The Absolute Sound posts a video about a new product development from Magnepan, but...
...fails to give any mention of the impetus for the development, for which Tom Martin has coined the term "Open Architecture". Here’s the full story:
Danny Richie of GR Research offers this service to his customers: Send him a loudspeaker you want him to evaluate, and he will put it through all his tests at no charge. He takes measurements of frequency response (on and off axis), cross-over characteristics (and the quality of the cross-over parts), individual driver responses, a spectrogram/waterfall plot, evidence of comb-filtering, impedance, sensitivity, etc. He evaluates any failings he finds, to see if he can develop measures to remedy those failings. Danny is a well-known expert at cross-over design, and if he feels the loudspeaker has the required potential he puts together one to "fix" the failings he finds in the speakers sent to him, selling the x/o in DIY kit form.
Over a year ago he received a Magnepan MG3.7i for evaluation, and ran it though his full battery of tests. In the video he posted on YouTube (see below), he describes his findings on that model Magnepan. He came up with a major redesign of the cross-over, to eliminate what he considers the MG3.7i’s failings. Finding fault in the measured frequency response of Magnepans is not new, but before dismissing what I just wrote, consider watching the video.
What he found was that the Magnepan cross-over slopes results in the three drivers (bass, midrange, tweeter) over-lapping each other, reproducing the same frequencies at the top (bass driver), top and bottom (midrange driver), and bottom (tweeter) of their ranges. That can cause comb-filtering, which is exactly what Richie found in his measurements of the MG3.7i. A lot of it. That filtering wreaked havoc on the response of the speaker, with lots of phase cancellation occurring due to the same frequency reaching the listening position from different drivers at different times (the definition of comb filtering).
Danny also found the cross-over to be comprised of absolute junk parts---push-on connectors, steel nuts and fuse assembly, electrolytic capacitor, iron-core inductor, etc. But THAT was already well known about Maggie cross-overs, with many after-market products offered to replace the stock parts.
So Danny created a new cross-over, which you will hear about in his video. What I want to highlight here is that he made a new cross-over plate to install in place of the stock one, but that plate merely holding three sets of connectors for the three drivers. Those inputs are fed from a new, separate x/o box, with all new x/o filters designed to---amongst other things---eliminate the comb-filtering, allowing the three drivers to create a beautiful frequency response. Danny suggests anyone considering the purchase of a pair of the MG3.7i to ask Magnepan if they are willing to make a pair without a x/o, in it’s place three jacks connected directly to the three drivers.
In his video, Danny also mentions how his GR Research/Rythmik Audio Open Baffle/Dipole Sub makes a great partner for use with the MG3.7i, or any other dipole planar for that matter. I’ve been touting that combo for years here on Audiogon.
So, I see the heading of the TAS video (posted below, if all goes well), and start watching it. One of the first pics I see is a pair of MG1.7i, with three sets of jacks where there is normally those crappy Magnepan speaker cable binding posts! I guess Magnepan has also watched Danny’s video 😉. On top of that, standing next to the MG1.7i’s are open baffle/dipole woofers!
Magnepan has been talking about offering an OB/Dipole sub for use with their planars for several years now, but there is already a dipole planar-magnetic loudspeaker with integral dipole (though not open baffle) woofers---the Eminent Technology LFT-8c. One can also add a pair of the GR Research OB/Dipole subs to the ET LFT-8b, using the OB sub in place of the LFT-8b’s monopole woofer. Just leave the 8b’s connecting strap off the woofers binding post.
While Danny’s x/o keeps the single-amp design of the 3.7i intact, Magnepan’s design requires three separate power amps, one for each driver.
I think Magnepan got the idea from Rich Hollis. He showed an older pair of Magnepans with the Danville pricessor, Orchard amps and GR Reserach servo woofers at Capitol Audio fest.....and I think Magnepan heard them......and they were impressed.
What I am about to do this week is way more simple and way less expensive....and should be way cool. Same two 12 inch woofs that are used in the Caladan (burned in using 15 hz signal for over 125 hours) and then use just a coil on them and then a $50 mid/tweet planar from parts express filling in above 400hz. I am going to see if I can get away with no xover parts on the planar.....We are talking 93db open baffle system that would cost around $1500 to build. Will have more info shortly.
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.
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.
It is never just one thing that is important....Everything makes a difference. For instance, you can see on the Audiocircle site the latest thang from Hollis labs....He has a 1.7 maggy that he is tri-amping. However he put junk binding posts on the speaker and still has the fuses in line. These things wreck the sound. WBT Nextgen posts and no fuses would sound way better. Will Magnapan do the same with weekend on their tri-amped speakers at Axpona? And whose class D amps are they using (stock Hypex?). When LInkwitz showed his speaker in LA a few years ago they did an AB of the stock Hypex Ncore amps he normally sells and some Pass amps......most everyone preferred the Pass amps. Bruce at Eminent showed a prototype super triamped speaker at the Florida show a year ago and evreyone thought is was way cool. I bet he was just using stock Hypex amps in that thing. Your system is only as good as the weakest link.
