each other.
Posted by: MarkSJohnson

Re: Opposed Subwoofer Design - 02/06/13 06:43 PM

Ummmm....They're opposed?
Posted by: turbo16v

Re: Opposed Subwoofer Design - 02/06/13 07:57 PM

The Seaton submersive is thought by many to be one of the best subwoofers available at any price. It's dual opposed.
Posted by: SirQuack

Re: Opposed Subwoofer Design - 02/06/13 08:08 PM

I heard an Epik Empire once, crazy performance. Almost got a few of them over Axiom, will always wonder.

http://www.epiksubwoofers.com/products.html
Posted by: jakewash

Re: Opposed Subwoofer Design - 02/06/13 09:15 PM

Wasn't the original Audiobytes sub an opposed driver system?
Posted by: pmbuko

Re: Opposed Subwoofer Design - 02/06/13 10:09 PM

Nope. The original Audiobyte sub (EPZero, which I have) is an isobaric sub.
Posted by: fredk

Re: Opposed Subwoofer Design - 02/06/13 10:44 PM

The design works just fine. I'm not sure that physics backs up the claim of vibration cancellation. I've heard it keeps the sub from jumping around if you are using two monster 18" drivers. grin
Posted by: MarkSJohnson

Re: Opposed Subwoofer Design - 02/07/13 05:16 AM

Originally Posted By: fredk
I've heard it keeps the sub from jumping around

What if I WANT them to
Jump around
Jump around
Jump around
Jump up Jump up and get down?
Posted by: Andrew

Re: Opposed Subwoofer Design - 02/09/13 12:06 PM

Originally Posted By: INANE
Curious what folks/Axiom think about opposed subwoofer design in general. Where you have two drivers in a single box on opposite sides of each other.


Ah...a topic near and dear to my heart. If I am not mistaken, Mirage produced the first commercial subwoofer with an opposed woofer design with the drivers operated in phase with one another. This first model was the BPSS-210 and was originally designed for use in systems with the first Mirage bipolar speakers, the M-1 and M-3. This was in the very early days of home theatre and most of the original subs were sold with 2-channel systems. The design benefits behind opposed driver subwoofers are improved room loading from the multiple drivers and an almost complete cancellation of cabinet vibration. These designs are not gimmicks, they most certainly result in improved performance when well designed. I believe the main reason that we don't see more of them on the market is that the second (or third) driver(s) add significantly to the cost. One thing to watch are designs claiming to have force cancelling drivers where one driver is actually a passive radiator. In this case there will be no benefit in terms of reducing cabinet vibration. Interestingly enough, as Ian and I have been working on design ideas for the "v4" series of subwoofers we have been discussing the possibility of one or two models incorporating a balanced or force cancelling driver configuration. As with everything we do the designs would be evaluated strictly based on their performance versus the current models. Now is as good a time as any to throw the question out there: Is this type of design something that would interest you? wink
Posted by: cohesion

Re: Opposed Subwoofer Design - 02/09/13 01:27 PM

Originally Posted By: Andrew
Originally Posted By: INANE
Curious what folks/Axiom think about opposed subwoofer design in general. Where you have two drivers in a single box on opposite sides of each other.


Ah...a topic near and dear to my heart. If I am not mistaken, Mirage produced the first commercial subwoofer with an opposed woofer design with the drivers operated in phase with one another. This first model was the BPSS-210 and was originally designed for use in systems with the first Mirage bipolar speakers, the M-1 and M-3. This was in the very early days of home theatre and most of the original subs were sold with 2-channel systems. The design benefits behind opposed driver subwoofers are improved room loading from the multiple drivers and an almost complete cancellation of cabinet vibration. These designs are not gimmicks, they most certainly result in improved performance when well designed. I believe the main reason that we don't see more of them on the market is that the second (or third) driver(s) add significantly to the cost. One thing to watch are designs claiming to have force cancelling drivers where one driver is actually a passive radiator. In this case there will be no benefit in terms of reducing cabinet vibration. Interestingly enough, as Ian and I have been working on design ideas for the "v4" series of subwoofers we have been discussing the possibility of one or two models incorporating a balanced or force cancelling driver configuration. As with everything we do the designs would be evaluated strictly based on their performance versus the current models. Now is as good a time as any to throw the question out there: Is this type of design something that would interest you? wink


Thanks Andrew for sharing a bit more about what you and Ian are currently considering for the v4 subs!

