Magnepan’s “Tri-Center” Concept: Does Stereo Sound Better with Three Channels?

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Magnepan’s “Tri-Center” Concept: Does Stereo Sound Better with Three Channels?

I recently had the opportunity to visit Magnepan’s White Bear Lake, MN headquarters and manufacturing facility, partly for a factory tour, partly to get an introduction to the firm’s new Mini Maggie speaker system, and partly to hear an unorthodox “stereo” system that Magnepan had set up in its "skunkworks"-like listening room. It’s that latter aspect of my visit that is the subject of this blog.

Background

About a year ago I reviewed an excellent surround-sound speaker system comprised of a set of Magnepan’s motorized, two-way MMC 2 quasi-ribbon-type, dipolar wall-mount speakers (used for the left/right and surround channels), a CC5 quasi-ribbon-type center-channel speaker, and a set of DWM planar magnetic woofers (these augmented, at the very lowest frequencies, by a superb JL Audio f112 subwoofer). Magnepan’s head of marketing Wendell Diller came out to Austin to help set up the system and we wound up listening late into the evening, working on getting speaker positioning, channel level trims, and other system adjustments just so—all with the goal achieving spectacularly coherent surround sound (both for multichannel music and for movies).

As we worked on the system, it struck me that with Magnepan speakers it is relatively easy to get a system adjusted to the point where sound quality is very good; the hard part is pressing on through toward an even higher level of sonic quality, where imaging and soundstaging gel in a truly great way. The problem is that it’s so easy to get “very good” results that you’re tempted to settle for them, rather than doing the hard work of careful trial and error experimentation (and listening, listening, and more listening) until you get something more. But if you do that work, the fact is that the sonic rewards you’ll enjoy can be extremely satisfying.

In the course of our setup and tuning work—which eventually yielded fantastic results—Diller and I talked at length about exactly what role center-channel speakers can or should play, and discussed ways in which center channel arrays could, in principle, prove useful in high-end music systems (and not just for home theater applications). About then, almost as if by intervention of divine providence, we stumbled upon a few small but significant final tweaks that brought the review system to breakthrough levels of performance. And as a result, I had my answer to the “but will it work for high-end music listening?” question.

The answer is yes, a properly set up surround system can sound fantastic for music listening, maybe even better than a conventional stereo system can—even when listening to stereo source material (and I must admit I didn’t entirely see this one coming) through surround processing algorithms such as Dolby Pro Logic II. Diller just smiled at my reactions and mentioned that he and the Magnepan team had been experimenting with stereo systems that use a center-channel array, which he termed the “Tri-Center” concept.

“If you like what you’re hearing here in this review system, which I think is already quite good, then you really should come up to White Bear Lake to hear a demo of the Tri-Center in action.” What self-respecting audiophile/home theater enthusiast could resist an offer like that?

Into the Magnepan Listening Room—In the Dark

The Magnepan listening room is more a rough-and-tumble working lab than a posh listening salon, and for that reason I did not photograph the room. But if you ever have the chance to visit, here’s what you’ll find. The room is set up around perfectly positioned stereo pair of Magnepan 3.7’s planar/ribbon dipole speakers (or, I suppose, any other new speakers Magnepan might have under development). But here’s what’s unusual. The stereo system can be played in the normal way, using just the beautifully dialed-in left and right speakers, or it can be set up so that—in addition to the left/right pair of 3.7’s—a three-piece center-channel array (the Tri-Center array) can also be brought into play.

None of the above, however, is obvious when you first enter the listening room, since Diller is a big believer in conducting blind (as in “listen in pitch darkness”) listening tests, where you can’t see what is playing, nor do you know—in A/B comparisons—which system is which. Diller ushered me into the darkened room, then, somewhat humorously using a headband-mounted flashlight to guide my steps (this “lamp unto my feet” approach was calculated to make sure I would not trip over cables or lab gear). Once situated in the designated listening chair, we began to play music and make comparisons, using both a collection of demo tracks that Diller had assembled, plus a wide range of reference material (pop, jazz, classical, etc.) that I had brought along.

About Magnepan’s Tri-Center Array

That three-piece “Tri-Center” array consists of a pair of Magnepan’s MMC 2 quasi-ribbon-type wall-mounted panels supplemented by a Magneplanar CCR hybrid true ribbon/quasi-ribbon center-channel speaker. You can also use, and Diller did use, a set of Magnepan’s DWM woofer panels to help ensure absolutely phase-accurate bass as hear at the primary listening position for the left/right main speakers. To picture how the array looks, imaging a left/right pair of MMC2 panels, which are swing-out, wall-mount speakers, positioned vertically and several feet apart (with about the spacing you might use if the speakers were to flank a mid-size flat panel TV). The MMC 2’s are mounted fairly high up on the wall so that their top edges are roughly the same height at the top of the main 3.7 floorstanders. Then, below and directly between the MMC 2’s is the stand-mounted CCR. Together, these three speakers collectively serve as the “center channel.”

Great Stereo Is Its Own Reward

We started out with an acclimatization period where we listened to the conventional two-channel Maggie system. In stereo, the 3.7’s sounded terrific, and I must say that—on some pipe organ music I had brought along—they showed significantly deeper bass extension than I had expected on the basis of Jon Valin’s review of the speaker in The Absolute Sound (this didn’t entirely surprise me, since past experience with Magnepans suggests that their ultimate bass extension can be quite room dependent). Image size was beautifully scaled and exhibited the expected Magnepan ability to reveal image height. Resolution, timbral purity, and other sonic qualities were pretty much as described in Jon Valin and Harry Peason’s reviews, which is to say they were excellent. While some perhaps could or would pick minor nits, it was the sort of system that—on the whole—might leave even jaded listeners feeling impressed and well satisfied with the sonic results achieved.