I suggested to Bruce at Eminent Tech that he sell his new more effecient mid and highs planars on the baffle he showed at that show seperately (no woofers). Just wires hanging down. He would sell a ton at $3k. This way you can get his latest 90 db drivers on a baffle and make your own woofs and actively or passively crossover yourself.....for the best sound possible. Basically this is what Magnepan is going to do.....sell you the speaker with no xover parts and just binding posts on the back.
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. 😊
Ditto about improving Magnepan crossovers. M also makes bass panels, the DWM, which are a magnetic push-pull design just like their other bass panels.
I'm using two to complement my four Quad ESL's, and they sound pretty good - so I'm building a Bessel filter to eliminate that Butterworth phase shifter in the stock crossover. We'll see.
Why would anyone want to buy expensive magnepans to do this multi-amp thang? You can buy the GRS Planars from Parts Expres or the Radian ones and mount them on a baffle and have super sound for super little. A two way can be done with either of those drivers. Rich Hollis is going to design a line source using a bunch of the 10 inch Radians and use Servo woofs with them. However, any one can do this.....super simple. You no longer need to know how to design a xover or make a cabinet. You just have super dead and damped baffles with drivers you can buy.....and then get the Danville or Minidsp or other crossover and some amps and have fun. Check out what this guy did with an array of the $50 GRS planars.....he has 6 12 inch woofers on each side......all tri-amped with Ncore plate amps and digital xover.
What I am doing is a mini passive planar mid/tweet with woofs on the bottom. 2 12s and one single driver that he is using above. Each planar is 93db sensitive.
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.
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.
danny also reviewed a pair of magnepan mini WITHOUT THE BASS DRIVER. went about the review as tho he werent missing the bass driver. went ahead to talk about how theres no bass. wtf.
The 3.7I is built to a price successfully making it one of the great values in HiFi. I would biamp them using digital filters and add two sealed subwoofers using digital bass management.
Open baffle subwoofers are a silly concept. I have to believe they are popular with the DIY crowd because minimal skill and time are involved in making them. They are a sure recipe for terrible bass. This is not a IMHO situation. If you were able to compare a good sealed subwoofer system with an open baffle subwoofer system the problems with open baffle subwoofers would be immediately apparent. Yes, I have experimented with open baffle subs being a dipole user since 1978 and an avid DIYer. The argument that an open baffle dipole requires an open baffle subwoofer is another example of lay intuition.
@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.
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.
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.
However, they are supposed to be way more detailed and with more bass than the Maggies. It looks like they have announced some new models today. I think one of these could be my Magnepan LRS+ replacement.
My LRS+ has a new crossover mod. I was going to get that for $300 but I will checkout the smallest Diptyque first.
I like people with PhD they worked to get that education I. Think this is a good thing for magnepan and the audio world I like it when people get together and make improvements thx.enjoy the music
After seeing the video that OP posted and reading the PDF that I posted a link for, I was under the impression that the "X" upgrade kit would not be terribly expensive.
Therefore this description from Magnapan's site caught me by surprise.
$4000 for the "upgrade"?
The MG2.7i is a three-way speaker consisting of a foil bass and mid and a 40” True Ribbon Tweeter. The 2.7i can be thought of as an MG1.7i but with a True Ribbon Tweeter or an MG3.7i “lite.” In both performance and price it nestles perfectly between the 1.7i and 3.7i. Besides the Mini Maggies which are intended for desktop use, the MG2.7i is Magnepan’s smallest model with a True Ribbon Tweeter! As such it is perfect for use in smaller spaces or where the aspect ratio of our larger models isn’t quite desired.
MG2.7i’s can be purchased from a Magnepan Dealership for $5,995.00
The upgraded MG2.7x retails for $10,000.00
MG2.7i and 2.7x come standard with black or off-white T-feet; oval bases in black or off-white may be purchased for an additional $250.00
I saw a review a while ago on one of the smaller models, maybe the smallest model and they loved the sound, but the bass was lacking. (Imagine that) they can produce the sound, but without any umph and they suggested a small subwoofer or two to complement them.
@curiousjim in my small room I use the LRS+ with a CODA #16 amp and a KEF KC62 sub. Sounds seamless and strong on bass.
My only issue with the LR+ is the level of details I am hearing. This new crossover upgrade may solve my complaint. I am waiting on someone else to give me feedback on how those sounds.
I’d sure like to hear their top two models. I have always loved the sound of panels. I still have a pair of Acoustat Model X’s. I’ve tried probably a dozen times to make a subwoofer to go with them, buy never tried an open baffle design. I have a couple of 8” Dayton Audio woofers laying around and an old ARC crossover set ay 100hz. I guess it’s time to start reading up making open baffle subwoofers.
Good luck with the upgrade and please let me know your thoughts afterwards.
BTW, would you also tell me your thoughts on the KEF KC62? I’ve read/heard a bunch of reviews from “Professional” reviewers, but never from someone who doesn’t have something to gain from their reviews.
@curiousjim The KC62 is not a sub for explosions. It is supposed to be for music. I think it works great for that based on my usage with the KEF LS50 Meta speaker I had at one time and also the LRS+.