I for one am very interested in the new designs. I need a new sub now more than any other component! So how would a dual opposed sub be better than an EP800? Would it cost more?
Posted by: casey01

Re: Opposed Subwoofer Design - 02/09/13 01:50 PM

Originally Posted By: Andrew
Originally Posted By: INANE
Curious what folks/Axiom think about opposed subwoofer design in general. Where you have two drivers in a single box on opposite sides of each other.


Ah...a topic near and dear to my heart. If I am not mistaken, Mirage produced the first commercial subwoofer with an opposed woofer design with the drivers operated in phase with one another. This first model was the BPSS-210 and was originally designed for use in systems with the first Mirage bipolar speakers, the M-1 and M-3. This was in the very early days of home theatre and most of the original subs were sold with 2-channel systems. The design benefits behind opposed driver subwoofers are improved room loading from the multiple drivers and an almost complete cancellation of cabinet vibration. These designs are not gimmicks, they most certainly result in improved performance when well designed. I believe the main reason that we don't see more of them on the market is that the second (or third) driver(s) add significantly to the cost. One thing to watch are designs claiming to have force cancelling drivers where one driver is actually a passive radiator. In this case there will be no benefit in terms of reducing cabinet vibration. Interestingly enough, as Ian and I have been working on design ideas for the "v4" series of subwoofers we have been discussing the possibility of one or two models incorporating a balanced or force cancelling driver configuration. As with everything we do the designs would be evaluated strictly based on their performance versus the current models. Now is as good a time as any to throw the question out there: Is this type of design something that would interest you? wink


Andrew, you beat me to the punch on this one in stating that Mirage was probably the first to incorporate this type of design, a natural in their case working hand in hand with their enormous bipolar models you mentioned and they did sound very good. One thing you didn't mentioned when HT started to come in to vogue, Mirage designed and built an excellent crossover unit that worked beautifully in conjunction with any sub, an item somewhat ahead of its time.

The only passive radiators I have seen and heard in a few models were incorporated in to small powerful subwoofers to attempt to reinforce the bass in ultra small cabinets. Despite the claims of deep, powerful bass in a small package, I was never impressed with any of these overpriced designs and I think the marketplace has shown it.

When it comes to subwoofers, I have always believed that you can't really defy the laws of physics, the bigger the cabinet, the better, deeper AND louder the bass with less distortion. Since it will give somewhat more flexibility in placement and provided it is competitively priced, the bipolar design is one that Axiom should strongly consider for the future, forget the passive radiators.
Posted by: SirQuack

Re: Opposed Subwoofer Design - 02/09/13 02:24 PM

totally interested if affordable
Posted by: chesseroo

Re: Opposed Subwoofer Design - 02/09/13 03:00 PM

Originally Posted By: Andrew
Is this type of design something that would interest you? wink

And to that question i ask a question, which design idea would actually NOT interest the forum readers here?
Posted by: fredk

Re: Opposed Subwoofer Design - 02/09/13 08:35 PM

Originally Posted By: chesseroo
Originally Posted By: Andrew
Is this type of design something that would interest you? wink

And to that question i ask a question, which design idea would actually NOT interest the forum readers here?
I'm so glad you asked. I'm pretty sure not many would be interested in this idea:

... and I really don't want them to release something like this:


... because then CV will abandon his alligator pit and start digging for the new Axiom sub.
Posted by: fredk

Re: Opposed Subwoofer Design - 02/09/13 08:44 PM

Originally Posted By: casey01
The only passive radiators I have seen and heard in a few models were incorporated in to small powerful subwoofers to attempt to reinforce the bass in ultra small cabinets. Despite the claims of deep, powerful bass in a small package, I was never impressed with any of these overpriced designs and I think the marketplace has shown it.

When it comes to subwoofers, I have always believed that you can't really defy the laws of physics, the bigger the cabinet, the better, deeper AND louder the bass with less distortion. Since it will give somewhat more flexibility in placement and provided it is competitively priced, the bipolar design is one that Axiom should strongly consider for the future, forget the passive radiators.

