February 2001

Wisdom Audio M-50 Loudspeakers

by Todd Warnke

Review Summary Sound "Fast, open, uncolored and transparent" throughout the mids and highs, and "fast, free of distortion and compression, but also rich in nuance" down low; "near-perfect driver integration" -- " with only the most minimal of tonal shifts…the M-50s sound of one piece." Features Planar midrange/tweeter coupled with a dynamic woofer; Active Brain -- "a complex, hand-built active crossover"; large size is offset by gorgeous finish. Use Require four channels of amplification; Active Brain gives the M-50's great flexibility -- "each turn and twiddle of a knob made an immediately discernible difference." Value A successful assault on Mt. McKinley instead of Everest -- and more than commensurate savings.

Mt. McKinley

Memorable speakers usually fall into two camps. The first is that of the overachiever -- something like the Vandersteen 2 series or the Magnepan 1.6, speakers that each time you hear them leave you shocked that such quality can be had for so little outlay. The second is the cost-no-object, statement speaker. The first time I heard the $85,000 Dynaudio Evidence or the $67,000 Kharma Exquisite Reference 1B, I had my expectations of the possible seriously and permanently altered. But there is a third, more elusive camp, namely those speakers that aspire to and nearly reach the state-of-the-art yet cost fractions of the likes of the Evidence. While harder to categorize, being neither a budget speaker with finesse nor a budget-be-damned assault on the highest peaks of the audio art, the rare speaker that does fit into this category is truly memorable. One that does, at least to these ears, is the Merlin VSM-M. At $7050 (with battery BAM), it offers performance from about 40 cycles on up that is truly state-of-the-art. Sure, that $7050 is a lot of real-world dollars, but in state-of-the-art audio dollars, that’s not even a generous per diem. And it’s the combination of these two traits, true first-rank skills for relatively modest cash, that place it in the elusive third camp.

Of course, if $7050 is per diem, then the $18,900 USD that the Wisdom M-50 costs is, at least, a nice weekend trip in the state-of-the-art sweepstakes. Since we’re looking at the M-50, a good question to ponder is what does a near $20k speaker have to do to be worth the money, and perhaps merit inclusion in the third camp of memorable speakers? Obviously, a lot. It needs to offer world-class sound from somewhere close to 20Hz on up. It needs to offer a transparent, detailed and lifelike window into the recording, but without losing emotional context. It needs to be dynamic, both on the micro and macro levels. It needs to reward system upgrades without punishing unfairly other system components that might lag behind them. It needs to offer full-scale harmonic color. It should stage with accuracy, but not to the extent of turning an audio event into a visual one. And it should also be flexible enough to stay with you should you move or change listening rooms. Oh yeah, one last thing. If you want the Significant Other to approve the purchase -- after all, sliding almost $20k on the credit card isn’t quite as simple as hiding the purchase of the next Miles Davis boxed set is -- it should look like high-quality furniture as well.

Looking back at that list, I’m glad Robin had the sense not to compile an equivalent one before she married me. While not quite of Everest proportions, it’s a list of at least McKinley proportions -- an awesome sight, for sure, but terrible as well. And it's far beyond the skill of the average climber, or speaker designer, to summit. Yet that’s exactly the peak that Tom Bohlender at Wisdom Audio has set out to conquer with the M-50

Planning the expedition

Wisdom Audio was born out of Bohlender-Graebener, a speaker and raw-driver company founded and co-owned by Tom Bohlender. The reputation of B-G rides on their planar midrange-tweeter, and it’s quite a reputation, being the OEM supplier to, among others, Genesis and their line of statement speakers. But, like many of those possessed by a keen and restless mind, Bohlender was only partially fulfilled by the Bohlender-Graebener experience.

So in 1997 he formed Wisdom Audio with the express purpose of creating the best speakers in the world. The current embodiment of that thought is the $85,000 Adrenaline Rush. Using a highly modified 75" B-G midrange-tweeter per side and a separate low-frequency cabinet housing four 12" woofers per side, these monsters are aptly named. Every time I’ve heard them my inner urge to bungee jump Royal Gorge for the hormone kick has been slaked. On the other hand, not every adrenaline junkie has the cost of a weekend cabin rattling round the cookie jar, so the Adrenaline Rush is joined by the modest luxury-car-priced M-75 (a Rush mid/high unit with a separate woofer cabinet with two instead of four drivers a side and priced at $38,000), and also the, by comparison, affordable M-50.

