MartinLogan Renaissance ESL 15A Electrostatic Loudspeakers

Complimentary White Glove Delivery • Travel Reimbursement*

The MartinLogan Renaissance ESL 15A is a full-range hybrid electrostatic loudspeaker built around a massive 46 × 15-inch XStat CLS electrostatic panel and an independently powered dual-woofer bass system. Its electrostatic transducer provides 690 square inches of radiating area for the midrange and high frequencies, while two 12-inch aluminum-cone woofers extend response to a specified 22 Hz.

Each woofer is driven by its own 500-watt Class D amplifier, giving every Renaissance ESL 15A 1,000 watts of dedicated internal bass amplification. A 24-bit Vojtko DSP engine manages the low-frequency system, while PoweredForce Forward technology controls the interaction between the opposing woofers and the wall behind the speaker. Anthem Room Correction adds another level of low-frequency optimization for the listening room.

The result is an electrostatic loudspeaker that preserves the speed, transparency and controlled radiation of a large CLS panel while solving one of the most difficult challenges in hybrid speaker design: integrating an electrostatic transducer with deep, high-output dynamic bass.

46 × 15-Inch XStat CLS Electrostatic Panel

The Renaissance ESL 15A uses a 46-inch-tall by 15-inch-wide XStat electrostatic transducer with 690 square inches of radiating surface.

Rather than dividing the midrange and treble between multiple conventional cone and dome drivers, the electrostatic panel reproduces the entire spectrum above the 300 Hz crossover point.

An extremely lightweight conductive diaphragm is suspended between perforated stators. The musical signal creates changing electrostatic forces across the diaphragm, causing its entire surface to move.

With dramatically less moving mass than a conventional cone and voice-coil assembly, the panel can respond to extremely small changes in the signal without requiring multiple mechanical driver systems throughout the critical midrange and treble.

Curvilinear Line Source Geometry

A large flat electrostatic panel naturally becomes increasingly directional as frequency rises.

MartinLogan's Curvilinear Line Source, or CLS, technology introduces a precisely controlled horizontal curvature into the electrostatic panel.

The Renaissance ESL 15A provides a specified 30-degree horizontal dispersion pattern, expanding the useful listening area while retaining the controlled radiation characteristics that make a large electrostatic panel fundamentally different from a conventional multidirectional loudspeaker.

Vertically, the 46-inch panel behaves as a controlled line source.

MicroPerf Stator Technology

The stators surrounding an electrostatic diaphragm must perform two conflicting jobs. They need to remain extremely rigid while allowing as much acoustic output from the diaphragm as possible to pass through them.

MartinLogan's MicroPerf stator technology uses an optimized perforation pattern that substantially increases the amount of exposed diaphragm surface compared with earlier electrostatic constructions of similar dimensions.

The greater open area allows more of the panel's active diaphragm to contribute directly to the acoustic output.

ClearSpar Panel Reinforcement

The transparent horizontal structures crossing the electrostatic panel are MartinLogan's ClearSpar spacers.

They reinforce the large electrostatic assembly and maintain precise spacing and diaphragm tension without substantially obstructing the panel's radiating surface.

Maintaining consistent geometry across a 46 × 15-inch electrostatic diaphragm is critical. Small variations in the relationship among diaphragm and stators can affect the behavior of the transducer.

ClearSpar provides the necessary structural support while preserving the Renaissance ESL 15A's characteristic transparent appearance.

AirFrame Blade Construction

The electrostatic panel is supported by MartinLogan's AirFrame Blade, manufactured from aerospace-grade extruded aluminum alloy.

The structure is narrow when viewed from the front but considerably deeper from the side, creating the rigidity required to support the large electrostatic panel without unnecessarily obstructing its radiating area.

The AirFrame Blade also mechanically separates the electrostatic panel from the woofer enclosure, reducing the transfer of vibration generated by the large dynamic bass drivers into the electrostatic structure.

Dual 12-Inch Aluminum Woofers

Low frequencies are generated by two 12-inch high-excursion woofers with rigid aluminum diaphragms and cast baskets.

Each woofer operates in its own independent sealed chamber.

Separating the two bass drivers allows MartinLogan to control their behavior individually through amplification, DSP and phase management rather than treating them as a conventional pair of woofers sharing the same enclosure.

