Controlled Dispersion PoweredForce At Work


Summit X Controlled Dispersion PoweredForce diagram. Summit X Controlled Dispersion PoweredForce diagram.

Controlled Dispersion PoweredForce eliminates side traveling waves as the woofer output approaches the 270Hz crossover frequency, matching the disperesion pattern of the electrostatic transducer

Summit X takes everything that was great about the original Summit and makes it better. Vojtko Voiced™ with a redesigned crossover and electronics, Summit X brings the magical electrostatic mid-range clarity of the CLX to a smaller package. Controlled Dispersion PoweredForce woofers tailor output to provide a low-frequency dispersion pattern at the crossover point mimicking that of our Controlled Dispersion XStat transducers. This breakthrough design provides dynamic, room filling bass at the lowest frequencies. By subtly shifting woofer phasing as it approaches the crossover frequency we minimize side-wall reflections and reduce problematic room interactions, while achieving seamless integration between the woofer and electrostatic transducer.

A flexible foot configuration allows listeners to easily adjust the controlled vertical dispersion of Summit X from -1° to 11°. The result? A superb sounding speaker that is easier than ever to integrate into every room!

Key to the Summit X's revolutionary performance is our advanced XStat™ electrostatic panel, which covers most of the audible range, from the midrange to beyond the limit of human hearing, with unprecedented accuracy. A perfectly integrated Controlled Dispersion PoweredForce™ woofer section—the most advanced woofer technology available in a full-range speaker—supplies an authoritative bass foundation from its twin 10-inch aluminum-cone drivers, effortlessly extending the Summit X's response to frequencies below where even most subwoofers reach. Yet the Summit X never, ever sounds heavy.

Nor does it look heavy. In fact, it almost seems to float in the air. We believe you'll agree that the Summit X looks nearly as good as it sounds—maybe because, like all designs, form follows function.

MartinLogan hybrid electrostats are a special breed of speaker, and the Summit X is the most special of them all. Hearing is believing.

Controlled Dispersion PoweredForce™ Bass

MartinLogan PoweredForce woofers feature advanced driver and amplification technologies that deliver astonishingly dynamic and articulate bass to as low as 24Hz from an enclosure only about the size of a case of wine. Controlled Dispersion PoweredForce woofers tailor output to provide a dispersion pattern at the crossover point mimicking that of our controlled dispersion electrostatic transducers. This breakthrough design provides dynamic, room filling bass at the lowest frequencies. However, by smoothly shifting woofer phasing as it approaches the crossover point we create a hybrid speaker that operates much more like a full range dipole (down to 160Hz) and brings with it all the requisite advantages of a controlled dispersion radiation pattern and uniform wave launch while still retaining the efficiency and dynamics that cone woofers provide at the lowest frequencies. By operating in dipole below the crossover point, the cones match the electrostatic panel when projecting sound into the room to provide controlled dispersion that minimizes side-wall reflections and reduces problematic room interactions in the midbass and midrange frequencies.

At the lowest bass frequencies (below 100Hz), the woofers remain in phase which is ideal for eliminating low frequency cancelation inherent to full range dipoles. This provides deep, dynamic low bass superior to that of most expensive high-end loudspeakers. Summit X is truly the finest hybrid speaker in the world, bringing all the benefits of both dynamic and electrostatic transducers into one seamless, easy to set up, and conveniently sized package. Additional 25 and 50Hz low-frequency equalization level controls further enhance performance by allowing precise tailoring to accommodate individual room acoustics.

The following graphs are idealized representations of the Summit X's bass response. Note on the graph titled 'Response: Behind Speaker', that the bass response at the lowest frequencies is in phase with the front response (indicated by the grey background). Between 100Hz and 160Hz woofer output shifts to become completely 180 degrees out of phase with the front response. In reality, this phase shifting is much more gradual than shown in the graph. It is simplified here to illustrate the concept. When the front and rear bass responses (sound waves) meet in the middle (at the sides of the speaker), the opposing phases cancel each other and cause the response to drop off as shown in the graph titled 'Response: Speaker Side'. Focusing wave launch above 160Hz to the front and back of the speaker effectively mimics the controlled dispersion pattern inherent to our electrostatic transducers. This allows the output of the dynamic woofer and electrostatic transducers to operate with a cohesive, aligned wave launch creating a seamless sonic presentation across the full range of sound while minimizing side wall reflections that muddle sonic detail and stereo imaging. To learn more about the advantages of controlled dispersion click here.



