Because I'd heard some nice things about the Ayre Acoustics V-3 as a partner for the MG-20, I asked for a loaner unit. This moderately priced stereo power amplifier ($3450) features a purist and innovative design with no global negative feedback, and displayed a giant-sized sweet spot through the upper mids. It managed to vitalize the MG-20's mid and upper registers with speed and transient finesse, while dishing out refined harmonic textures. Detail resolution and layering of the depth perspective were also strong suits. Despite its rating of 200Wpc into 4 ohms, the V-3 evinced dynamic compression when driving the MG-20 from loud to very loud—a task neither the Bryston nor the Classé had any trouble with.
The smoothest and sweetest solid-state drive I was able to find was the Pass Laboratories Aleph Null monoblocks. The Alephs run single-ended class-A up to about 40W, at which point operation shifts to class-A push-pull out to 75W into 8 ohms, and 150W into 4 ohms. While the Alephs don't exactly sound like SE triode amps, they do share the latter's disposition toward pure and liquid harmonic textures. Treble transients were so well-delineated, with perfect control and felicitous decay into the noise floor of the recording, that it suddenly hit me that the Aleph is a breakthrough product. It coaxed an amazing degree of low-level detail from the MG-20s without resorting to cheap tricks like etching or brightening textures so as to artificially enhance detail.
Preserving the crispness of live music without totally toasting harmonic textures is quite a feat. Reproduction of the corpus of a violin was particularly noteworthy. For example, Perlman and Zuckerman performing Bach's Double Concerto (EMI CDC 47856 2) never sounded more convincing. Soundstage transparency was such that I could clearly see its inner recesses. Instrumental outlines ebbed and flowed with lovely dynamic bloom. But, as with the Ayre Acoustics V-3, the Alephs also occasionally ran out of headroom when driving the MG-20s from loud to very loud.
All about tonal balance
The Magneplanar's strongest tonal suit was a full-bodied lower-midrange/upper-bass that fleshed out the power range of an orchestra—ie, up to about 500Hz—with justice for all. Reproduction of cello was especially impressive: gutsy, and rhythmically precise—no boxy resonances to smear pitch and intonation. I guarantee you this: anyone who's spent their audio career listening to boxes will no doubt marvel at the fact that such airy, detailed, and precise bass lines are possible in a speaker. However, there was no getting away from the fact that the lower midrange was emphasized in relation to the mids and treble. In my room, deep-bass extension was only flat to 40Hz. Presumably, it would have been possible to coax the bass response into the low 30s with speaker positions nearer the wall, but only at the expense of imaging precision. While the impression of bass punch was adequate, I became aware of moderate dynamic compression when the MG-20's woofer was confronted with a bass transient. In the realm of full-range planars, I'd judge the MG-20 a top performer in this department. However, when challenged by top-of-the-line cone woofers, the inevitable conclusion was that, as with other planars, bass dynamic range was restricted. The concussive clout of the best cone woofers (eg, the Genesis II.5) is not easily forgotten—that sort of impact and sheer intimidation were lacking with the MG-20. The MG-20's mid-treble (the 3kHz–10kHz range) sounded slightly recessed, on the order of 2dB down relative to the rest of the spectrum. The perspective was consistently that from Row R, the effect being a slight and natural dulling of the brilliance and presence regions that mimicked a back-of-the-hall tonal character.
Closely miked soprano voice, which should have sounded quite brilliant, was typically a bit less lively. In this respect, I preferred the Sound-Lab A-1's sunnier disposition. The A-1's harmonic sunshine and transient finesse painted the 3kHz–10kHz range with greater lucidity. The degree of verve and dramatic fire in the MG-20's sound were to some extent impacted by the associated gear. A brighter-sounding amp or front end, for example, subjectively worked better in this regard.
The joy of cooking
The similarities between gourmet cooking and bi-amping are unmistakable: The cook/audiophile is given a free hand to mix ingredients (amps and crossovers), concocting a final dish seasoned to his liking. The possibilities are enormous: the owner can experiment with crossovers, crossover frequencies, filter slopes, and power amplifiers. To constrain the enormity of the choice, I chose the Bryston 10B electronic crossover as the standard for this review. And while I tried a mixture of tube and solid-state amps (tubes for the top octaves, solid-state for the bottom), I did most of my listening with two pairs of Bryston 7Bs, because they worked so well with the Magneplanars driven full-range.