But Wait, There’s More—Stereo Expanded

Just then, however, Diller engaged the Tri-Center array with results some listeners might have found downright shocking, and in a good way. Suddenly, images became more focused and palpable while depth cues in recordings were more fully delineated and explicit. At the same time, the overall three-dimensionality of the sound improved markedly. Timbres remained vibrant and pure, while certain low-level details became easier to discern, perhaps because their “anchor points” within the soundstage seemed more precisely defined with rock solid stability. In short, absolutely all of things we normally enjoy in great stereo systems actually got better with the Tri-Center array in play.

These observations were gleaned when I sat in the “sweet spot” listening chair, but at Diller’s suggestion I repeated my listening tests while deliberately sitting off-axis and found that from off-axis the impact of Tri-Center array became even more significant. When heard from off-axis, the normally fine imaging and soundstaging aspects of the stereo pair of 3.7’s can sound somewhat imprecise with center fill images that are noticeably less palpable and convincing than when heard from the “sweet spot.” But from off-axis, the sonic benefits of the Tri-Center array, which are pretty impressive even when listening from the “sweet spot”, are if anything even more apparent. Center fill images remain vivid and rock-solid when listening from either side of the central seat, and three-dimensional soundstaging cues likewise remain sharply focused. In short, the Tri-Center array effectively expands the useful listening area, so that it makes the vaunted Magnepan sound something that a whole couch full (or room full) of listeners could fully enjoy at the same time. This is a step forward, I think.

One point I can’t stress highly enough is that the stereo + tri-center presentation doesn’t sound at all strange, unnatural, “processed,” or garishly different from traditional stereo. Rather, it sounds much like stereo—replete with timbral purity, inner detail, expansive dynamics, killer imaging, realistic soundstaging, and so forth—only better, as if a subtle, underlying layer of sonic vagueness or imprecision has suddenly been banished.

The only caveat I would mention is that there was, at least during my first Tri-Center listening session, some shift in overall system tonal balance when the Tri-Center array was brought into play. I discussed this with Diller, indicating that I felt the balance shift was somewhat clouding my impressions of the benefits of the Tri-Center array. Diller replied that he had some Tri-Center tuning and set up ideas that might solve the problem and asked if I could return to Magnepan for a second listening session a day or two later. Since my flight scheduling allowed this, I quickly agreed and found that, on the second visit, Diller had successfully dialed in the system to a point where balance shifts between the pure stereo Maggie system and the Tri-Center system were very small, thus making the benefits of the Tri-Center even easier to appreciate than they had been before

How Does the “Tri-Center” Work?

The Tri-Center system, as shown at White Bear Lake, was powered by a very high-quality multichannel preamp/surround processor and a bank of beefy power amplifiers, all sourced from Bryston. When the system is played in conventional stereo mode, the Bryston pre/pro passes unprocessed stereo signals to the power amps and music happens. When the Tri-Center array is engaged, however, the Bryston’s surround sound processing circuits are brought into play. Incoming stereo signals are digitized (if they are not already in digital format) and routed through the Bryston’s Dolby ProLogic II processor, which uses a very specific set of Tri-Center configuration settings. The processor also manages time delay and bass management settings as necessary for the Tri-Center array (technically speaking, the Tri-Center is a “small” speaker, so the processor re-directs bass from the center channels to the left/right main speakers). The Dolby ProLogic II decoder creates the left, center, and right channels signals fed to the amplifiers and on through to the left/right 3.7 speakers and to the Tri-Center array. No rear or surround channels are used at all.

Conventional Wisdom is Wrong

Among audiophile purists, conventional wisdom would hold that less is more, that simpler signal paths always sound better than complex ones, and that two good channels will beat three channels plus a (gasp, choke, gag!) surround-sound processor—especially one with a comparatively humble Dolby ProLogic II decoder engaged. Now ordinarily, I would side with the purists on this point, but the simple fact is that conventional wisdom is wrong in this case. The Magnepan stereo rig as augmented with the Tri-Center array produced a sound that is arguably superior to the results achieved by traditional Magnepan 2-channel system (an extremely good system, by the way)—and without sacrificing any of the sonic qualities purists care about most. In fact, if anything, the Tri-Center array actually enhances some of those qualities, though never in an exaggerated way that would undercut musical realism.

Diller concedes that the Tri-Center concept may be too unorthodox to find widespread acceptance and that it probably won’t help Magnepan sell more loudspeakers, but his position is “it’s an idea that simply sounds so good that we just can’t keep it under wraps.” I’ll second that assessment and offer this bit of encouragement: if Magnepan ever brings the Tri-Center array to a trade show near you, do make a point of going to hear the system. At the very least, it should make one heckuva great conversation starter.

As It Turns Out, Great Audio Minds Sometimes Do Think Similarly

By the way, in case you are wondering, Magnepan is not the only company experimenting with something like the Tri-Center array. At the recent CEDIA 2011 show I had a chance to speak with none other than Richard Vandersteen about the idea of using three-channel systems to listen to stereo material. He explained that he, too, has done considerable research in this area, although his implementation of an appropriate audiophile-grade center-channel speaker is—as you might expect—quite different from Magnepan’s. Vandersteen told me that he often uses a three-channel configuration for his personal home music system, and that it can and does give impressive and musically satisfying results. Interesting, don't you think?

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