Summit X Controlled Dispersion PoweredForce graphs.

Grey background: In phase with front wave

Green: Woofer response behind speaker

Black: Woofer response in front of speaker

Orange: Woofer response to the side of the speaker



25- and 50-Hz Level Controls

Summit X's Controlled Dispersion PoweredForce active woofer system enables fine-tuning of the speaker's output in the frequency ranges most commonly and severely affected by room acoustics. The result is bass that is not just deep and powerful, but also smooth, clean, and detailed.

An aluminum cone woofer.

Laser Engineered Dual 10-Inch Low-Distortion Aluminum Cone Woofers

MartinLogan's engineering team utilized a sophisticated laser measurement system to map woofer performance during the development of Summit X. This precision tool allowed the engineers to understand, with extreme precision, the performance parameters of prototype woofers during the design process. The resulting data was used to refine the woofer and crossover design to obtain a powerful low-frequency performance that is rich in detail.

By eliminating cone flexure, aluminum diaphragms help our advanced-technology woofers achieve the very low distortion necessary for proper blending with MartinLogan electrostatic panels.

CLX Inspired, Precision-Built Advanced-Topology Vojtko™ Crossover

Vojtko Voiced with an advanced crossover and electronics, Summit X brings the magical electrostatic mid-range clarity of the CLX to a smaller package. Carefully hand-built using only the finest polypropylene capacitors and air-core coils, the crossover employs MartinLogan's proprietary Vojtko topology for vanishingly low distortion and seamless driver integration. This precision-tuned network preserves even the most microscopic sonic nuances while handling the full dynamics of any source.

A Curvilinear Line Source electrostatic transducer.

XStat™ Electrostatic Transducer

Advanced MicroPerf stator technology gives MartinLogan's latest-generation CLS electrostatic transducer almost twice as much exposed diaphragm surface as a traditional electrostatic panel of the same size. This dramatic increase in effective radiating area translates to higher efficiency and an even more effortless, unlimited dynamic presentation. The XStat pulls no punches!

But there's more to it than just putting more holes in the stators, which must maintain uniform spacing in front of and behind the diaphragm to exacting tolerances. They cannot flex. XStat's ultra-rigid aluminum AirFrame™ firmly anchors the transducer's working elements—stators and diaphragm—around their periphery, while ClearSpar™ spacers stiffen the assembly further across its width. ClearSpars enable precise, consistent tensioning of the Vacuum Bonded diaphragm without obstructing the floating, see-through look that is the visual hallmark of MartinLogan electrostats.

In the end, a speaker cannot outperform the signal feeding it. MartinLogan's state-of-the-art toroidal transformer and electrical interface engineering ensure an absolutely transparent link from amplifier to electrostatic panel. The result is sound of unparalleled purity, precision, clarity, and openness.

Parts of a MartinLogan AirFrame


MartinLogan AirFrame.

A) Top Strut
B) Compression Rod
C) Rod Isolator
D) ESL Transducer Isolator
E) Aluminum Side Pillar

Ultra-Rigid AirFrame™ Technology

XStat™ panels are secured to speaker cabinets using MartinLogan's AirFrame technology. AirFrames, manufactured from aerospace-grade billet and extruded aluminum alloy, make the panels extremely rigid without obstructing playable surface area or interfering with their dipole sound radiation. At the same time, they provide electrical and acoustical isolation, minimizing intermodulation distortion caused by vibration and resonance. Overall, AirFrames enhance imaging, low-level sonic detail, accuracy, and efficiency.

