I attended Mr. Diller’s Magnepan 30.7 demo in Indy a few months ago and those speakers are excellent but are priced at about $30K. I asked Wendell if he ever thought about combining and offering a 4-sub distributed bass array system (DBA) with a high quality pair of Magnepan panels for the mids and treble for a more reasonable price.
Unfortunately based on his reaction, I don’t believe he has ever heard of the DBA concept and how effective it has been proven to work in virtually any room both scientifically and anecdotally.
I knew at the time that I didn’t need to wait for Wendell to become enlightened to the DBA concept with Magnepans because I’d already been using an Audio Kinesis Debra 4-sub complete DBA system kit with an older pair of Magnepan 2.7QR speakers for about 4 years with excellent results; providing bass that is powerful, dynamic, smooth, fast, seemingly effortless that seamlessly integrates with the main speakers.
The $3K Swarm or Debra kit consists of four relatively small 4 ohm subs (14"w x 12"d x 24"h and 44 lbs that each contain a 10" aluminum long-throw driver and four port plugs for the choice of either ported or sealed sub operation) and a 1K watt class AB amp/control unit for powering all four subs in mono and setting the volume, crossover frequency and phase of all four subs as a group.
Knowing a mini Magnepan 30.7 system was a very good concept and for anyone else who thinks they may want to approximate this type of overall sound quality in their home, I believe I’ve discovered a method to achieve this; I replaced my older pair of 2.7QR with a preowned pair of Magnepan 3.7i speakers and combined it with my AK 4-sub DBA system. I’m using a Synology 20 TB NAS feeding a Lumin D2 dac/streamer a combination of FLAC, WAV and DSD music files with the output sent via balanced cables to the balanced inputs on a Levinson 326S preamp and on to the balanced inputs of a pair of D-Sonic M3-600-M class D mono-blocks. The D-Sonic amps provide 1,200 watts to the 4 ohm 3.7is which drive them very well.
The 3.7i have more midrange and treble energy than my former 2.7QR, with a much newer and improved quasi-ribbon mid-range section and a true ribbon treble section that allows for a very smooth, detailed, neutral and natural midrange/treble presentation that’s never harsh or bright and has a very high quality sound. Combined with the near state of the art bass performance provided by the AK’s 4-sub DBA system that seamlessly integrates, the result is an overall high quality sound from top to bottom that I perceive as very similar to a mini version of the Magnepan 30.7’s traditional open, natural Magnepan sound but with significantly better bass quality and a more dynamic quality overall.
But hey, we all know how subjective this whole home audio hobby can be. My main point is that the combo of a pair of 3.7i with high quality mid/treble and imaging performance paired with a 4-sub DBA system with high quality bass performance, in my opinion, already represents a legitimate mini 30.7 system at a fraction of the price. I paid less than $7,500 for a preowned pair of 3.7is and a new AK 4-sub DBA system.
I can certainly confirm that my custom mini 30.7 system combo sounds spectacular and definitely exceeded my expectations.
Tim
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I agree that the 30.7 is a great sounding pair of speakers but I'm really not looking to impress anyone except myself and my wife with my audio/video system and they're friggin' $30K a pair. Did I mention that I'm a frugal guy?
I think a frugal music lover is a good description of myself. I really enjoyed the 30.7 but never seriously considered buying a pair. I'm frugal but willing to spend money on high quality audio equipment if I believe it's going to make my music sound better and I consider the equipment somewhat of a bargain. I think that's what attracted me to the idea of a mini 30.7 system, although I didn't think of my system as a mini anything until I read this thread.
I was just very interested in upgrading my almost 25 year old 2.7QRs to a pair of 3.7is and already was well acquainted with the high quality 4-sub DBA system that would be an ideal pairing with them. In fact, I'm so frugal I was originally considering pairing my 4-sub DBA system with a pair of LRS or 1.7i until I auditioned a pair of 3.7i. To satisfy my frugal and bargain hunting nature, I bought a pre-owned pair of 3.7i for about $2K less than a new pair.
But I really do believe that combining a pair of 3.7i with a 4-sub AK DBA is one of the rare true bargains in high-end audio after experiencing the extremely high sound quality obtained through this bargain combination for a total of exactly 5 days thus far. I live in a suburb just north of Indy if anyone lives in the vicinity and would care for an audition, just send me a pm.
Tim
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mr_m:"Does it have conventional cone woofers like a hybrid, or no???"