I was hard pressed to spend more money for the KEF Reference 1 when the LS50 Meta + KC62 sounded so close to the Reference 1. Maybe the KC62 had better bass.
My friend heard my office system the other day and he is a musician and recording engineer. He told me that he was surprised at how good the KC62 sounded with the LRS+. He said he could not tell that the bass came from a separate unit.
He is someone that knows what is in the "sausage" when it comes to music recordings. There are many times I ask him not to tell me the details of how something was recorded so as not to spoil the music for me in the future.
Main point is he knows how things should sound and he liked how the KC62 integrated with the LRS+.
BDP 24 - thank you for a wonderful thread about my fav speaker manufacturer - Magnapan. I guess I have taken my own journey to improve on my Maggie’s. I used Peter Gunn to upgrade my Maggie 1.6qrs three years ago. This was my retirement gift to myself those three years ago. My exposure to Duke on this site convinced me to buy his Swarm subs two years ago. The combination in my main listening room has surpassed my wildest expectations for sound. I demoted my Maggie 1.7is with the DMW base panel to my Mancave. I now just tweak positioning and minor room treatments to try and improve my sound.
Thanks again for helping educate a retired Chemist in his fav hobby!
Oh wow. There’s this system, "Music Transcendent", here in Audiogon. It that has all these mods, and more, done to a pair of 3.6s with subwoofer towers, and has been around for quite a few years. I wonder what it sounds like?
@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. 😉
I have been listening to Acoustat X speakers off and on for 40 years and have never really found a better sounding speaker. I recently heard a pair of $46,000.00 Wilson speakers and they did nothing better and the ported bass was no where near as fast and clean as my electrostatics. I still get that wow factor with the right recordings on my Acoustats. Bass is deeper and tighter than most subwoofers. I tried a Velodine ULD15 subwoofer and it added nothing and just blurred the bass I have. Acoustats are pretty much flat down to 29 HZ. I once compared the sound to a live symphony orchestra at Synod hall in Oakland, PA and to me the sound was the same.
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.
I use four subs to support my 20.1s. Two Kinergetics towers with five 10” Seas in individual enclosures powered by a Pass X-250. I also have two 16” sealed SVS SB-16 Ultras to fix the room modes. They integrate seamlessly and I vertically bi-amp my Maggies with a Danville crossover (what an upgrade from the MiniDSP) with all 8 channels containing 12 biquads each generated by REW and MSO. (I think it would be difficult to get the subs to integrate properly without these tools). A story to speak to the integration, we had company this last weekend who became one of three people brought to uncontrollable tears listening to their favorite piece of music because it transported them to the event. I am happy to say that no system I heard at AXPONA was better. The Danville room used a pair of Maggies as their demo for their crossover and the improvement it had very effectively. I did get a chance to listen to Dr. Edward Choueiri speak downstairs and listened his demo upstairs of BACCH 3D and it was astonishing how the walls disappeared. My wife, dad, and I were blown away. I built my system based on his principles I read about over 20 years ago. It was a real treat.
I agree that ditching the factory passive crossover was a huge improvement and I also bought Grant’s stands for my Maggie’s and the sound improved dramatically. I designed and had him build matching stands for my Kinergetics as well for both looks and stability. At AXPONA I was impressed with the Magico A5 speakers so much so I did research on the company that night and was very impressed that Alon Wolf, who I met at the show, stated in an interview that they support even their top speakers with multiple subwoofers to tame the room and the reviewer asked him if that was the easiest way to improve a stereo system and he said absolutely. I agree wholeheartedly.
Most of the Acoustat panel speakers can be modified to use the Acoustat servo amps. Roger Modjeski did some mods to my servo amps, but unfortunately he passed away before we could implement the tube input stage. I modded my Model 2s with help from Roger where we implemented his mod to increase treble dispersion to greatly widen the sweet spot. The challenge with the Model 2s is when you remove the interfaces to connect the servo amps the speaker is challenged to stay upright. Rob from Magna Risers made me custom feet similar to what he makes for Magnepan speakers and they work just great. I assume they work great on Maggies as well.
@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.
@bdp24I believe I do have the only Model 2s that are modded by Roger. My experience with Acoustat came from the fact that Roger had a pair of Xs. He used (actually butchered) the cabinet so that he could test his own ESL panel and power supply. I was using that pair of speakers in my system when until I spotted the Model 2s for sale locally. At which point Roger told me to grab them and we went to work on those. Sadly I will need to sell them and the servo amps, as well as two pairs of my 57s (including Rogers own pair that I had Sheldon Stokes restore). Other than running RAM Tubes I'm retired now and I just have too much stuff. I also do still have Roger's own ESLs with his direct drive amps which I will keep.
Crossing over ESLs at 80 to 100 Hz depending on the speaker makes a lot of sense. I wish more people would try it out. I think one of the more interesting developments in ESLs these days is David Janzen's reworking of the KLH 9 which his father originally designed. If I could only have a pair of those.
@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." 😉
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