MartinLogan EFX On-Wall Electrostatic Loudspeakers

The MartinLogan EFX is a slim, wall-mounted hybrid electrostatic loudspeaker designed for high-performance surround channels or space-conscious front-channel applications. A 28 × 8.6-inch XStat CLS electrostatic panel with 241 square inches of radiating area is paired with a 6.5-inch high-excursion fiber-cone woofer, delivering MartinLogan electrostatic performance from an enclosure only 6.5 inches deep. MartinLogan, Ltd.

For a MartinLogan home theater, the EFX provides an important advantage: surround channels can use the same fundamental XStat electrostatic technology as the front soundstage rather than transitioning to a conventional dynamic speaker.

28-Inch XStat CLS Electrostatic Panel

The EFX uses MartinLogan's XStat Curvilinear Line Source (CLS) electrostatic transducer, measuring 28 × 8.6 inches with 241 square inches of radiating area.

The low-mass electrostatic diaphragm handles frequencies above the 530 Hz crossover point, providing the speed, detail, and controlled radiation associated with MartinLogan ESL designs. CLS curvature produces 30° horizontal dispersion, while the 28-inch panel functions as a vertical line source. MartinLogan, Ltd.

MicroPerf XStat Technology

MartinLogan's MicroPerf stator technology increases the amount of exposed electrostatic diaphragm area without requiring a larger panel. The design maintains the rigidity required by the stators while allowing more of the diaphragm to contribute directly to acoustic output. MartinLogan, Ltd.

This allows the EFX to retain a narrow, visually lightweight profile while providing a substantial electrostatic radiating surface.

6.5-Inch High-Excursion Woofer

Low frequencies are reproduced by a 6.5-inch high-excursion fiber-cone woofer with an extended-throw motor assembly in a bass-reflex enclosure.

The woofer integrates with the XStat panel at 530 Hz, producing a complete specified frequency response of 68 Hz–22 kHz ±3 dB. MartinLogan, Ltd.

For theater systems requiring deeper bass, the EFX is naturally suited to operation with one or more properly integrated subwoofers.

Purpose-Built for On-Wall Installation

The EFX measures just 6.5 inches deep and includes a pivoting wall bracket, allowing the speaker to be aimed toward the listening area after installation. MartinLogan specifically designed the EFX for use as either an on-wall surround speaker or a slim front-channel solution alongside a television or projection system. MartinLogan, Ltd.

That makes the EFX particularly useful in premium home theaters where electrostatic surround performance is desired without placing floorstanding speakers around the room.

Audiophile-Grade Passive Crossover

The EFX uses an advanced passive crossover topology derived from MartinLogan's electrostatic loudspeaker development.

Its network incorporates a custom-wound E-I core transformer, air-core inductors, and metal-film capacitors, integrating the dynamic woofer with the electrostatic panel while preserving low-level information and dynamic capability. MartinLogan, Ltd.

Amplifier Matching

The MartinLogan EFX has 90 dB sensitivity, a nominal impedance of 6 ohms, and an impedance of 1.3 ohms at 20 kHz. MartinLogan specifies compatibility with amplifiers rated for 4-, 6-, or 8-ohm loudspeakers and recommends 20–300 watts per channel. MartinLogan, Ltd.

As with other electrostatic loudspeakers, amplifier stability into the EFX's low high-frequency impedance should be considered alongside rated wattage when selecting amplification.

Technical Details

MartinLogan EFX at The Grid HiFi

The Grid HiFi in Houston specializes in MartinLogan electrostatic loudspeakers and complete high-performance home theater systems.

The EFX is particularly compelling for building a MartinLogan electrostatic surround system without filling the room with floorstanding loudspeakers. The Grid can determine surround placement and aiming, match amplification, integrate subwoofers, and design the complete theater around the speakers, processor, acoustics, projection, seating, lighting, and control.

Building a MartinLogan electrostatic theater? Call The Grid HiFi at (713) 218-8120 for system design and a private consultation.