Vacuum Bonding

The components of each XStat panel—two insulated, high-purity carbon steel stators, plasma-deposited PET diaphragm, and ClearSpar™ spacers—are fused into a cylindrical-section geometry with an aerospace adhesive whose hold strength exceeds that of welding. Our proprietary Vacuum Bonding process ensures uniform diaphragm tensioning and facilitates the extremely tight tolerances necessary for construction of such a precision transducer.

Curvilinear Line Source Electrostatic Panel

One of MartinLogan's original breakthroughs, CLS technology has been an essential ingredient of every electrostatic loudspeaker we've produced. Proprietary manufacturing methods enable construction of electrostatic panels as cylindrical sections. Their gentle horizontal curvature solves the problem of obtaining good high-frequency controlled dispersion from a large radiating surface without compromising overall sound quality or reliability.

MicroPerf Stators

Although stators are the elements of an electrostatic driver that are supposed to stand still, they carry the audio signals that do the work of propelling the diaphragm back and forth to move air and produce sound. Because the stators sandwich the diaphragm between them, they must be perforated to allow sound to pass through. Yet they must also be rigid enough to remain absolutely stationary despite the strong electrostatic forces pushing and pulling at them during operation.

MartinLogan's MicroPerf design optimizes this tradeoff by reducing the size of the individual holes and using many more of them than in a traditional electrostatic panel. MicroPerf almost doubles effective diaphragm radiating area without compromising structural integrity. The resulting increase in output capability and efficiency allows a panel to be made much smaller without sacrificing performance—or to enjoy a substantial leap in bandwidth and dynamics without growing larger.

Portless Enclosure

Although ports are a convenient and cost-effective way of increasing low-frequency output, they rely on resonant energy in a way that impairs bass quality. A good sealed system will exhibit less transient-blurring group delay while maintaining smooth, consistent response regardless of output level or voice-coil temperature. Listen carefully to the sound of a bass drum, and you'll hear the difference.

Dipole sound radiation.

Controlled Dispersion Sound Radiation

The sound we hear from a loudspeaker is a combination of direct radiation from it to our ears and reflections off of room surfaces—walls, floor, and ceiling. How our brains integrate all this information is far from simple. Depending on the angle of incidence to the ears and the arrival-time difference between direct and reflected sound, reflections can either blur detail and stereo imaging or enhance the natural impression of depth and openness.

True dipole speakers, such as electrostatic panels, have long been noted for their near-ideal controlled dispersion radiation patterns. They send very little sound to the sides, thereby minimizing side-wall reflections with short arrival times that tend to interfere with perception of the direct sound. Their strong rear radiation, however, produces a generous amount of ambience-enriching later-arriving reflections off the wall behind them.

Summit X spike configurations.

Highly Adjustable Custom ETC™ (Energy Transfer Coupler) Spikes

The Summit X is supplied with sturdy, custom milled three-inch tall feet held in place by an ample 3/8-16 threaded insert. Optional ETC™ spikes are also supplied, which can be used in place of the standard feet to enhance stability on thick carpets or to create tighter coupling between speaker and floor.

A flexible foot design allows listeners to easily adjust the controlled vertical dispersion of the speaker from -1° to 11°, allowing an unprecedented level of fine tuning to achieve a superb sonic presentation in any listening environment.

Summit X ground effect lighting.

Control Panel and Ground Effects Lighting

The Summit X comes standard with an illuminated blue MartinLogan logo on the hood of the speaker. Additionally, a discreet light illuminates the back control panel to make easier the task of fine tuning the control settings. A unique ground effects light spills a subtle glow from beneath the speaker, creating an intriguing visual presentation in darkened listening rooms (just because it's cool)! All three lights are defeatable via a control on the back panel.

MartinLogan CLS (Curvilinear Line Source) electrostatic transducer.

Finish Options

Available in a variety of aluminum and hand-rubbed wood finishes, MartinLogan Summit X loudspeakers can be personalized to match any décor. Customers are invited to design their own Summit X in the MartinLogan Custom Shop.