Casey. My understanding of subwoofer design is that you use the passive radiator to eliminate the internal volume of a port (making the sub a little smaller) and to completely eliminate the issue of port chuffing. The cheating of physics in small commercial designs is probably a design compromise where the designer wants a smaller cabinet more than deeper bass and so reduces cabinet volume beyond just that which the port makes up.
Posted by: INANE

Re: Opposed Subwoofer Design - 02/10/13 02:17 AM

Originally Posted By: Andrew
Now is as good a time as any to throw the question out there: Is this type of design something that would interest you? wink


Well, ya laugh

I have been looking at the Epik subwoofers because their prices are relatively low. I've also been considering the DIY route again (all my subs have always been DIY). Regardless this design does intrigue me.
Posted by: cohesion

Re: Opposed Subwoofer Design - 02/10/13 07:13 PM

Originally Posted By: fredk
Originally Posted By: chesseroo
Originally Posted By: Andrew
Is this type of design something that would interest you? wink

And to that question i ask a question, which design idea would actually NOT interest the forum readers here?
I'm so glad you asked. I'm pretty sure not many would be interested in this idea:



Actually that one looks pretty good to me - but only if it comes with an Axiom logo instead of what's there!
Posted by: Boltron

Re: Opposed Subwoofer Design - 02/10/13 11:01 PM

I will be purchasing a second sub to replace a smaller polk soon I hope. I can't wait to see/hear whats in store. Size however is a constraint for me, I am hoping the next gen subs will not be bigger than the EP500 (or else the wife will notice ;))
Posted by: GregLee

Re: Opposed Subwoofer Design - 02/19/13 05:57 PM

Maybe this is like the Sony SA-WX700 "push-pull" sub? I think they're no longer made. They were inexpensive, and I bought one. Mine broke (as did many of them, I gather) after a year or so. I still have it sitting in a corner of my listening room, waiting for me to replace a condenser, in hopes that would bring it to life. I was pleased with it, while it worked, but I couldn't give you a good critique.
Posted by: INANE

Re: Opposed Subwoofer Design - 02/22/13 12:24 AM

Originally Posted By: GregLee
Maybe this is like the Sony SA-WX700 "push-pull" sub? I think they're no longer made. They were inexpensive, and I bought one. Mine broke (as did many of them, I gather) after a year or so. I still have it sitting in a corner of my listening room, waiting for me to replace a condenser, in hopes that would bring it to life. I was pleased with it, while it worked, but I couldn't give you a good critique.


What I'm talking about is not push-pull. That Sony resembles an isobaric design. In a dual opposed the drivers would be push-push.

I'm seriously considering buying a pair of inexpensive (aka cheap) drivers and building a very basic enclosure just to see what gotchas I might come across.
Posted by: rrlev

Re: Opposed Subwoofer Design - 02/22/13 01:24 PM

Andrew, don't know why your asking us ... (except perhaps to get us all excited).

I will, of course, be interested if it improves something without giving up something else. So if rearranging an EP800, can get something like better seat to seat performance using this design; i'm all ears (so to speak ... especially if the price stays the same). If it's more subtle, like less cabinet vibration, I'm interested and it's a selling point but ... it will be hard to get me to pay for it unless you can relate it a performance gain.
Posted by: cb919

Re: Opposed Subwoofer Design - 02/22/13 05:36 PM

I'd be very interested in this design as well. As others have said, I am curious what the real world advantage would be to this design? Is it similar output in a smaller package? Sonos has adopted this design in their subwoofer , but that is a niche product for Sonos owners. Plus they have oval 'racetrack' drivers to get the form factor they wanted.

I am excited to see what Axiom will come up with for new sub designs! Please keep us posted Andrew.
Posted by: CatBrat

Re: Opposed Subwoofer Design - 02/22/13 06:01 PM

Nope. I'm opposed.
Posted by: INANE

Re: Opposed Subwoofer Design - 02/22/13 06:09 PM

Originally Posted By: CatBrat
Nope. I'm opposed.


/shocked

shocked
Posted by: fredk

Re: Opposed Subwoofer Design - 02/22/13 06:21 PM

Originally Posted By: CatBrat
Nope. I'm opposed.

Soooo, you don't know if you're coming or going? You need to visit Dr. Doolittle.
Posted by: SBrown

Re: Opposed Subwoofer Design - 02/22/13 07:54 PM

I'm really interested what they have in store for us, I hope it is apposed.
Posted by: Adrian

Re: Opposed Subwoofer Design - 02/25/13 01:18 PM

I'd be interested in this type of sub and it's tehnical advantages over a single or dual driver (same baffle mount) from Andrew. I'd imagine sq would be the main benefit due to vibration cancellation, and driver protection would improve with the sealed/opposed configuration.