I settled on 18dB/octave high- and low-pass slopes at 200Hz as optimum—I didn't find the owner's manual's suggestion of 6dB and 300Hz to work as well for the high-pass signal to the midrange/tweeter. In the lower octaves, 18dB filter slopes tended toward the ideal because of their good selectivity and decent phase behavior.
The most obvious and immediate sonic benefit was a greater sense of ease through the midrange—as if the mids were able to breathe louder. When pushed hard, there appeared to be fewer distortion products than with the passive crossover network. There was a much lower perception of strain during loud passages. Clarity of harmonic textures also improved a notch, as the layering of complex passages was more readily resolvable.
I was also able to tweak the high-pass signal level 1–2dB, thus improving the perceived tonal balance through the upper-mids/presence regions. More boost than that, however, tended to over-brighten the treble.
Conclusion
Planar power! Fed by a high-calorie power amplifier, the Magneplanar MG-20 succeeded admirably in painting a cohesive, living soundstage populated by instrumental outlines of realistic proportion. Its other special gift lay in its natural portrayal of harmonic textures and dynamic bloom. The MG-20's robust tonal balance makes it a natural, of course, for accommodating a variety of music—from Bach to the Beatles. Although the passive network makes for a cost-effective alternative, the full glory of the MG-20 was only realized when the speaker was bi-amped with high-quality components. A subwoofer would extend the bass response to 20Hz, and increase the bass's overall dynamic range—in which case you might consider tri-amping. Even in its plain vanilla configuration with the passive network, the MG-20 was a world-class speaker, and one which has justly earned my respect. I could live happily with this speaker until the end of time.
The Magneplanar's strongest tonal suit was a full-bodied lower-midrange/upper-bass that fleshed out the power range of an orchestra—ie, up to about 500Hz—with justice for all. Reproduction of cello was especially impressive: gutsy, and rhythmically precise—no boxy resonances to smear pitch and intonation. I guarantee you this: anyone who's spent their audio career listening to boxes will no doubt marvel at the fact that such airy, detailed, and precise bass lines are possible in a speaker. However, there was no getting away from the fact that the lower midrange was emphasized in relation to the mids and treble. In my room, deep-bass extension was only flat to 40Hz. Presumably, it would have been possible to coax the bass response into the low 30s with speaker positions nearer the wall, but only at the expense of imaging precision. While the impression of bass punch was adequate, I became aware of moderate dynamic compression when the MG-20's woofer was confronted with a bass transient. In the realm of full-range planars, I'd judge the MG-20 a top performer in this department. However, when challenged by top-of-the-line cone woofers, the inevitable conclusion was that, as with other planars, bass dynamic range was restricted. The concussive clout of the best cone woofers (eg, the Genesis II.5) is not easily forgotten—that sort of impact and sheer intimidation were lacking with the MG-20. The MG-20's mid-treble (the 3kHz–10kHz range) sounded slightly recessed, on the order of 2dB down relative to the rest of the spectrum. The perspective was consistently that from Row R, the effect being a slight and natural dulling of the brilliance and presence regions that mimicked a back-of-the-hall tonal character.
The similarities between gourmet cooking and bi-amping are unmistakable: The cook/audiophile is given a free hand to mix ingredients (amps and crossovers), concocting a final dish seasoned to his liking. The possibilities are enormous: the owner can experiment with crossovers, crossover frequencies, filter slopes, and power amplifiers. To constrain the enormity of the choice, I chose the Bryston 10B electronic crossover as the standard for this review. And while I tried a mixture of tube and solid-state amps (tubes for the top octaves, solid-state for the bottom), I did most of my listening with two pairs of Bryston 7Bs, because they worked so well with the Magneplanars driven full-range.
Planar power! Fed by a high-calorie power amplifier, the Magneplanar MG-20 succeeded admirably in painting a cohesive, living soundstage populated by instrumental outlines of realistic proportion. Its other special gift lay in its natural portrayal of harmonic textures and dynamic bloom. The MG-20's robust tonal balance makes it a natural, of course, for accommodating a variety of music—from Bach to the Beatles. Although the passive network makes for a cost-effective alternative, the full glory of the MG-20 was only realized when the speaker was bi-amped with high-quality components. A subwoofer would extend the bass response to 20Hz, and increase the bass's overall dynamic range—in which case you might consider tri-amping. Even in its plain vanilla configuration with the passive network, the MG-20 was a world-class speaker, and one which has justly earned my respect. I could live happily with this speaker until the end of time.
