Classic ESL 9 is your ticket to a life-changing experience with a masterpiece of audio performance. This completely passive design features a 9.2-inch (CLS™) XStat™ electrostatic transducer, dual 8-inch aluminum-Cone woofers, and custom 5-way bi-wire tool-less binding posts.
Classic ESL 9 XStat panels are joined to their speaker cabinets using MartinLogan’s redesigned AirFrame Blade construction, precision manufactured from an aerospace-grade extruded aluminum alloy. This material, and this exclusive manufacturing process, makes the panels extremely rigid.
The bold, forward-moving styling of this AirFrame Blade rail system, narrow and strong in front, broad and forceful from the side, is a modern design statement. It never obstructs playable surface area or interferes with the panel’s dipole sound radiation pattern. It also provides electrical and acoustical isolation, minimizing intermodulation distortion caused by vibration and resonance. The flowing lines emphasize the groundbreaking integration of the panel itself with the compact woofer and amplifier section. The breathtaking AirFrame Blade design enhances imaging, low-level sonic detail, accuracy, and speaker efficiency.
CLS technology is an essential ingredient of every electrostatic loudspeaker we produce. Through our proprietary manufacturing method, we have built-in the panel’s gentle horizontal curvature. This unique design enhances the high frequency detail produced by the large radiating surface, without compromising overall sound quality. Notice how the gentle modern curve and perforation pattern gives way to the flat grille of the woofer section.
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 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.
Electrostatic panels, which are true dipole speakers, produce a nearly-ideal controlled dispersion radiation pattern. They send very little sound to the sides, thereby minimizing side-wall reflections, whose short arrival times tend to interfere with the perception of the direct sound. Their strong rear radiation, however, produces a generous amount of natural, ambience-enriching later-arriving mid- and upper register information.
Rounding out the dynamic performance of this Masterpiece is a passive pair of high-excursion 8-inch laser-engineered aluminum cone woofers custom designed by MartinLogan’s in-house engineering team. This efficient, cast basket woofer design improves cone suspension and the magnetic flux field, maximizing response time, to produce truly profound bass output (down to 34Hz) with vanishingly low distortion.
The woofers are balanced in an opposing array, one forward- and one rear-firing. This design greatly reduces cabinet vibrations inherent in same-direction woofer positioning, specifically in the 34Hz to 100Hz range. Roll-off characteristics for this opposing woofer array are further optimized for a realistically coherent bass wave form. In addition, we’ve tuned the rear-firing woofer to minimize near-wall interactions, perfectly complementing the dipole nature of the electrostatic panel. Bass performance from this configuration is accurate, musical and utterly lifelike.
A flared, ultra-low turbulence rear-firing slotted bass port is integral to the design of the enclosure, providing an extra layer of rigid internal bracing and increasing deep bass output with no added port noise.
MartinLogan's proprietary tool-less binding posts simplify cable connection and management. Two sets are supplied—one connected to the electrostatic panel and the other feeding the woofer. Listeners can choose to vertically/horizontally bi-amp the Classic ESL 9, or use jumper clips between the binding post sets for a single wire-connection. Classic ESL 9 features bi-wirable binding posts and provide the ultimate level of flexibility for connection and setup. To further simplify setup and cable management, Classic ESL 9 features a low-voltage DC power supply eliminates the need for a traditional, heavy IEC power cord.
The depth of Masterpiece Series speaker cabinets was carefully chosen to maximize benefits of advanced bass technologies, providing a level of low-frequency precision that is truly unique.
With ForceForward bass technology, the farther apart the woofers are from each other the lower in frequency its beneficial effects extend. MartinLogan’s ForceForward technology has solved a problem (found in nearly all speakers) where low bass frequency soundwaves reflect off the wall behind the speakers and interact with the waves traveling towards the listener. These interactions create non-linearity in those frequencies as they arrive at your ears and bass information suffers from both cancelations and excessiveness that is not accurate to the original sound. By selectively adjusting phasing of output from their opposing woofers, powered Masterpiece Series speakers eliminate problematic bass energy from behind the speakers.
ForceForward also simplifies the task of speaker placement by removing bass energy from behind the speaker and creating a uniform bass launch. This allows Masterpiece Series speaker cabinets to go closer to the wall than previous generations of MartinLogan speakers. As a rule of thumb we recommend placing the rear of the speaker cabinet no closer to the wall than the diameter of its woofer (Renaissance ESL 15A: 12-inches, Expression ESL 13A: 10-inches, and Impression ESL 11A and Classic ESL 9: 8-inches).
Additionally, due to their dipole nature, electrostatic panels perform best when placed at least 2.5-feet or more from the wall—a distance that is ideal for the front of nearly any high-end speaker, regardless of driver technology. The depth of Masterpiece Series cabinets lends itself to providing electrostatic panels with adequate distance from the wall, guaranteeing a richly detailed, three-dimensional soundstage.
34–23,000 Hz ±3dB
44" (112cm) line source
High Frequency Transducer
XStat™ CLS™ electrostatic transducer
» Panel Dimensions
44" x 9.2" (112 x 23cm)
» Radiating Area
405 in² (2,576 cm² )
Low Frequency Transducer
Two 8” (20.3 cm) cast basket, high excursion, rigid aluminium cone woofers with extended throw drive assembly, non-resonance asymmetrical chamber format
90 dB/2.83 volts/meter
4 Ohms, 0.8 at 20kHz Compatible with 4, 6, or 8 Ohm rated amplifiers.
Recommended Amplifier Power
20—400 watts per channel
Custom-wound audio transformer, air core coils, low DCR steel laminate coils, polyester capacitors
Custom 5-way bi-wire tool-less binding posts
Max: 2W per channel Standby: <1W per channel
78 lbs. (35.4 kg)
59.8" x 10.4"