Magnepan 20.7 Loudspeaker

Unprecedented Full-Range Planar Sound

Equipment report
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Floorstanding
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Magnepan 20.7
Magnepan 20.7 Loudspeaker

As noted, another apparent improvement of the 20.7s over the 20.1s is in the linearity of phase response. With the 20.1s, on some material I would experience the sound wrapping somewhat around the sidewalls between myself and the speakers. But with the 20.7s, for the first time I hear sounds and possibly out-of-phase effects wrap not just around the entire wall, but also behind my head as well. I have heard this effect at some of my friends’ homes with very phase-accurate speakers, but I have not heard much of it before on the 20s. It substantially adds to the sense of air and space and helps the speakers disappear. For example, on the song “Climbatize” from the killer Prodigy LP Fat of the Land [XL], there is a whooshing sound at the beginning and interspersed throughout that, in the past, seemed to emanate from about the middle of the right sidewall. With the 20.7s, that sound now starts way behind me, seemingly from the middle of the rear wall. Now there are also holographic sound effects on the left side that I simply never heard before. At the end of the song there appears to be a shaker instrument of some type that previously seemed pretty holographic in the front half of my room. Now the sounds from the shaker tail off behind me, off the rear wall. I have had the same experience with a number of LPs and CDs—i.e., hearing holographic effects I did not know were there. Very cool stuff.

While the improvements discussed above are substantial and beneficial, where is this so-called “breakthrough” I have been trumpeting? It’s in the midbass and bass of the 20.7s. For many of you who have owned or listened extensively to full-range planars in the past, it may be safe to say that, while you admired the bass, you still were left wanting to some extent. You may have wanted more of the “slam” offered by good dynamic drivers. Or you may have wanted the woofer to plumb greater depths. Or you may have wanted both. I recall at New York audio shows in years past, even Magnepan demonstrated the 20s or 20.1s with cone subwoofers, not with great results. There was too much overlap between the Maggie bass and the subwoofers, leading to a muddy and ill-defined low end. Most owners of large planars that I have spoken with, whether those speakers be planar-magnetics or electrostatic, have wished for greater bass slam and extension while retaining all the high-definition “goodness” of their speakers. Many have tried and continue to use subwoofers, with varying amounts of success. Others refuse to use subwoofers out of concern for damaging the coherent and well-integrated bass already offered by their speaker.

But, with certain conditions being met, the midbass and bass of the 20.7s is so satisfying that I don’t think the thoughts “lack of slam” or “needs a subwoofer” will come to anyone, even on a subliminal level. This is the first large full-range planar I have heard that is fully convincing on orchestral bass, timpani, rock bass guitar and drum kits. On great orchestral material, you feel the full weight of the orchestra and are transported to enough of the recording space to lose sense of the dimensions of your room. On rock, electronic and dance music, you want to. . . . get up and dance (for me, if nobody is watching)! Isn’t this what the high end is supposed to be? In my view, if the bass isn’t right or close to right, the presentation is more polite and you lose many of these sensations.

But there’s always something, and the exemplary bass performance of which the 20.7s are capable does not come all that easily. I have written several versions of this section over the past few months and I have had to throw them all away. The ribbon tweeter and quasi-ribbon midrange sound really good “right out of the box” and only improve as time goes on. But the bass panel is a different story. When I first connected these speakers to the same equipment I have been using for quite a while on my 20.1s, I thought the bass was almost unlistenable. In fact, I could not understand why Magnepan released a speaker that sounded like this. The midbass was boomy, somewhat heavy and lacked control. There was low bass, but it too was boomy and various frequencies sounded distressingly like the same note.

But I learned that the key with this speaker is perseverance and patience, a lot of patience. Simply put, these speakers require substantial break-in and certain types of electronics seem to offer better results than others. No warning as to necessary break-in is offered by Magnepan in the somewhat sparse owner’s manual, but it should be. As I continued to play music, I could observe that the bass quality and quantity were changing, if not on a daily basis, then at least a weekly basis. Recordings that sounded unacceptable in the bass a week or two earlier, gradually started to sound tighter and more controlled, if not yet where I thought they should be. The speakers continued on their upward-sloping odyssey of improvement in this regard. I was not sure what awaited at the top of the slope, if indeed I could be certain I was at the top.