In contrast to the big Wisdoms, the M-50 uses a 50" midrange-tweeter in place of their 75" units. The main reason for this is to allow a single-cabinet-per-side design, as the woofer, a single 12" unit per channel, is mounted in its own enclosure below the midrange/tweeter. The two sections visually integrate quite nicely. The midrange/tweeter, although a natural dipole, is mounted in an infinite-baffle cabinet that slopes backward at about a 20-degree angle to absorb the rear wave. The elegant shape of this cabinet flows down to the square-but-deep woofer chamber so that it looks more like a sail on an America’s Cup yacht than a speaker.

In building the cabinets, Bohlender uses true artisans to assist in his assault on the mountain. His cabinet builder is David Kunkle of custom-guitar fame and is located several miles down the road from Wisdom. Cabinet building is a reiterative process between Wisdom and Kunkle, who contributes his vast experience in woodworking and music. After Kunkle is finished with the cabinet, it moves several blocks away to another specialist, Mike Martin, who paints and bakes the cabinets. From there they move back up the road to the shop of Yves Stillmant, a musician, recording engineer and former Steinway finisher, who completes the cabinets to a "better than Steinway" gloss. The result really is a work of passion, skill and art.

The planar drivers, while sourced from Bohlender-Graebener, are a unique design to Wisdom Audio only. Tom Bohlender completely customizes them, with the result being what Wisdom calls the SMART planar, a driver that has better high-frequency extension, the removal of a resonant mode, and is easier to drive. The bass drivers (low-frequency regenerator, or LFR in Wisdom parlance) are massive. Each weighs over 40 pounds, 32 of which are the weight of the magnet assembly. This underhung driver (a short voice coil in a long magnetic gap) allows for three inches of excursion, with full control over the complete range.

Controlling everything is the Active Brain. A complex, hand-built active crossover, it has something like 4000 possible internal settings. These are best set by Tom Bohlender himself, and indeed they are: first at the factory to dial the M-50 in to match the performance of the reference model exactly, and then again in your home. That’s right -- when you purchase any Wisdom Audio speaker, Tom Bohlender comes to your house and refines the various internal switches on the Active Brain and then teaches you how to best use the four external controls. Those external controls allow you to adjust the Q of the woofers, the volume control on the low-pass side of the 24dB-per-octave crossover, the damping factor into the crossover, and the volume on the high-pass side of the crossover. In all, these controls allow Wisdom to match virtually any combination of room, amplifiers, and musical taste.

Yes, I did say amplifiers. The M-50, like all Wisdom speakers, requires four channels of amplification, one for each bass channel and one for each planar panel. To make sure that there was no compromise there, Bohlender arranged for a pair of Jeff Rowland Design Group Model 112 amps. These were well suited to the Wisdom speakers, and Tom Bohlender has used them at shows in the past.

I also needed two separate sets of speaker wires (not internal biwire) as well as three sets of balanced interconnects. Fortunately, George Cardas has an accommodating soul and sent me a full set of Neutral Reference. Once again, Tom at Wisdom has used this setup at shows and so was quite comfortable with the Cardas wire, but more importantly, so am I. Cardas wire is always my first choice, and I know the Neutral Reference quite well, so there was no change to my reference system when using it.

After I had the necessary pieces, setup went smoothly. I first placed the speakers with the fronts of the woofer cabinets in almost the exact same place where my Merlin speakers were, about four and a half feet from the front wall and separated by nine feet. I sit about nine feet back from the speaker plane. Over time I found that sliding the speakers in a tad and toeing them in just a scoosh more than I do with the Merlins resulted in a wide, deep, and stable image. Even though nine feet is pretty close to speakers that are six feet tall, the relatively slim cabinet and high-gloss champagne finish gave them an elegance that remained upscale without becoming imposing.

Finally, with the size of the M-50s, setting them up in the office system to break in was not feasible. So, to break them in without breaking me in as well, I set them up on a Friday morning, hit repeat on the CD player and took Robin camping in the mountains until the following Tuesday evening. Since Tom had run the speakers in before they left the factory, the 100+ hours of break-in was primarily for the new amps and wire and did a thorough job as the sound of the system underwent only minor changes during the review period.

