mbl 101E Radialstrahler loudspeaker

Back in the late 1980s, when I was writing for The Abso!ute Sound and couldn't afford any of the audio gear I was reviewing, my system consisted of an Oracle turntable with Magnepan unipivot arm, a pair of Spica TC-50 loudspeakers, and a heavily modified Hafler DH-200 power amp and DH-101 preamp. It was a fun system that imaged like hell, but my fondest audio memories of that time were of visiting fellow TAS reviewer Dr. Michael Gindi, who lived on Manhattan's West End Avenue, and listening to his mbl speakers. (With his shrink's paycheck, he could afford them.)

Because Gindi also owned a Forsell turntable, the visit was always an adventure. To avoid compressor noise, air hoses of various thicknesses ran from the 'table, down the hall, and into the bathroom—which made the time water squirted from the arm's bearing all the more bizarre. The liquid had been literally squeezed from the air, as always happens when air containing water vapor is compressed, but that evening something had gone wrong with the compressor's moisture-removal system. Two images will remain with me for years to come: of water running from a hose in the bathroom and out the tonearm's air holes, and of Gindi, later that night or another, changing an LP as its static charge sucked an inch-long ash from his cigarette onto the record's surface.

But more than those visual images, it's the sonic ones that led me to want to review mbl's unusual but, ultimately, graceful-looking 101E Radialstrahler loudspeakers. When Gindi turned out the lights, the reach-out-and-touch-it reality produced by his mbls was unforgettable. The best part was that, no matter where I sat in the room—and Gindi used to invite a two-bench crowd—I heard everything in three dimensions, with my listening perspective shifted almost as it would be live. When the Doctor changed to an artificial studio recording, the stage would flatten appropriately, or lay bare multiple microphones in three dimensions with such clarity that I could hear groups of musicians clustered around each. The recording-specific differences in perspective left me confident that there was nothing artificial or pumped-up about the mbls' portrayal of space. The sense of hall expanse with good live recordings, such as those made in Carnegie Hall, was so compelling that it was easy to forgive the speakers' bottom-end shortcomings: the bass never seemed to be in the same time zone as the rest of the music, or of the same high quality.

mbl Radialstrahler inventor Wolfgang Meletzy and current chief designer Jürgen Reis have been working on that bass-integration problem in the years since, while refining the performance of their omnidirectional radiators, and of each mbl system as a whole. The result is the 101E ($44,900/pair). Like mbl's 111B, reviewed by John Atkinson in the August 2002 Stereophile, the 101E is a four-way speaker using what appears to be the same 24-segment carbon-fiber "bending-mode" tweeter and 12-segment upper-midrange driver. (The 101E's crossover points are 105Hz, 600Hz, and 3.5kHz.) Instead of the 111B's conventional lower-midrange drive-unit, however, the 101E has a large, visually unforgettable, 12-segment, football-shaped omnidirectional driver. When a signal is applied to the bottom-mounted voice-coils of these bending-mode drivers, they flex the segments, producing the omnidirectional wave launch. The three omnis perch atop a subwoofer enclosure with two front vents and a 12" cone designed and built by mbl.

Biwiring is a necessity: The 101E's woofer and mid/hi sections have their own sets of beefy binding posts, designed and built by mbl, on opposite sides of the cabinet's rear. The configuration also allows for biamping, which I didn't attempt. Also on the rear are three sets of jumpers: Smooth or Attack for the low/midrange; Natural or Rich for the mids; and Smooth, Natural, or Fast for the top. These jumpers don't change anything in the crossovers, but merely route the signal through different cables—or, as the instructions say, "only the molecular microstructure of its signal path is changed." Next time you're in front of a pair of these speakers with a "cable doubter," be sure to switch the jumpers around without telling him what's going on. He'll become a believer. (I ended up using the Smooth/Natural/Smooth connections.)

mbl's instructions, stiffly translated from German to English, are difficult to follow and need rewriting, especially given the unique and specific setup required for omnidirectional speakers. There is a very clear drawing of the triangle they want the two speakers and your listening position to form, and the optimum distances between the speaker and the front ("b") and side ("a") walls, but then it all falls apart.

I admit to being mathlexic, perhaps even mildly retarded mathematically and spatially, but I don't think even you would have an easy time with these instructions. It might help if distances were expressed as my tape measure and brain register them: in feet and inches instead of meters, especially since you're asked to use the ratio of 1.32m to 1.63m when calculating side-wall to rear-wall speaker distances, as in: "Distance 'b' between Radialstrahler and backwall = 1m, a/b = 1,32...1,63m)." Huh? If you're setting the speakers up on the short wall, as I did, the ratio is b/a instead of a/b. ?huH Once you've figured that out, be mindful that "If the triangle is kept, the sittingposition [sic] in front of the systems and behind the listener should not come up to the estimate of the measurement of the formula."

I'll say! Fortunately, mbl of America sent over Jeremy Bryan to do the initial setup, which I modified somewhat over time. (Coincidentally, Jeremy used to write for my old magazine, The Tracking Angle.)

With its omnidirectional radiation pattern, the 101E is not a speaker you want to use in an untreated or highly reverberant room, neither of which mine is. I'm not sure if I maintained the proper ratio or even came close; I used my ears. I also left the grille "pagodas" off, as recommended by Bryan. I like the space-age-bachelor-pad looks of the 101E in the raw.

Sound in the round?
Toward the end of the Home Entertainment 2004 East show last May, I visited the mbl room and played a CD-R compilation of tracks I'd recorded using the Rockport System III Sirius turntable or the Boulder 2008 phono preamplifier on the mbl 101Es. The sound of those tracks in that room's combination of high resolution, believable soundstaging, convincing tonal balance, and airy, soaring musical delicacy, transfixed me and the other visitors for almost an hour. I've played that disc a hundred times in a hundred places; that afternoon was among the best I'd heard it sound.

I looked forward to getting that sound at home, but the revealing nature of the 101Es meant that it would take just the right combination of placement and associated equipment to achieve it—and I'd never before had to deal with an omnidirectional speaker. When everything—or anything—was wrong, there was an odd chesty, compressed, almost grainy midbass coloration, and a sense that female singers centered between the speakers were performing in a closet in the next room. The offending sound was probably due to an unusual combination of placement and reflective interference.

But when that nastiness had been eliminated and everything had been optimized, including cables, AC treatment, and the jumper selections, look out! In my room, the mbls produced sonic sensations that lost a bit compared to the HE2004E presentation in terms of stage width, openness (my sidewalls were but a few feet from the speakers; at HE2004E, the walls weren't in the picture), and bass extension, but gained plenty in terms of clarity, image focus, midband resolve, and—especially—intimacy and immediacy.

US distributor: MBL North America, Inc.
263 West End Avenue, Suite 2F
New York, NY 10023
(212) 724-4870