The system reaches a specified 22 Hz at ±3 dB, giving the Renaissance ESL 15A genuine deep-bass capability without requiring an external subwoofer for full-range music reproduction.

1,000 Watts of Dedicated Bass Amplification Per Speaker

Each 12-inch woofer is powered by its own 500-watt Class D amplifier.

That provides 1,000 watts of dedicated internal bass amplification in each loudspeaker, with 2,000 watts of peak capability.

The user's external amplifier therefore does not directly provide the power required to drive the two large bass woofers.

Instead, the main amplifier drives the electrostatic section while the internal amplifier system supplies the substantial power required by the low-frequency drivers.

This architecture allows MartinLogan to optimize the amplifier, DSP and woofer system together while reducing the bass-current demands placed on the external amplifier.

24-Bit Vojtko DSP Engine

The powered bass system is controlled by a 24-bit Vojtko Digital Signal Processing engine developed by MartinLogan.

The DSP controls low-pass filtering, woofer equalization, phase relationships and limiting within the bass section.

Because MartinLogan controls the drivers, amplifiers and digital processing as one system, the low-frequency architecture can be optimized around the exact electrical and mechanical behavior of the Renaissance ESL 15A rather than relying exclusively on a passive crossover network.

The transition to the electrostatic panel occurs at 300 Hz.

PoweredForce Forward Bass Technology

One of the most important technologies in the Renaissance ESL 15A is PoweredForce Forward.

The two woofers are positioned on opposing sides of the enclosure. MartinLogan uses DSP-controlled phase relationships between them to reduce problematic bass energy radiating toward the wall behind the loudspeaker.

Low-frequency reflections from the front wall can return toward the listening position and interact with direct bass output, creating peaks and cancellations.

PoweredForce Forward is designed to reduce that interaction at the source.

The practical benefit is greater placement flexibility and more predictable bass performance before room correction is applied.

Anthem Room Correction

The Renaissance ESL 15A is Anthem Room Correction ready.

ARC measures the low-frequency response of the loudspeakers within the actual listening environment and compares those measurements with a target response. It then creates correction filters for the powered bass system to address room-induced peaks and other low-frequency anomalies.

Importantly, ARC operates on the powered woofer section, preserving the direct signal path to the electrostatic panel.

The required ARC or PBK measurement microphone kit is sold separately.

Independent Bass Adjustment

Room correction is not the only method available for tailoring the Renaissance ESL 15A to its environment.

The loudspeaker provides two physical low-frequency controls.

The bass control provides ±10 dB adjustment below 75 Hz, allowing substantial control over deep-bass output.

A separate mid-bass adjustment provides -2 dB, 0 dB or +2 dB settings.

These controls allow the bass system to be configured around placement and room behavior even without running ARC.

Dipole Electrostatic Radiation

The XStat panel operates as a dipole radiator, producing acoustic energy from both its front and rear surfaces.

At the sides of the panel, the opposing wavefronts largely cancel. This substantially reduces lateral radiation compared with a conventional box loudspeaker.

Less energy is therefore directed toward nearby side walls, reducing early reflections that can interfere with stereo localization.

The rear radiation remains an important part of the speaker's presentation and makes distance from the wall behind the electrostatic panel a critical element of setup.

Advanced Vojtko Crossover

Integration between the electrostatic panel and powered woofer system is handled through MartinLogan's Vojtko crossover architecture.

The passive portion uses components including custom-wound audio transformers, air-core inductors and polypropylene capacitors.

The bass system adds 24-bit DSP and dedicated amplification.

Combining passive electrostatic crossover engineering with active DSP bass management allows MartinLogan to treat the two fundamentally different transducer technologies according to their individual requirements.

WBT nextgen Binding Posts

The Renaissance ESL 15A uses WBT-0703Cu nextgen 5-way binding posts.

The signal conductors are manufactured from gold-plated, nickel-free, non-ferromagnetic pure copper. WBT minimizes conductive mass in the signal path and designs the terminals to avoid eddy-current effects associated with conventional high-mass metal binding posts.

The connections accept substantial high-end loudspeaker cabling while providing a secure mechanical interface.