Assault on the summit

I’ve been listening in on the Wisdom line since their first showing at HI-FI '97, and so I had some idea of what to expect when Robin and I got back from our camping trip (by the way, I mean camping in the real sense: no RV; no pop-up tent trailer; no condo in the Rockies; nothing but a tent, a sleeping bag, a Coleman lantern and stove, a cooler of food and real fires at night to make s’mores). But expectations and reality often have a way of diverging, so I was quite surprised when the first sounds I heard were quite similar to what Wisdom gets at shows: full range, very detailed but with a full harmonic palette, dynamic, and exceedingly clear. The speakers sounded so good that I spent several weeks just listening before I began to play seriously with the room placement and the Active Brain settings. I’m glad I did. As enjoyable as the first listening sessions were, the M-50 is so sensitive to setup issues that my round of tweaking was the most important week I spent with the speakers. Each turn and twiddle of a knob made an immediately discernible difference. And the challenge of balancing the speaker with my room was an education in itself.

While that sounds like it work, it wasn’t. The Active Brain is actually quite simple to use. The first rule, according to Tom, is to avoid adding gain on either side of the crossover, but rather to cut gain to balance out the sound. With that rule in hand, and by making slight adjustments to the Q (which controls LF extension) and damping (controlling the crossover blend) I was able to get +/- 1 dB frequency response from 60 hertz on up, +/- 2dB from 40Hz, and was down 3dB at 20Hz. What I learned from this experience is that J. Gordon Holt may be right: flat in-room frequency response is not always the best or most realistic sound. I eventually shelved the top down about 1dB and found my personal sweet spot. The result was still the flattest response I’ve had in my room, even if not quite as flat as the speakers are capable of. The real lesson here is that the M-50 is adjustable both for flat response and to taste.

Let’s get to the details of that final sound. The first characteristic of the M-50 is its near-perfect driver integration. Anytime you put dissimilar drivers together, as Wisdom does with their dynamic woofer and planar midrange/tweeter, the transition is where the trickiest waters lie. Navigating them requires the usual care with crossover issues, but more importantly, it requires special consideration in selecting drivers that correctly complement each other. The Wisdom planar driver is fast, open, uncolored and transparent; thus the woofer needs to offer the same characteristics while adding deep bass and dynamic power, all without having an obviously different tonal character. Score one for the Wisdom assault on McKinley. With only the most minimal of tonal shifts -- the bass being just the slightest amount richer in tone than the planar driver -- the M-50s sound of one piece. To these ears it is the remarkably overbuilt woofer that deserves the credit for the match, as it is blindingly fast, free of distortion and compression, but also rich in nuance while extending all the way down with tremendous punch. The driver combination results in a harmonious flow of musical waters.

Second, the M-50s offer the feel of unlimited resolution. On recording after recording I heard more deeply and accurately into both the performance and the recording session. To take a simple example, on the title track of Joni Mitchell’s Court and Spark [DCC GZS 1025], Joni is obviously in a separate booth, while the rest of the band (and what a band: Tom Scott on reeds, Larry Carlton on guitar, Joe Sample on keys, Max Bennett on bass, and John Guerin on drums) is spot miked, but in a common space. This is easy enough to hear on even entry-level high-end speakers, but what the Wisdoms do is draw out the individuality of each player and not just place Joni in different air from the rest, but give a sense of the volume of that air, even though it is an acoustically dead recording booth.

Better still than the amount of resolution and detail is the way the M-50s handle this resolution. Unlike the school of hyped and etched detail, which takes musical and sonic detail and blows it up and out of proportion to the actual event, allowing things like fingering on a guitar to assume greater import than the sound of the guitar itself, the M-50s reveal the smallest detail, but in proportion to the actual event. Thus, in the above example, the recording details serve not to distract or to isolate events, but to make it easy to see the session taking place before you with musicians spread right to left and Joni just left of center in a booth, listening to the feed on headphones and singing along.

Third, along with that resolution, the M-50s present music with a full and accurate harmonic palette. I’ve mulled this over and think that this may be the main reason these speakers are able to maintain such a sure grip on perspective. When each instrument is drawn in full, with body, range and depth, details are easily seen but not at the loss of the whole. The facts of both the playing and the recording come through unimpeded, but the emotional context remains rock-steady. This is done so well that Keith Jarrett’s vocalizing, something that never bothers me the several times I’ve heard him live but is almost always a distraction on recordings, really sounds like a guy sitting at a piano and humming in ecstasy while playing, rather than the disconnected, annoying buzz that most high-end speakers make of it.

Fourth, the control of the Wisdoms is impeccable. From the very lowest octaves all the way out to dog, cat and bat range, the M-50s are steady and composed. Sure, when playing something like Matthew Sweet’s "Girlfriend" at high volumes (from the album of the same name [Zoo 72445-11015-2]), the music careens around the edges of control, as it should, but the speakers are never stressed or unbalanced. What comes through is the feel of a musical event, with everything from bass-drum whacks, to guitars and vocals, to cymbals splashes, the M-50s reach top to bottom with joyful abandon and don't augment the chaos in the recording.

