The Absolute Sound posts a video about a new product development from Magnepan, but...

@clio09: The KLH 9, another ESL I’ve never heard. I think that model never made it to the West Coast (in 1972 the leading high end shops were in the North, East, and South. Guys like Paul Heath in Philadelphia.).

When I discovered J. Gordon Holt and his Stereophile Magazine in 1972, he had double-KLH 9’s as one of four loudspeakers comprising his list of Class A Recommended Components. The others were the new Magneplanar Tympani T-I (in it’s revised incarnation, which improved the T-I’s high frequency extension), the Infinity Servo-Static 1 (which I did manage to hear, but at $2,000/pair---in 1972 that was lot of dough---were out of reach for me), and the Hartley Concert-Master. He had the Quad ESL in Class B.

Another ESL I was interested in was the Dayton-Wright, made in Canada. I went up to a new hi-end shop in Berkeley to give them a hearing, the shop owned and operated by David Fletcher, who later gaining notoriety as the designer of the Sumiko "The Arm" and the SOTA turntable. David struck me as an extremely intelligent fella, and when I couldn’t hear the Dayton-Wright (I don’t recall why he couldn’t demo the pair he had), I asked David about the Tympani’s (which were at the top of my list to audition). He was unusually candid when he said "I’m pushing the Dayton-Wrights." 😉

@clio09: I remember that Roger often extolled the virtues of the Acoustst panels themselves, but considered the transformers absolute junk. Do you have the only pair of Model 2’s he worked on?

By the way ESL fans, Roger advised me to cross-over my Quad 57’s (originals) to subs at 100Hz using 4th-order filters (24dB/octave), as he found the bass panels to be unacceptable below that frequency. He deplored resonances, whether electronic or acoustic.

Though I heard all the other Acoustats---including the 2+2 and 1+1---I never heard the Model X. The other electrostatic I desperately wanted the hear were the two Stax models, which JGH loved.

@andershammer: Is the Acoustat X model the one that included power amps? I think Roger Modjeski of Music Reference offered a mod for the amps.

@mwinkc: $4000 for the "X" upgrade to the MG2.71?! I’m very curious as to how Magnepan justifies that!

As a reminder, Eminent Technology already offers a planar-magnetic loudspeaker with a dipole woofer system, the LFT-8c. $4500, and the LFT-8b with a sealed monopole woofer is $3200, only $200 more than the MG1.7i. And unlike the single-ended operation of the MG1.7i, the LFT-8b and -8c are push-pull designs, with magnets on both sides of the Mylar diaphragm. The LFT-8 has a ribbon tweeter, operating from 10kHz up, with a single-pole high pass filter. I’m sure Danny Richie disapproves of that. 😉

Oh, a few more facts and I’ll shut the Hell up (yeah, sure 😊 ).

In the demonstrations of the prototype 30.7 For Condo’s, Wendell Diller was unequivocal and quite adamant that monopole subs (sealed and ported) "Do not work" (his words) with planar loudspeakers. And ya know, in a way the big Maggies (the older Tympani’s, the current 30.7) actually contain OB/Dipole subs---the huge bass panels of those models. They can reproduce (when braced) down to 30Hz. Nothing else I’ve heard makes the recordings I made (via small capsule condenser mics plugged directly into a Revox A77 Mk.3) of my Gretsch drumset with Paiste 602 cymbals sound as close to live as do big Maggies.

In his system at shows, Danny Richie employs a pair of the OB/Dipole Subs in the front of the room, a pair of sealed Rythmik F12G subs in the rear.

I neglected to mention that the Rythmik Audio plate amp that comes with the OB/Dipole Sub contains a dipole cancellation network, and the Rythmik servo-feedback system enables the sub to reproduce 20Hz at reasonably loud levels. The sound of an open baffle sub is quite different from a "normal" sub. It in fact sounds very much like that produced by a magnetic-planar panel. I know that because I have a pair of Magnepan Tympani T-IVa loudspeakers, the precursor to the 30.7.  

Another "fairly" good engineer who "believed" in and offered an OB/Dipole sub was Siegfried Linkwitz, who was no fool.

@mijostyn: I guess you haven’t heard who has been working on prototype dipole subs for a few years now. Wendell Diller and Magnepan. The proposed upcoming model that will pair magnetic-planar midrange/tweeter panels with dipole subs has been humorously nicknamed "The 30.7 For Condos" by Wendell.

I HAVE been comparing open baffle/dipole and sealed subs for a few years now; The OB/Dipole that Brian Ding of Rythmik Audio and Danny Richie of GR Research developed in a collaboration, and the F15HP from Rythmik Audio. I’m not alone in doing so. Of course the Rythmik Audio/GR Research OB/Dipole Sub is no amateur experiment. Brian Ding of Rythmik Audio holds a PhD in electrical engineering, and is a very clever fellow, his servo-feedback design being patented.

Danny Richie’s GR Research system (which included both the OB/Dipole Sub and Rythmik F12G sealed subs) was awarded best sound at a couple of RMAF’s.

People, please don’t force me to sound like a pitchman for GR Research and Rythmik Audio. If you got your facts straight I wouldn’t feel compelled to do this.

