Most of you are probably too young to remember the Spendor BC-1 loudspeaker, a British design that garnered rave reviews in the late 1970s for its musical naturalness and imaging prowess. On cursory examination it seemed to be an ordinary three-way design, but, more to the point, it could best be characterized as a two-way design augmented by a super-tweeter. My initial take on the BC-1 was that the super-tweeter was nothing more than a token driver, a “hood ornament” whose sole purpose was to fill in the extreme treble. Only years later did I come to realize its importance in enhancing midrange transparency. At least conceptually, the M1 from ENIGMAcoustics reminds me of the BC-1, being a compact two-way stand-mounted speaker that is specifically designed to partner ENIGMAcoustics’ Sopranino super-tweeter in the extreme treble. The Sopranino (see review, Issue 235) is a self-biased electret tweeter, which in this application, sits on top of the M1. A cable is provided to connect it to the M1’s speaker terminals. Of course, the M1 easily trumps the venerable BC-1 when it comes to driver technology.
Let’s start with the woofer, a 7-inch custom design that features a polypropylene cone, a 2-inch voice coil, a highly compliant rubber surround, and an exceptionally strong and precise magnetic motor system. Quality control is said to be tight, with each batch of woofers being within 1dB of a standard curve. However, the key to this speaker’s sonic excellence is the tweeter. It’s a 34mm silk dome that was painstakingly developed utilizing considerable modeling, simulations, and much trial-and-error to achieve high efficiency (95dB) and usable bandwidth from 1kHz to 20kHz. The crossover frequency is a remarkable 1.1kHz, whereas the typical crossover frequency for a 1-inch dome is around 3kHz. This is a big deal in that it allows the M1’s woofer and tweeter to integrate far more smoothly than the average two-way is capable of and significantly improves the power response in the upper midrange. Push a 7-inch woofer to 3kHz and it starts to beam like a flashlight, meaning that its off-axis output drops dramatically. Experience has shown that a uniform power response in the midrange correlates well with perceived tonal-balance accuracy at the listening seat. It should also be emphasized that having what is essentially a low-mass point source of sound reproduce the core of the midrange and treble range yields an inherently more cohesive and focused presentation than is possible with two dissimilar drivers overlapping at 3kHz. I’ll have much more to say about these performance aspects a bit later.
The tweeter is protected by a third-order, electrical high-pass network, which is said to have been the most time-consuming design task, since the tweeter’s free-air resonance frequency is at 750Hz, less than an octave removed from the crossover frequency. It incorporates a 10dB resistive attenuation network to match the woofer’s sensitivity. The horn-flared tweeter faceplate compensates for a slight frequency dip in the 2–3kHz range, alleviating the need for a complex correction network. The woofer’s low-pass network is second-order, making the overall crossover an asymmetric type in that it combines second- and third-order networks. The advantage of such a network is that it provides a measure of time delay that is useful for phasing the tweeter and woofer in the crossover region. It is clear that the M1 is “a labor of love,” and this is reflected in the high-quality passive components used throughout: Mundorf EVO and EVO oil capacitors, Solen MKP capacitors, Cardas internal wiring, and WBT binding posts.
While in theory it’s possible to squeeze decent sound out of cheap drivers, my long held view has been that truly great speakers are built on the shoulders of superb drivers. The M1 reaps the benefits of in-depth engineering in the service of an outstanding driver complement. One of the quantitative benefits of this convergence is an exceptionally uniform on- axis frequency response as measured on the tweeter axis. Not only was the measured response exceedingly flat nearfield, but it also continued to behave extremely well when I moved the microphone to the listening seat. That translated directly into exceptional tonal-color fidelity. In-room bass extension measured flat to 40Hz nearfield and reached the mid 30s at my listening seat—superb performance from what is after all a rather small bass-reflex design.