My reference amplifiers, VTL 750s, have always been a good match for the large Maggies. More than enough clean power, great sense of space and ease in presentation. Even though I continued to hear the bass response of the speakers improve over the course of the first 80–100 hours of listening (and I also played the speakers when I was out of the house), I started to wonder if an all-tube amp was the best choice for this bass panel. The midrange and highs were wonderful, but the bass was not yet in their league. Maggies have always sounded great on tube gear, indeed it is one of their strengths, but I thought experimentation might be in order for the 20.7s. I also thought it very possible, if not likely, that these speakers were developed using solid-state amps. But I am a tube aficionado and did not want to completely abandon the sound of tubes. What to do? I called Jim White of Aesthetix Audio, who was kind enough to loan me a pair of his Atlas Signature monoblock amplifiers. These hybrid amps feature a solid-state output with a tube input. They seem to offer damping and control similar to a purely solid-state amp and a lot of power—rated 300 watts into eight ohms and 600 watts into the four ohm load presented by the Maggies.

With the Atlas Signatures in the system, the midbass and bass immediately sounded more controlled and coherent. These amps seem to offer a better grip on the bass panels than the VTLs, although other all-tube amps may offer different results with these speakers. I did put the VTLs back in the system a few times as the speakers continued to break in—the bass continued to substantially improve and ultimately became quite acceptable, but never quite to the point of the Atlas. Sure, the presentation of the Atlas in the midrange and highs was not quite as “tube-like” as the VTLs, for better and worse, but the Atlas sounds more tube-like than not and seems to offer most of the benefit of tubes with the control and slam of good solid-state. Not a bad trade-off and, in my system, it sounds stellar. Moreover, the Atlas Signature monos are in a price range ($16,000 per pair) consonant with the purchase of the 20.7s, and the 750s are no longer being made. Most of the newer, high-powered all-tube amps are more expensive than the Atlas. Less powerful all-tube amps, especially newer designs with improved components, may be very satisfactory with the 20.7s as well. Experimentation is the key.

Almost all reviews of larger Magneplanars mention that the speakers need power. You will not read differently here. On the 20 Series I have had good luck in the past with tube and solid-state amplifiers in the 300-watt range, or larger. The speakers are relatively low in sensitivity although they do not appear to provide a difficult load for the amplifiers, at least for the amplifiers I have had available. Smaller amplifiers will certainly drive the speaker, but will probably not be adequate if you like to listen to large-scale music at levels approaching realism. Because these speakers are truly full-range and will reveal even subtle changes in the equipment chain, I believe it is safe to say that no amplifier is “too good” for the 20.7s. It should be noted, as Jonathan Valin pointed out in his blog, the Maggies still seem to need a little kick in volume before they really come alive and exhibit their best dynamics. And yes, the dynamic range of the 20.7 at full tilt is awesome, unprecedented in my view for a planar, but still not quite as wide-ranging as the largest dynamic and horn systems.

With the newly found transparency, coherence, and bass slam of the 20.7s, I also find them to be much more enjoyable at lower listening levels than the 20.1s. Still, the dynamic contrasts at low listening levels do not seem quite as pronounced as with a good cone or horn system. At the other end of the spectrum, I agree in general with Jonathan Valin’s conclusion that at higher listening levels you may not get all of bass weight and slam offered by larger cone woofers. Nevertheless, in my slightly larger listening room I find the bass output and quality of the 20.7s to be revelatory for a planar and very competitive with most large dynamic systems.

I cannot explain why it takes so long for the bass panels on the 20.7s to break in. I can speculate that it may be a function of the new capacitors being used in the crossover, or the initial tightness of the bass panel itself, or a combination thereof. At the present, with well over 200 hours on the speakers, I believe they are fully broken in. The end result: highly defined midbass and bass with no sense of boxiness or boom. Cellos and doublebasses seem real, with an in-the-room reality that is stunning. Bass drums and timpanis rumble and roll throughout the room, as in an orchestral hall. There’s more. The midbass has a degree of slam simply not heard before on a full-planar design. The kickdrum has real kick. Honestly, in my room it sounds as if Magnepan has somehow stuffed one or two very high quality 15" bass drivers into the cabinet, only with better definition. This is not hyperbole. If you have the opportunity or make the opportunity to hear a fully broken-in set of 20.7s, you will see and hear for yourself.

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