@cey: No he didn't.

By the way, one very popular after-market product for Maggies are the stands Grant Mye up in Canada makes for them. While many Maggie owners are perfectly content with the bases supplied by Magnepan, there are some owners who desire to maximize the potential of their Maggies. The Maggie frames---made of MDF---are to an extent prone to flexing. Go ahead, grab a Maggie frame with one hand on each top corner, and try to twist it. You will be successful.

Are the testimonials from Mye stand customers the result of self-induced delusion? Are the improvements claimed to be heard by those who rebuild with better parts their speaker cross-overs (not just Maggies, the cross-overs in most speakers are junk. Watch the GR Research YouTube videos, wherein Danny Richie shows you what they're made of. It's not pretty.) also delusion? If you haven’t tried it yourself, your opinion is pure conjecture.

Just as most owners of Chevy small block V-8 engines are satisfied with it’s power (250HP), there are those automobile enthusiasts who aren’t, and they bolt a Whipple blower onto their engine for an easy increase of 100HP. After-market products for built-to-a-price-point hi-fi products are made for audiophile enthusiasts, not passive consumers.

Yeah, after fifty years at Magnepan Wendell Diller finally decided to sell out. I wonder what took him so long? 😉

Preliminary reports suggest the "X" versions of some Magnepan models---certainly the 3.7i, perhaps the 20.7i and even 30.7 as well---will simply be exactly the same as current versions, but with binding posts for the individual drivers in place of the single pair of binding posts, and without the internal cross-over. The consumer will then be free to use whatever x/o they desire. That’s why Tom Martin of TAS coined the term "Open Architecture" for this development.

It could be that the X versions will cost no more than the stock versions. Magnepan will be saving the cost of their x/o, with the cost of extra binding posts being minimal. This is gonna be interesting. For those who are interested, that is. Like everything else in life, it’s not for everyone. It’s like bolting a blower on your Chevy small block.

Excellent @mwinkc! What say ye now, @secretguy? 😉

It’s very easy to improve on some of the stock Maggie x/o parts. You can simply bypass the fuse block, and the holes in the x/o plate for the stock Magnepan speaker binding posts are the same size many other posts require. I installed Cardas silver/rhodium plated copper posts, but Ric’s endorsement of the WBT Nextgen posts has me curious. I have WBT Nextgen RCA plugs on one of my tone arms (a Helius Omega Silver), KLE Innovations Absolute Harmony on another (Trans-Fi Terminator), both having continuous silver wiring from cartridge clips to RCA plugs. I may be a little obsessive, but Ric’s way worse. 😊

Ric---Thanks for the heads up on the Rich Hollis info. I know Rich has had interaction with Danny Richie for years. I used to read the AudioCircle Forums, don’t know why I stopped.

The OB subs pictured in the TAS video are four of the GR Research 8" woofer models per channel. They probably put out about as much bass as do two of the 12" woofers. Are 8" woofers "faster" than 12" woofers? Danny says (as does Brian Ding of Rythmik Audio, with whom he collaborated on the OB Sub) in this case no. It has to do not only with the moving mass of the driver cone, but also the the motor (magnet) strength, the "settling time" of the cone, etc. The servo-feedback design of the Rythmik woofers/plate amp combo is another factor in how fast the OB Sub sounds. "Stops on a dime". 😉

Brian Ding offers the 8" woofer for instalations where a higher x/o frequency is desired. The 8" can be used up to a higher frequency than the 12", though the 300Hz limit on the 12" is already much higher than is the case with "normal" subs.

That Maggies sound as good as they do in spite of their crappy x/o parts is a testament to the quality of Jim Winey’s basic magnetic-planar driver (and ribbon tweeter) design. Hard-core Maggie enthusiasts have been upgrading the cross-overs in their speakers for decades.

I bought my first pair of Maggies---their original model, the Tympani T-I---in 1973, and now have a pair of Tympani T-IVa. I don’t run them with the stock cross-over (sorry, it’s junk. Unless you like the sound of iron core inductors, steel parts in the signal path, etc.), using instead a First Watt B4 x/o, designed and built by Nelson Pass. It’s an all-discrete design, using high quality resistors to provide an amazing number of filter x/o frequencies (from 25Hz to 6275Hz, in 25Hz increments) and slopes (1st, 2nd, 3rd, and 4th order---6, 12, 18, 24db/octave)..

Speaking of improving: It was Winey’s magnetic-planar driver that inspired Bruce Thigpen of Eminent Technology to develop his LFT driver. He saw that the Maggie drivers were single ended---magnets on only one side of the Mylar diaphragm, and thought "Why not make a planar-magnetic driver that is a balanced, push-pull (magnets on both sides of the Mylar) design?" So he did just that, and named it the Linear Field Transducer, or LFT.

More details on the upcoming "super" Maggies: The cross-over will be active, just as is the x/o provided with the Linkwitz LX541.4. It is inserted in the chain in between the pre-amp/sources and the three required power amps (again, just as with the LX521). The x/o Danny Richie offers is of course passive, receiving it’s signal from a single power amp. Two very different architectures.