[Davey]

"Bi-polar" is different than "di-polar."  We probably should agree on basic definitions before venturing further. 

Bipolar implies the rear radiation is the same polarity as the front.  (The system is a pressure source.)
No interference nulls at 90 degrees.  Ideally a completely spherical radiation pattern.  (Omni-polar.)

Example, the Epik subwoofers are bi-polar......effectively omni-polar in their designed frequency range.
http://www.epiksubwoofers.com/legend.html

Dipolar implies the rear radiation is the opposite polarity as the front.  (The system is a velocity source.)  Strong interference nulls at 90 degrees.  Ideally like two spherical sources touching each other but operating in opposite polarity.  (One getting bigger while the other gets smaller and vice-versa.)  (Di-polar.)

Get inside an Epik subwoofer and reverse the connections on one woofer and you would have a dipolar source.

Cheers,

Dave.

[Russell Dawkins]

If a closed box is omnipolar, you can't expect an open driver to be *less* omnipolar.

At the frequencies involved, unless the baffle is huge, every driver will radiate omni-directionally. If you don't put a box behind the woofer, you'll simply have a 180-degree-out-of-phase second driver that is the back of the cone.

I think terms are being misapplied here. Omnipolar is being used to mean omnidirectional. A closed box, a "bipole" box or a surface mounted "infinite baffle" is an omnidirectional monopole in the bass regions. I say omnidirectional knowing that radiation is in fact hemispheric for most subs.
 

[AlliumPorrum]

Is there anyone who has heard both Peerless SLS 12" and GR Research 12" in dipole setup? Would be nice to hear some impressions and comments on main differences..?

[AlliumPorrum]

Or how about these AE's, any experiences on them: http://www.aespeakers.com/drivers.php?driver_id=32 ??

15"'s would certainly move more air than 12"'s. And on the other hand, I'm not sure if servo gives any benefit if there's 4 drivers per side, since the driver's movement is quite minimal.

[earwaxxer]

I have found that with the maggies, the sub needs to be placed close to the listening position. That way you can tune the sub to the 'speed' of the maggies. Get a good snappy 12" with plenty of power behind it. I built my own.

[Davey]

Or how about these AE's, any experiences on them :http://www.aespeakers.com/drivers.php?driver_id=32 ??

15"'s would certainly move more air than 12"'s. And on the other hand, I'm not sure if servo gives any benefit if there's 4 drivers per side, since the driver's movement is quite minimal.

It's more about the implementation than it is the driver.  If the driver has good linear travel and does so with minimal aerodynamic noise it's going to work fine.  All other parameters can be adjusted electronically.

Cheers,

Dave.

[AlliumPorrum]

It's more about the implementation than it is the driver.  If the driver has good linear travel and does so with minimal aerodynamic noise it's going to work fine.  All other parameters can be adjusted electronically.

Cheers,

Dave.

Thanks for your comment, Davey! Can you (or anyone) recommend some fairly priced 15" drivers that "has good linear travel and does so with minimal aerodynamic noise"? AE's might be good, but they also are quite expensive.

[Danny Richie]

Is there anyone who has heard both Peerless SLS 12" and GR Research 12" in dipole setup? Would be nice to hear some impressions and comments on main differences..?

Yep, I have heard both. And they are not very comparable. I can answer all the rest of your questions as well but I always get frowned upon for answering questions like this outside of the GR Research circle. Feel free to post those question in our circle.

[Davey]

Thanks for your comment, Davey! Can you (or anyone) recommend some fairly priced 15" drivers that "has good linear travel and does so with minimal aerodynamic noise"? AE's might be good, but they also are quite expensive.

Can you confirm you're asking about the Peerless SLS driver and not the XLS driver?  Big difference there. 

Dave.

[AlliumPorrum]

Can you confirm you're asking about the Peerless SLS driver and not the XLS driver?  Big difference there. 

Dave.

Yes, I was asking about SLS, since I've understood that it's better option for dipole setup.

[AlliumPorrum]

Yep, I have heard both. And they are not very comparable. I can answer all the rest of your questions as well but I always get frowned upon for answering questions like this outside of the GR Research circle. Feel free to post those question in our circle.

Danny, please feel free to comment on this subject; I wouldn't want to start many discussions of same object.

Over all, all comments on best possible 12" -18" drivers for 20-200hz dipole setup are more than appreciated! Main options now are Peerless SLS, GR Research, and AE Dipole15.

[Davey]

Yes, I was asking about SLS, since I've understood that it's better option for dipole setup.

I don't know about that.    It's not really a sub-woofer per se, and has limited Xmax for this type of application.  The GR and AE drivers (and many others) are probably much better suited.

A nice driver that I've used before (that doesn't cost and arm and leg) is the Dayton 315HF 8-ohm.
http://www.parts-express.com/pe/showdetl.cfm?partnumber=295-445

You probably should use two drivers per side in all applications since this allows to operate one in reverse polarity to reduce even-order distortion.  In that case, maybe a 10" driver becomes a preferred choice.

Cheers,

Dave.

[Danny Richie]

Danny, please feel free to comment on this subject; I wouldn't want to start many discussions of same object.

Over all, all comments on best possible 12" -18" drivers for 20-200hz dipole setup are more than appreciated! Main options now are Peerless SLS, GR Research, and AE Dipole15.