Fifth, the dynamics of the M-50s are superb. Placed in a system with the First Sound Presence Deluxe Mk II preamp, dynamics from the speakers took on Mohammed Ali-esque tones, floating like a butterfly in the quiet and subtle passages, and stinging like an Ali hook on crescendos.

Sixth, these things stage with Denali permanence. Images are life-sized, lifelike, layered and anchored. I love Bernstein’s DG Mahler recordings and often scare the hell out of myself with the Sixth Symphony [Deutsche Grammophon 215076]. The first movement begins with a rush and then settles to a nervous twitch scattered amongst the strings. With the Wisdom speakers, each player is firmly placed -- right to left, front to back, and with a precision I hadn’t known was on the recording.

And lastly, besides sounding the part, the M50s look it as well. Any thing six feet tall will occupy a significant part of the visual space of the room it's in. And on looks alone, the M-50s can justify their price tag. Polished to the overused jewel-like cliché, they are, indeed, fine pieces of furniture that even Robin found satisfying.

And there is another point worth mentioning, especially to music lovers (and I hope that’s what we all are). The recordings I’ve cited above are not, on the whole, sonic blockbusters. Oh sure, the M-50s handle the Super Disc list recordings just fine, drawing out every nuance in the grooves or bitstream, but where they really shine is in making music, not just sounds. So all those great performances that are found on run-of-the-mill recordings -- remember Holt’s Law, the better the performance the lesser the recording quality -- are as listenable as the insipid but beautifully rendered audiogeek stuff. This is, indeed, a rare, valuable and often overlooked skill.

Perfect? Right. Of course, there are drawbacks, but many of them are ancillary to the speakers themselves. First, four channels of high-quality amplification raise the cost of the speakers beyond their list price, as few of us already have four channels of power. Second, besides the amps, you’ll probably need new speaker wire, as internal biwire cables don’t work. Third, while I’ve heard of the M-50 (and its larger sibling, the M-75), being used in a 14' x 12' room, to get the most out of your investment, you’ll need at least a medium-sized room. I’d say at least 15' x 20'. On the other hand, the woofers suck up the juice, so the M-50 is probably not right for a large room. As for the speakers themselves, I suppose that in absolute terms the two dissimilar drivers pose a small issue. On the other hand, Wisdom integrates these dissimilar drivers better than 99.96% of audio companies integrate similar drivers. I also heard my upstream components with clarity beyond what I’m used to. While not punishing per se, the Wisdoms will certainly let you know the true skill of the rest of your rig. Other than that, about the only other drawback is the aforementioned need for juice, so if you are a SEThead or use OTLs (please see the TAS review of the M-75 for details on the writer's experience with the Atma-Sphere MA-2 amps), you will definitely be changing amps, and probably to solid state. Finally, I guess that all your audiobuds clogging the listening room may be a drawback as well, unless they spring for the munchies.

Other climbers

The closest competitor I’ve had in for review to the M-50 is the $10k Kharma Ceramique 2.0. My system was considerably different when it was here, and it’s been a while as well. Still, it left an indelible impression of smooth response, extreme musicality and deep, articulate bass. Compared to the M-50, it was a slightly softer on dynamic peaks, didn’t reach as deep in the bass, and had a few more issues with driver integration. It also had a slight tendency to a dark presentation and was a tad less revealing. Of course, we are talking about subtle differences as both these speakers are very near the edge of the possible.

View from the top

But the real story is that the Wisdom is sui generis. The large bass driver, coupled to an extended and detailed planar midrange/tweeter, controlled by an infinitely adjustable active crossover that can be tweaked to fit both room and amp, add up to a unique product, as the M-50s truly stand apart from the crowd. While no casual purchase, even for those who’ve avoided investing in a dot bomb company, the M-50s also fall short of the small-condo category of speakers. But just like H. L. Mencken, who said he could write better than anyone who wrote faster, and faster than anyone who wrote better, the M-50 is better than anything that’s cheaper, and far cheaper than anything that’s better. In my world, that makes it a truly memorable speaker, one worthy of inclusion in the third camp of the "affordable" state-of-the-art product. Sure, $18,900 is a helleva lot of cash, and certainly beyond what we call inexpensive here at the Warnke Snowshoe and Music Lodge. But when you are making a play for the best possible sound, nothing is cheap, and in that chase, the M-50 can be considered affordable. Kudos to Tom Bohlender and his assault on McKinley. He made it with ease and in style.

...Todd Warnke
todd@soundstage.com

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