The user manual offers detailed and generally useful guidance on how to set up both the main speakers as well as the Sopranino. The recommendation to align the Sopranino toe-in angle with that of the main speaker makes perfect sense, as does the advice to experiment with depth of placement relative to the front edge of the M1. There is a series of grid lines marked on the top of the main speaker cabinet, spaced about one-quarter inch apart, to aid in front-to-back positioning. Expect the treble balance to shift somewhat as you move the super-tweeter even a single notch along the grid lines, due to acoustic interference in the upper treble range between the silk dome (which isn’t electrically rolled off) and the super-tweeter. The manual pictures the Sopranino at its default position, which appears to be with the front edge of the enclosure’s base even with the third grid line. After experimenting with the Sopranino positioned at the first, second, and third grid lines, I settled on the third grid line, which in conjunction with a level setting of -3dB and a crossover frequency of 12kHz, not only measured best but also yielded the most natural overall balance. My ears tell me that the suggested default settings for gain and crossover frequency of 0dB and 10kHz sound too bright. There is a clear and present danger in trying to make the super-tweeter do too much. At some point, the balance crosses the line between the real and surreal. For me a bright balance is a serious matter, almost on par with a rift in the space-time continuum. I’m basically guilty of disliking a rising treble response and gravitate toward a mid-hall presentation. If your priorities are aligned with capturing the balance of the real thing, don’t be seduced by the dark side of the Force, and do stick with my recommended gain and crossover-frequency settings. Once you’ve adopted these settings, it may be perfectly fine to move the Sopranino forward to the first grid line. Doing so produces a more prominent treble impression, which may well compensate for treble roll-off induced by power amps with significant internal source impedance (i.e., low damping factor).
Impedance measurements indicate a box tuning of 36Hz. As is usually the case, the impedance magnitude is far from uniform. Significant features are a peak of about 50 ohms at the 1.1kHz crossover frequency and impedance minima of 4 ohms in the midbass and 2 ohms circa 15kHz. The impedance dip in the upper treble proved problematic for tube amplifiers, especially those with a source impedance over 2 ohms. In fact, every tube amp I tried produced some measure of treble roll-off. The best coupling for the M1 turned out to be the Lamm Audio M1.2 Reference monoblocks. Based on my experience, I’m convinced that the M1 would be happiest when partnered by a high-quality solid-state amplifier.
My first listen to an early version of the M1 was during a Consumer Electronics Show a couple of years ago. I was in for a big sonic surprise. Here was a small stand-mounted speaker, which I fully expected to exhibit a lack of testicular fortitude, and yet against all odds, it managed to portray the music’s foundation with believable authority. Small speakers are not supposed to do that, and none that I’ve auditioned in the past have done it as well as the M1, which explains my past lack of enthusiasm for this “imaging without guts” speaker genre. For me, a primary ingredient in the enjoyment of music reproduction is a realistic tonal balance, and in particular, a lower midrange weight that does justice to the orchestra’s power range. In this, the M1 succeeded reasonably well, to the extent that I was able to embrace its version of symphonic music. Bass lines were tight and free from the sonic muddle that accompanies a resonant enclosure. The M1’s rigid enclosure stands in stark contrast to the thin-walled British monitor class, which adds false warmth to the upper bass and lower midrange in the hope that this coloration, or should I say artificial boom, will somehow be consonant with the music. The M1 is serious about bass accuracy.
The front baffle is solid aluminum and is mounted to the main enclosure through the use of six stainless-steel pillars screwed to interior reinforced braces. Laminated birch wood is used for the enclosure body. Additionally, the top and bottom are reinforced by 12mm-thick tempered-glass plates, which, in addition to vibration control, add a nice aesthetic touch. The matching stands are also well executed and rigidly couple the main cabinet to the ground plane.
The payoff was evident in the M1’s majestic reproduction of the doublebass and cello bass-range with excellent pitch definition and timing. The 7-inch woofer generated a fair amount of punch on loud tympani strikes, though don’t expect it to equal the slam factor of a much larger woofer.