Yeah, but you are asking me to comment on my own product compared to other options that aren't even comparable. As soon as I lay out the differences I will be accused of using this circle to sell my own products. It has happened before.

Please let me rephrase your question.

You are looking for a new car with all out performance and handling. Your main options have been narrowed down to a Chevorlet Suburban, a Ford Expedition, or the Chevorlet ZR-1 Corvette.

Two have high moving mass that hinders acceleration and the high level of wind resistance due to the large surface area also really limits acceleration. The high moving mass also makes them difficult to stop especially at high speed. They are just not very agile vehicles. The third choice has less moving mass. So acceleration is great, and with less moving mass it makes it much easier to stop. More importantly though is that the huge carbon fiber brakes brings it to a stop much quicker than the others. It is really not a comparison really... 

[Davey]

I think where you run into trouble is when plugging your own products at the expense of others, and posting incorrect technical information.
I believe the Circle Manufacturers/Owners should have the ability to post/moderate with impunity......in their own forums.  However, when you venture outside, guys like me might ask those pesky questions. 

I think what we're talking about here is pulling a 27' boat on a trailer.  In that sense, the Corvette is not the best option.

Cheers,

Dave.

[Danny Richie]

I can however give you some direction on your topic that is unrelated to the woofers, but in regards to what you posted about the system.

Davey called the DEQX a silly gadget, and that is not too far from the truth to some degree. It is a good learning tool and is an interesting novelty. It is also not bad for use in an entry level or lower mid-fi system. But if you are really looking to move up the ladder then I would recommend avoiding those things.

The quality level of the DAC's used are not great. You are really bottle necked there. The DEQX is better than similar products from Behringer, or the Mini DSP product, but still a long ways away from most high end DAC's.

Also, the room correction in reality doesn't work. I could go on and on with the reasons it does not work. It can be somewhat useful in the ranges below 200Hz to control the bass levels but beyond that it should not be used as room control. There are also better ways to control bass levels too. 

I'd run the Maggies full range or use an in line filter in the interconnect path to roll off the lows. Then control the subs with their own control system to balance the response. Then put that DEQX money into a really good DAC and room treatments instead. You'll be glad you did.

[Danny Richie]

Davey, I don't post incorrect technical information about my products.

Seems like you also made those accusations once before regarding a crossover quality comparison demo using a Behringer speaker that I sent around. So I sent it to you, and you then (somewhat reluctantly) confirmed my measured data was just as I said it was. You even seemed a little bit upset over it as if you were really hoping to catch me in some type of a lie. I don't lie or post incorrect technical data.

And I don't think this guy is interesting in pulling a boat. He is looking for performance.

[Davey]

The Behringer speaker issue was not an objective comparison, but a subjective one.  I confirmed you had modified the speakers correctly (which you did) after I had to repair one for poor workmanship.  At that point it became a subjective evaluation and there is no correct or incorrect in that scenario.

As most folks who are non-politicians should know....lying and ignorance are two different things.    I've never accused you of lying.

Whether this is a boat pulling exercise or lapping the Nurburgring is a debatable subject.    In either case an analogy of this sort is somewhat silly.

Dave.

[AlliumPorrum]

Yeah, but you are asking me to comment on my own product compared to other options that aren't even comparable. As soon as I lay out the differences I will be accused of using this circle to sell my own products. It has happened before.

Oh ok, I did not know that they are "your" products. I surely understand your point.

So, let's not compare them to any other option, but just solve few issues I don't understand yet:

- Many have said (also on this forum) that 2 GR's per side would be more than enough in dipole setup. On the other hand, it is also often said that due the acoustic realities, even 4 x 12" is not gonna give very strong bass in dipole and at least 15's or 18's should be used to get real punch on dynamic music. What's your comment on this? Can GR's really give so much more punch that you can use half less of them? If, why?
- If I would use 4 GR's per side, the movement of drivers with normal listening levels should be quite minimal. And of course, that is a good thing from sound quality point of view. But doesn't this make servo functionality quite useless, compared to "normal" 1 driver subwoofer setup where driver moves a lot?

[lowtech]

I don't post incorrect technical information about my products.

So true.  You also post incorrect technical information about other manufacturer's products too.  Case in point, your diatribe about the DEQX in this thread.  It makes you look bad in the eyes of us who know better.

[AlliumPorrum]

Davey called the DEQX a silly gadget, and that is not too far from the truth to some degree. It is a good learning tool and is an interesting novelty. It is also not bad for use in an entry level or lower mid-fi system. But if you are really looking to move up the ladder then I would recommend avoiding those things.

The quality level of the DAC's used are not great. You are really bottle necked there. The DEQX is better than similar products from Behringer, or the Mini DSP product, but still a long ways away from most high end DAC's.

Also, the room correction in reality doesn't work. I could go on and on with the reasons it does not work. It can be somewhat useful in the ranges below 200Hz to control the bass levels but beyond that it should not be used as room control. There are also better ways to control bass levels too. 

I'd run the Maggies full range or use an in line filter in the interconnect path to roll off the lows. Then control the subs with their own control system to balance the response. Then put that DEQX money into a really good DAC and room treatments instead. You'll be glad you did.

Do you Danny have personal experience on these DEQX limitations? Which DEQX model was it? Could you please give a bit more detail on your setup; was it used on fully active setup with it's own digital crossovers, with what kind of drivers, etc?