The 3.7i are dipole 3-way planar-magnetic panel speakers with a true ribbon treble section, a quasi-ribbon midrange section and a quasi-ribbon bass section. The true-ribbon is very delicate and light weight foil transducer which results in it being very fast, accurate and detailed. The quasi-ribbon transducers consist of a slightly heavier polymer material which are also quite fast, accurate and detailed but just not to the same extreme degree as the true-ribbon. Both ribbon types utilize precisely placed small magnets for controlling movement and sonic output.
I was a bit concerned that the 3.7i's true ribbon treble might sound overly bright or harsh in my room currently lacking acoustic room treatments (soon to be remedied via several GIK products), thinking I likely would install the provided resistor to attenuate its output. But I've been experiencing nothing but very high quality and detailed treble response thus far with no sense of brightness or harshness playing them unrestricted.
Tim
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It makes a lot of sense that the true-ribbon and quasi-ribbon dipole plana-magnetic transducers, for the midrange and treble output, are positioned next to each other in the same panel. This is because soundwaves in these frequency ranges have a very directional radiation pattern that need to be precisely positioned in relation to the listener's ear positions when seated at the designated listening position in the room for optimum midrange, treble and imaging results.
Conversely, it makes very little sense for bass transducers, in any form (dipole, open baffle or dynamic), to be positioned in the same panels with or even in close proximity to the panels containing the midrange and treble transducers. This is mainly due to the fact that bass frequency complete cycle soundwaves are physically much longer than midrange and treble frequency complete cycle soundwaves. The lower the frequency, the longer its complete cycle soundwave and the higher the frequency, the shorter its complete cycle soundwave.
This results in a continuum of all audible frequencies having complete cycle soundwave lengths that are directly proportional; from the deepest audible frequency of 20 Hz having a complete cycle soundwave length of about 56 feet to the highest audible frequency of 20,000 Hz having a complete cycle soundwave length of a fraction of an inch.
Greater understanding of how we all perceive sound is gained by the fact that we are unable to localize sounds (determine exactly where the sound is originating from) at frequencies of about 80 Hz or less but increasingly more adept at localizing sounds at frequencies of about 80 Hz and above.
Some deep bass soundwaves have actual lengths that exceed the physical room dimensions in many typical domestic listening rooms and humans require at least one complete full cycle bass soundwave to be present in the room before our ears can detect it, send the information to our brains and have the brain create the perception of the corresponding bass tone. The brain also requires the input of multiple complete full cycle bass soundwaves to create the perception of a change in bass pitch. By contrast, our brains have a relatively easy task of creating midrange and treble tone and pitch perceptions due to their much shorter soundwaves.
Given the above, my main concern is the bass response performance of the Magnepan "Concept Speaker". Would I consider its bass performance, utilizing DSP but only 2 bass cabinets of unknown design with 6.5" woofers and seemingly positioned haphazardly, as fast, smooth, powerful, dynamic, effortless and detailed as the Audio Kinesis Swarm/Debra distributed bass array system (DBA), utilizing no DSP but 4 bass cabinets of sealed or ported design with 10" woofers and each sub positioned strategically and sequentially?
I think it's only fair that I reserve judgement until I actually listen to it. I attended a Wendell led demo of the $30K 30.7 speakers at a local high-end shop here in Indy a few months ago and was highly impressed.
When I asked him whether he ever considered combining the 30.7 or 3.7i speakers with a AK or custom 4-sub DBA system at a significantly reduced price, however, he seemed to be completely unaware of the scientifically proven and very effective 4-sub DBA concept.
This was not very confidence instilling but I decided to buy a pre-owned pair of 3.7i anyway and create my own "concept speakers". I'm certain that this combination represents a smaller version of most of the 30.7's very impressive attributes at a significantly reduced price of less than $10K, even with both purchased brand new.
Tim
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Hello bdp24 and josh358,
Have you two gentlemen ever listened to a pair of the Magnepan DWM dipole woofer panels? I intentionally described them as woofer panels, as opposed to subwoofer panels, because they only have rated bass output extension down to 40 Hz. I’ve listened to all the latest Magnepan speakers, all 3 top models from the 3.7i on up to the 30.7, combined with a pair of DWM dipole woofer panels and the bass they contribute is very well integrated with all 3 pairs of main speakers but their bass contributions always sounded to me as no deeper or impactful than mid-bass
Heck, each of my Magnepan 3.7i speakers basically have a large built-in dipole woofer section that are rated to have bass output extension deeper than the DWMs, down to 35 Hz. I run the 3.7i pair full-range and utilize the 4-sub AK Debra DBA system, with all 4 subs powered by the included 1,200 watt class AB amp/control unit and the crossover control set at 40 Hz, to supplement the bass in my system from 20 to 40 Hz.
