MartinLogan Neolith Electrostatic-Hybrid Loudspeaker

The Sword in the Stone

Equipment report
Martin Logan Neolith
MartinLogan Neolith Electrostatic-Hybrid Loudspeaker

The last MartinLogan speaker I had in my home was the Sequel back in the early 1990s. Despite some laudable attributes, its sound wasn’t compelling enough to convert me into an electrostatic devotee. True, the Sequel exhibited some of that magical transparency for which ’stats are famous, but the Sequel’s electrostatic panel didn’t blend all that well with its dynamic woofer. The cone simply couldn’t keep up with the ’stat in timbre and transient fidelity. Consequently, the bass sounded like an appendage being dragged around behind the rest of the music. The bottom-end’s character was so different that every time the bass drum went off I instinctively looked down toward the sound’s source. In addition, there was no getting around the lack of upper-bass/lower-midrange warmth and body, another consequence of an imperfect transition from panel to cone. Nonetheless, the Sequel and the Sequel II were great commercial successes.

But that was nearly 25 years ago, and to say that in the interim MartinLogan has been working on improving the electrostatic panel and its integration with dynamic woofers would be a colossal understatement. In fact, the company has pursued advancements in its core technologies with a single-minded zeal. In particular, Joe Vojtko, MartinLogan’s “Chief Audio Technologist,” has for the past 25 years led a team of engineers in pushing forward the state of the art in electrostatic design. Equally important, the team has worked on the seemingly intractable problem of mating an electrostatic panel to cone woofers to create a truly coherent, full-range loudspeaker system that speaks with one voice. Designing an electrostatic speaker is one challenge, but it’s an entirely different set of hurdles to create a hybrid electrostatic/dynamic speaker that has the weight, power, body, visceral impact, bass extension, and bottom-end dynamics of the best cone-based speakers. In fact, this challenge is audio’s equivalent of the Arthurian legend of the “sword-in-the-stone”—the seemingly impossible task of withdrawing the sword Excalibur from solid rock. But just as in legend, whoever accomplished this feat was ordained to discover the Holy Grail—in this case, the realization of a world-class loudspeaker that seamlessly mates the electrostatic’s famous transparency, resolution, and speed with truly full-range frequency response and dynamics.

MartinLogan’s Neolith considered here is the culmination of the company’s 33-year quest to perfect the electrostatic speaker. The Neolith’s name is a nod to its antecedent, the Monolith, the hybrid speaker that put MartinLogan on the map in 1983. Unlike many high-end companies that have been sold by their founders, MartinLogan has benefited from being acquired. The parent company has invested heavily in R&D as well as the specialized equipment and highly skilled labor needed to build large electrostatic transducers. As a result, MartinLogan has continually pushed its technology forward, most notably with its XStat electrostatic panel (see the accompanying interview with Joe Vojtko). This newer panel design represents a significant improvement over its predecessor, and has been employed with great success in the $25,495 CLX full-range ’stat, the $14,999 hybrid Summit X, and the $9995 hybrid Montis. All those speakers have received not just rave reviews in these pages, but have been repeatedly singled out by reviewers as rising above the competition. Jonathan Valin reviewed the CLX in Issue 190’s cover story, and was so enamored with them that he bought the review samples. Dick Olsher uses the Summit X as his reference.

The improvements to the electrostatic panel have been significant, but the work ML has done on blending the cone woofer with the electrostatic panel through careful crossover design (as well as the choice of woofer and how that woofer is loaded in the enclosure) has been just as important. Today’s Summit X and Montis deliver far better woofer integration than earlier generations of hybrids.

But it’s the massive and ambitious Neolith that takes all these technologies to their ultimate realization. This flagship speaker mounts a 48" x 22" CLS XStat panel atop an enclosure that houses a front-firing 12" woofer and a rear-firing 15" driver. Previous MartinLogan hybrids have used smaller panels and 8" or 10" woofers; the Neolith is clearly aiming much higher. The Neolith’s 12" woofer is mounted in a sealed enclosure and operates down to 60Hz; the rear-firing fifteen-incher is vented with two large ports, and handles frequencies below 60Hz. This is clearly a statement-level product designed to compete in the top echelon of today’s world-class loudspeakers. At first glance, and in theory, it may seem like a fool’s errand, or a recipe for disaster, to combine a 15" ported woofer with a nearly massless panel. But that was the design brief, and MartinLogan worked tirelessly to bring the Neolith to fruition.

Let’s look at some of the Neolith’s physical features and practical considerations before talking about how it sounds.

First, you should know that this is a big and imposing loudspeaker. Even though most of the Neolith is visually transparent, it nonetheless draws attention to itself by its sheer physical presence. The angular cabinet that houses the two woofers and supports the panel is substantial. MartinLogan offers the Neolith in seven colors, ranging from the same red found on Ferraris to a subtle silver. Two pairs of WBT binding posts are provided for bi-wiring or passive bi-amplification. Keep in mind that you’ll need to plug each Neolith into an AC wall outlet. The power draw is nominal—1W in standby and 15W in operation. The speaker automatically turns on when an audio signal is detected, and turns off when no signal is present for a specified time. The Neolith requires AC power to generate the polarizing voltages which create the electrostatic force that, when modulated by the audio signal, pulls and pushes the thin diaphragm back and forth. A recessed area in the woofer enclosure’s top panel provides a number of useful adjustments. By inserting jumper bars between pairs of holes, you can attenuate the bass by 4dB or 8dB (in addition to the flat setting) as well as adjust the crossover frequency between the panel and the 12" woofer, from 250Hz to 400Hz, in three steps that correspond to listening distances of 3m or less, 4m, or 5m or more. The greater the listening distance, the higher the crossover frequency should be. In my setup we opted for the lowest setting, 250Hz.

Sensitivity is fairly high at 90dB, but that figure is measured with a 2.83V input rather than the standard 1W, which, with a four-ohm (nominal) speaker such as the Neolith, increases the sensitivity rating (but not the actual sensitivity) by 3dB. That’s because 2.83V across 8 ohms dissipates 1W of power and 2.83V across 4 ohms dissipates 2W of power, thus making the speaker appear to be 3dB more sensitive than it actually is, since it takes twice the power to drive it to the same loudness level compared with a speaker measured with a drive signal specified as 1W. Although 90dB sensitivity is on the highish side, don’t think that the Neolith will be easy to drive. Its impedance drops with frequency, reaching a low of 0.46 ohms at 20kHz. Moreover, the load the Neolith presents to an amplifier is highly capacitive. The combination of the 0.43-ohm impedance and a capacitive phase angle will present quite a challenge to most power amplifiers. Don’t even think about driving the Neolith with anything but a stout amp that can deliver a lot of current into a low-impedance load. In fact, if you’re considering the Neolith you should audition it with the amplifier with which you intend to drive it.