The Shure V15 V with a Jico SAS/B stylus VS The Soundsmith Hyperion MR and Lyra Atlas SL

@mijostyn 

"Dipole subs do not work well, I have built and tested them. No matter how heavy you make them they shake and the cancellation effects along with room modes create wild frequency response aberrations."

Plenty of speakers use dynamic drivers mounted back to back, usually with their cages rigidly fixed together. Newton's Law of action and reaction ensure that dynamic forces exactly cancel.  One example is the sideways facing woofers in KEF's Blade, which is designed to act as a point source, but unfortunately is out of my price range!

There is dipolar and there is bipolar.  The difference is important.  In one case, where we are talking about two subwoofers mounted into opposite sides of a cabinet, the rear or opposite side firing woofer will cancel cabinet movement that might have been induced by a single subwoofer.  In the other case, the cabinet will wobble because the two subwoofers are taking turns rocking it back and forth, because they are 180 degrees out of phase.  I always forget the semantic distinction, but I'll stick my neck out.  In a dipolar subwoofer, the two woofers are out of phase with each other, which is undesirable also because it results in phase cancellation. In a bipolar subwoofer, the two woofers are in phase.  In that case, the motion of the two drivers on opposite sides of the cabinet cancel each other out, and there is also no phase cancellation. So bipolar subwoofer good. Dipolar subwoofer not so good.

@bdp24 Roger was a smart guy. 100 Hz is right. The only problem was he only had analog filters to use and 24 dB/oct or 4th order was the steepest he could go without penalty but it is too slow and you will get subwoofer coming through in the midrange. At 100 Hz the slowest filter you can use is 8th order or 48 dB/oct and you can only do that cleanly in the digital realm. I have been using dipole speakers of one sort or another exclusively since 1978. I have been using subwoofers since 1978 and not able to find a satisfactory commercial subwoofer I started building my own somewhere around 1990. You might want to look at the link below. Just so we get this straight. Dipole subwoofers will make bass, real crappy bass. The problem for most people is that bass is difficult to evaluate especially by ear because a lot of it you do not hear, you feel it. After decades of measuring subwoofers I know what low bass should sound and feel like. You would too if you had been studying the problem for 30 some odd years. 

@richardbrand First of all what you are talking about is not a dipole, but a bipole and in that regard you are speaking to the choir. You might take a look here  https://imgur.com/gallery/building-resonance-free-subwoofers-dOTF3cS I happen to think the KEF Blade is a fine sounding loudspeaker, just odd looking.

@lewm The problem with stacking 57s is an 8 foot Sound Labs. You get a full range line source that is indestructible with a much better dispersion pattern. If I were operating on a shoe string I would look for a pair of used Acoustat 2+2s or even better 3+3s. 

@rauliruegas I was wondering when you were going to turn up. I think inferior is a little too strong, but of all the cartridges that were available I'm sure there were better. Before MC my last high output cartridges were B+Os before that were Stantons and Pickerings. I'd have to go way back to trip over a V15. Call it nostalgia or just the desire to fart around. Back then my system was not remotely near what it is today. So, it is fun to hear what we were listening to back then. Now, What cartridge is mounted in your turntable at this moment??

@mijostyn

I did not mention dipole nor bipole! The Quad ESL-63 was called FRED as it is a Full Range Electrostatic Dipole - the rearward bass radiation is out of phase, since it comes from the same plane as the forward bass. FRED is logically a single driver but is manufactured as four adjoining panels.  The ESL 2905 has two additional bass panels, making four bass panels per speaker.

The Gradient subwoofer designed for the ESL-63 had one forward and one rear facing driver, but they were offset, not co-linear. The Duntech Thor had a single driver and had to be spiked to the floor to provide a semblance of stability for the ESL-63 it piggy-backed.

It makes sense to stack ESL 57 speakers vertically, but not the ESL-63 and later models. That would have introduced another point source to cause cancellation and reinforcement interferences! But if one could align them so the apparent sources one foot behind the plane of each speaker were in the same spot, you would get a bit more volume. You might even manage three or four aligned to that point source ... thereby creating a true Bipole from equal Dipoles.

@lewm: If you want, take a look at the dipole woofer system in the Linkwitz LX521, or go onto the GR Research website, where you can see the dipole sub Danny Richie and Brian Ding of Rythmik Audio co-designed.

Siegfried’s dipole woofer is a W (or M, same thing) dipole frame, each woofer mounted on it’s own baffle, the baffles mounted in the frame 90 degrees offset from one another. In the GR Research/Rythmik dipole sub, the woofers can be mounted in M/W frame fashion, or in an H-frame, the latter more common. In an H-frame, the woofers (two or three, the user’s choice) can be mounted facing 180 reversed from each other (one cone facing the listener, the other with the rear of the cone facing the listener), or all facing forward. What makes it a dipole woofer system is not how the woofers are mounted in regard to each other, but that the output from both the front and back of the woofer propagates into the room, the front and back waves being 180 degrees apart. In fact, you can build an ob/dipole woofer system using just one woofer.

Yes, those front and rear waves---being of opposite polarity---meet on both sides of the dipole frame, with resulting dipole cancellation. A loss of output is therefore inherent in the ob/dipole sub. There’s no free lunch! But once you’ve heard an ob/dipole sub, you’ll know why people are willing to accept that design penalty in exchange for the sound quality produced by the sub.

For many years, I considered the sound QUALITY produced by the big Magnepan woofer panels (two of the panels in the 3-panel Tympani models, and the current MG30.7) to be the best reproduction of low frequencies I had ever heard (Harry Pearson agreed with me). Well, the GRR/Rythmik OB/Dipole woofer system sounds very similar to the Maggies. Brain Ding characterizes it as sounding "lean". The question is: is it lean, or are "normal" woofers "fat"? The ob/dipole sub reproducing an upright bass (or the lower registers of a grand piano) has to be heard to be believed! The "texture" of the fingers plucking the bass strings is clearly audible, with no added "weight" or "pluminess."

To offset the dipole cancellation, Brian Ding installs a dipole cancellation compensation circuit into the plate amp that comes with the OB/dipole sub kit. That of course means the power amp must provide more power than it would sans the compensation circuit. Power is cheap, and the woofers used are pretty sensitive/efficient. The sub also features Ding’s patented servo-feedback control of the woofers, which is what drew Danny Richie to Rythmik Audio. Danny was already marketing an ob/dipole woofer, and the idea of mating it with servo-feedback sounded like an idea worth exploring. It was.

I’ve owned servo-feedback woofers mated with planar loudspeakers before---the Infinity RS-1b, and this sub is a whole ’nother matter. State-Of-The-Art reproduction of low frequencies! Audiogon member @jaytor has the GR Research/Rythmik woofer system, with four woofers per side (left and right channels). Crappy bass? Uh, no.