From first hand experience using the monopole 4-sub AK Debra system with large 6’x2’ 3-way Magnepan dipole planar-magnetic panel speakers (initially the 2.7QR and now with the 3.7i) for the past 4 years, I can state with certainty that the bass produced by the AK 4-sub DBA system is just as fast, smooth, effortless, natural, detailed and seamlessly integrated with my main panels as the dual DWM bass panels I’ve heard, but with significantly better bass impact, dynamics and extension. It’s the difference between hearing some additional mid-bass emphasis and hearing as well as feeling the bass as experienced when music is heard and felt played live in person.
I’ve always respected Duke’s knowledge and experience and am aware he has made very positive statements in the past about the general bass quality produced by open baffle, line source and dipole speakers and subs. If he ever made the statement bdp24 has claimed, however, I seriously doubt Duke was referring specifically to comparing the bass performance of a pair of Magnepan dipole DWM panels to the bass performance of his AK Swarm or Debra monopole 4-sub DBA system. The differences in their bass performance quality are just too obvious and stark.
Jdp24 made the following 2 related statements:
#1: "The monopole characteristics of sealed and ported subs is a major factor in making the seamless integration of planars and subs as unsuccessful as so many have found it to be. Magnepan chose to go with an OB/Dipole woofer system in the proposed new model for exactly that reason.?"
#2: "The distributed array bass system addresses the problem of bass/room interaction, but does nothing to address the issue of the difference between monopole and dipole propagation. OB/Dipole woofers eliminate that difference. "
Both of these statements are demonstrably false and just serve to acknowledge your obvious lack of knowledge of, and experience with, the 4-monopole sub DBA concept that’s been scientifically proven to be remarkably effective in virtually any room and with any pair of main speakers by 2 separate PHD acoustical scientists, Dr. Earl Geddes and Dr. Floyd Toole,
You and any thread readers interested in research on the acoustics of attaining exceptionally good in-room bass response in domestic sized rooms can google both of these names and find an abundance of factual information on how and why the 4-sub DBA concept was developed based on these men’s research, along with the related contributions of Duke Lejeune and Todd Welti.
Tim
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Hello bdp24,
I completely agree with you that most systems sound bass shy.
I believe almost all music sounds its best when there's a solid bass foundation down to at least 20 Hz. I don't expect or want high SPL bass like an arena rock concert. My bass goal has been more the bass impact and quality one experiences when listening live to rock or jazz music
at a smaller club venue. I enjoy the perception that the musicians are playing in my room or I've been transported to the recording venue.
I know from experience that good bass performance is much more difficult to get sounding right than the midrange, treble and imaging in most rooms. This is mainly due to the bass soundwaves being much longer and behaving very differently in typical rooms than the much shorter and directional midrange and treble soundwaves.
Because of this, I prefer to treat my system as 2 systems: a bass system and an everything else system. Once I get the bass sounding optimum, it's relatively easy positioning the main speakers optimally in relation to my head and ears at the designated listening seat for very good midrange and treble performance along with a wide, deep and 3 dimensional soundstage illusion with solid, stable and natural images.
I've been able to attain what I consider near state of the art bass performance in my room utilizing the AK 4-sub DBA system without any room treatments or room correction software and hardware. I've also been able to attain very good midrange, treble and imaging results in my room without any room treatments and room correction. However, I do realize that an accurate room acoustics analysis along with the appropriate selection and positioning of various room treatments would likely result in even further improvements in my system's performance.
As a result, I've had GIK give me a free room analysis and I'm about to order a few thousand dollars of room treatments, including stacked bass traps in all 4 room corners and a roughly 5/50 balance of absorption and diffusion treatments for selected room surfaces throughout my room. I almost declined the recommended bass room treatments, since I was concerned about degrading the already exceptionally good bass performance in my room, but have been assured that these bass treatments will only further increase bass performance quality. I've decided to trust their knowledge and experience.
On another subject, you state:"It was here on an Audiogon post that I read of Duke telling an interested party that he recommended a dipole sub for use with dipole loudspeakers over a distributed bass array. I wouldn’t know how to find it now, but perhaps someone remembers it."
