New Magnepan "Concept Speaker" introduced at Audio Connection

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

I don't think anyone was questioning the quality of a four-woofer array. The research demonstrating that is well known, and as I said, a speaker designer I know (who played a role in the development of the new Maggie) compared four sealed woofers with two planar woofers and found their quality comparable.

I'd point out, though, that the new woofer is *not* a DWM, or a planar woofer at all. It's a dynamic dipole woofer that has response similar to the response of the 30.7's bass panels. Which is to say it isn't a sub, but neither is it a DWM, which is designed to reinforce the midbass and has limited output. It's designed to be small and easy to hide, though the woofers can be stacked in a large room.

(I wonder what happens when you use four dipole woofers in an array? It could potentially be smoother than either four monopoles or two dipoles!)

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