Amplifier Matching

Although the bass system is internally powered, the electrostatic panel still places meaningful demands on the connected amplifier.

The Renaissance ESL 15A has a 4-ohm nominal impedance that falls to 0.5 ohm at 20 kHz.

MartinLogan currently specifies recommended amplifier power of 20 to 700 watts per channel and compatibility with amplifiers rated for 4-, 6- or 8-ohm loudspeakers.

Wattage alone, however, does not describe amplifier compatibility with an electrostatic load. Stability, output-stage design and the amplifier's behavior as impedance falls at high frequencies should all be considered when building the system.

92 dB Sensitivity

MartinLogan specifies sensitivity at 92 dB with 2.83 volts at one meter.

Combined with the internally amplified woofer system, this allows the external amplifier to concentrate primarily on driving the electrostatic panel rather than supplying the enormous current required for deep bass from two 12-inch dynamic woofers.

This opens a particularly interesting range of amplification choices, including high-quality solid-state and appropriate tube electronics.

Technical Details

Specification	MartinLogan Renaissance ESL 15A
Product Type	Powered Hybrid Electrostatic Floorstanding Loudspeaker
System Frequency Response	22 Hz to 21 kHz ±3 dB
High/Mid Frequency Transducer	XStat CLS Electrostatic
Electrostatic Panel Dimensions	46 × 15 in / 116.9 × 38.1 cm
Electrostatic Radiating Area	690 in² / approx. 4,450 cm²
Panel Technology	CLS / XStat / MicroPerf / ClearSpar
Panel Frame	AirFrame Blade
Horizontal Dispersion	30°
Vertical Dispersion	46 in / 116.9 cm line source
Low-Frequency Drivers	2 × 12 in / 30.5 cm
Woofer Construction	High-excursion rigid aluminum cone
Woofer Basket	Cast
Woofer Enclosures	Independent sealed chambers
Bass Technology	PoweredForce Forward
Internal Amplification	2 × 500 W Class D per speaker
Internal Peak Amplification	2 × 1,000 W
Bass Processing	24-bit Vojtko DSP
Crossover Frequency	300 Hz
Room Correction	Anthem Room Correction Ready
ARC Kit	Sold separately
Deep Bass Adjustment	±10 dB below 75 Hz
Mid-Bass Adjustment	-2 / 0 / +2 dB
Sensitivity	92 dB / 2.83 V / 1 m
Nominal Impedance	4 Ω
Impedance at 20 kHz	0.5 Ω
Recommended Amplifier Power	20 to 700 W per channel
Binding Posts	WBT-0703Cu nextgen 5-way
Crossover Components	Custom-wound transformer, air-core coils, polypropylene capacitors
ARC Connection	RJ45 / Mini USB
Maximum Power Draw	900 W per speaker
Standby Power Draw	<0.5 W per speaker
Height	69.8 in / 177.3 cm
Width	15.75 in / 40 cm
Depth	28.9 in / 73.3 cm
Weight	140 lb / 63.5 kg each

MartinLogan's current specifications confirm the 22 Hz to 21 kHz response, 92 dB sensitivity, 4-ohm nominal impedance, 0.5-ohm impedance at 20 kHz and dual 500-watt internal amplifiers.

MartinLogan Renaissance ESL 15A at The Grid HiFi

The Grid HiFi in Houston specializes in MartinLogan electrostatic loudspeakers and complete reference two-channel systems.

The Renaissance ESL 15A deserves to be designed as a complete system. Its electrostatic panel, 0.5-ohm high-frequency impedance, powered bass architecture and dipole radiation make amplifier matching, speaker positioning and room integration especially important.

We can match the Renaissance ESL 15A with appropriate reference amplification, configure its PoweredForce Forward bass system, perform ARC calibration, optimize panel placement and design the complete signal chain around the room.

That includes digital and analog sources, amplification, cabling, power infrastructure, equipment support, networking, speaker positioning and final system calibration.

Complimentary White Glove Delivery • Travel Reimbursement*
Qualifying purchasers may receive airfare reimbursement for your private audition.
Considering the Renaissance ESL 15A? Experience it properly before you decide. Call The Grid HiFi at (713) 218-8120 to arrange your private consultation.
*Restrictions apply. Contact us for details.