I've been thinking about this and I do recall Duke stating on another thread that he thought that a 4-sub line source bass array system would probably outperform his 4-sub distributed bass array system. This member did have a pair of Eminent Technology dipole planar-magnetic speakers.
This member had an odd room, where there wasn't a typical rear wall that bass soundwaves would normally reflect off of causing bass issues. Instead of a wall existing behind his designated listening seat, there was another room with the far wall in that room being a large distance away.
This member had 4 large subs aligned along his front 16' wall in a line or row, with all the subs less than 4' apart. He and Duke seemed to agree that, because there was no traditional rear wall and the 4 subs were aligned in a row with all being less than 4' apart, this constituted what's called a 4-sub bass line array.
Basically in this 4-sub bass line array, all 4 subs act as one giant sub and big bass soundwaves that are as wide as the room are effectively created that travel directly to the listening seat. If there's no wall directly behind the listening seat to reflect off of , the bass is perceived as very powerful, accurate, detailed and dynamic.
So, I believe Duke was stating that a 4-sub bass line array can outperform his 4-sub DBA if your room effectively has no rear wall for bass soundwaves to reflect off of, which I think you agree is highly unlikely for most individuals' rooms.
Duke definitely knows that the bass produced by his AK Swarm/Debra 4-sub DBA systems is sufficiently fast, smooth, accurate and detailed to seamlessly integrate with any pair of main speakers, even very fast and detailed planar-magnetic and electrostatic panel speakers. I think you would immediately recognize this obvious quality if you auditioned a 4-sub DBA in person.
Thanks,
Tim
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For those thread readers interested in trying out the 4-sub DBA concept in their rooms, I think it's simplest just to buy a complete DBA kit like the Audio Kinesis Swarm or Debra systems for about $3K. These systems consist of 4 relatively small subs(the Debra subs are each 12"dx14.5"wx18"h, weigh 44 lbs, have a 10" aluminum long-throw 4 ohm driver), a set of 4 sub port plugs for either ported or sealed sub operation and a 1,000 watt @ 4 ohm class AB sub amp/control unit with a volume, crossover frequency and continuously variable phase controls. This amp/control unit also has a limited band equalizer, left/right and LFE unbalanced rca inputs as well as 2 sets of speaker terminal outputs.
The AK Swarm and Debra 4-sub DBAs are both high quality systems. However, it's also possible for individuals to build a high quality custom 4-sub DBA system either as a DIY project, with the sub amp and all sub component parts sourced from retailers like Parts Express, or purchasing 4 self-amplified subs of one's own choice of quality and expense.
Just like everything else in home audio/video, quality matters, obviously varies between specific products and is very important in determining performance results. Millercarbon took the DIY route option, buying the exact same Dayton SA-1000 sub amp/control unit that the Swarm/Debra DBA systems use for less than $400 from Parts Express, sourcing his own sub cabinets and drivers and building his own custom subs. He and Duke agreed the drivers he purchased and used were more expensive but also even higher quality drivers than those used in the Swarm/Debra subs.
A second custom 4-sub DBA option is to buy the sub amp and 4 passive (unamplified) subs of one's personal quality/expense choice and then follow the sub positioning and amp configuration instructions detailed on my prior thread post. It's important with this option to ensure the sub amp has the required volume, crossover frequency and continuously variable phase controls.
Finally, a third custom 4-sub DBA option is to just buy 4 traditional self-amplified subs of one's personal quality/expense choice and then follow the sub positioning and amp configuration instructions detailed on my prior thread post. It's important with this option to ensure all 4 of the self-amplified subs have the required volume, crossover frequency and continuously variable phase controls; as well as realize that this option requires the user to set these 3 controls individually for each of the 4 subs rather than once, for all 4 subs as a group, like on the prior options.
The good news, however, is that some newer self-amplified sub brands even have the very useful added feature of being able to be configured to work together in a group in what is unfortunately termed a Master-Slave relationship, which functionally means the control settings made on the Master unit are able to be mirrored on each Slave sub able to be attached to the Master in a daisy-chain method. This is a very useful feature if one's attempting to create a multi-sub DBA system.
Tim
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Sorry, I need to make a correction and add a comment from my last post:
The 4 AK Debra subs are actually each 12"Dx14.5"Wx28"H, not 18"H as I mistakenly stated.
I also should have added that, no matter which option chosen, the utilization of bass room treatments, room correction software/hardware and DSP will not have negative effects and it's possible they may even have positive effects.
Thanks,
Tim
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