There was also much to rave about at the other frequency extreme. The treble range was capable of being sweet, cogent, and detailed without a trace of harshness. Struck cymbals shimmered with plenty of air, and massed string sound was simply luscious. Soprano voice was accommodated with superb timbre fidelity. One of my test tracks, and a favorite tweeter test, consists of a poorly recorded violin with occasional overload on loud transients. Most tweeters choke on it and it isn’t a pleasant sensation. The M1 did well here, negotiating the overload distortion without introducing any lingering lower-treble sizzle.
The wide-range tweeter facilitated pinpoint imaging that could only be described as spectacular. Image outlines coalesced in space around well-defined spatial coordinates, yet would expand spatially in concert with the ebb and flow of the harmonic envelope. Sitting in the sweet spot, with the speaker axes intersecting just in front of the listening seat, yielded a linear soundstage of remarkable depth and breadth, which was also totally untethered from the speakers. The M1’s disappearing act was as good as I’ve heard. But wait, there’s more. Its midrange and treble purity and transient control contributed to a superb sense of transparency. A recording’s ambient information was readily discernible as was low-level detail often fuzzed over by lesser speakers. It was this combination of soundstage transparency and palpable imaging that was responsible for the urge to reach out and touch some- one. However, as a planar speaker aficionado, I should throw in a couple of caveats at this point. First, I still prefer the image scale, and in particular, the illusion of image height that a good planar is capable of. Second, I don’t find a monitor class speaker with its controlled directivity produces a particularly im- mersive listening experience. Dipole and omnidirectional radiators do a much better job of that. However, what the M1 did extremely well was to offer a clean and tonally realistic window onto the soundstage.
My initial instinct was to protect, that is to baby, the silk-dome tweeter. But I need not have worried. It could handle loud playback levels with aplomb, that is, with little change in the distortion spectrum. Thus, the M1 should do well even in moderately sized room. The M1’s feel for microdynamic nuances and ability to scale the macrodynamic range from soft to loud captured much of the music’s dramatic content.
I suspect that the M1 will in due course garner a heap of critical praise, and indeed I’m about to jump on the bandwagon. But before I do, let me verbalize one concern, that is, that a speaker as clean and as tonally accurate as the M1 may fail to appeal to those who are after spectacular sound per se. To a great extent, the M1 will reflect the sonic character of the front end and matching amplification. It is extremely revealing of the rest of the chain and will only perform its best with top-notch gear.
With that out of the way, let me emphasize that the M1 Mythology wields considerable emotional power, which combined with exceptional tonal balance and an almost magical sense of transparency make it an insanely attractive proposition at any price point. It is a sure bet for music lovers. And you should know that it has given me many hours of musical enjoyment. The M1 is one of the very few compact monitor speakers that I could happily live with for years to come.
SPECS & PRICING
Frequency range: 40Hz–40kHz (w/Sopranino)
Sensitivity: 85dB (2.83V/1m)
Recommended amplifier power: 50–200Wpc
Nominal impedance: 4 ohms
Dimensions: 9″ x 15″ x 14″
Weight: 19 kg (speaker); 20 kg (stand); 2.7 kg (super-tweeter)
Price: $14,690 w/stands; $13,690 w/o stands
Irvine, CA 92618
Lamm Audio M1.2 Reference and Carver Cherry 180 monoblock amplifiers, AYON Stealth DAC Pre and April Music Eximus DP1 DAC, Sony XA-5400 SACD player with ModWright Truth modification; Kuzma Reference turntable; Kuzma Stogi Reference 313 VTA tonearm; Clearaudio Da Vinci V2 MC phono cartridge; Pass Labs XP-25 phono stage; Pass Labs XP-30 line preamplifier; FMS Nexus-2, Wire World, and Kimber KCAG interconnects; Acoustic Zen Hologram speaker cable; Sound Application power line conditioners
By Dick Olsher
Although educated as a nuclear engineer at the University of Florida, I spent most of my career, 30 years to be exact, employed as a radiation physicist at the Los Alamos National Laboratory, from which I retired in 2008.More articles from this editor
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