Features
| Removable Grill | Yes |
|---|---|
| Warranty length | 5 Years |
| Brand | Martin Logan |
Tech Specs
- Frequency Response: 24–23,000 Hz ±3dB
- Recommended Amplifier Power: 20—600 watts per channel
- Horizontal Dispersion: 30°
- Vertical Dispersion: 44" (112cm) line source
- Sensitivity: 91 dB/2.83 volts/meter
- Impedance: 4 Ohms, 0.7 at 20kHz Compatible with 4, 6, or 8 Ohm rated amplifiers.
- Crossover Frequency: 300Hz
- High Frequency Transducer: XStat™ CLS™ electrostatic transducer » Panel Dimensions: 44" x 13" (112 x 33cm) » Radiating Area: 572 in² (3,696 cm² )
- Low Frequency Transducer: Two 10” (25.4 cm) cast basket, high excursion, rigid aluminium cone and extended throw drive assembly, non-resonance asymmetrical chamber format.
- Amplifier: Woofer: 2 x 300 watts/channel (4 ohms), 2 x 600 watts peak
- Room Correction (Bass Section): Anthem Room Correction (ARC™) ready (Sold Separately)
- Components: Custom-wound audio transformer, air core coils, polypropylene capacitors. 24-bit DSP based preamplifier (used with woofer amplifier).
- Audio Controls: Bass: ±10 dB under 75 Hz Mid-Bass: –2 dB, 0 db, +2 db Light: On, Dim, Off ARC™ Room EQ: On, Off
- Signal Inputs: WBT-0703Cu nextgen™ 5-way binding posts feature a filigree signal conductor made from gold plated, nickel free, non- ferromagnetic, pure copper for high conductivity and fully insulated. Free from eddy current effects.
- Inputs: AC Power, RJ45 (for ARC), mini USB (for ARC)
- Power Draw: Idle: < 1W/channel Max: 500W/channel
- Lighting: LED intensity control: on, dim, off
- Weight: 103 lbs. (46.8 kg)
- Dimensions: 61.5" x 13.4" x 27.5 " (156.1cm x 33.9cm x 69.9cm)
Product Description
Martin Logan Expression ESL 13A active electrostatic speakers are a step up from the ESL 11A and feature a 13” Xstat electrostatic transducer as well as two PoweredForce 10” woofers.
The panel is powered by dual 300 watt class D amplifiers and sound is enriched by a 24 bit Vojtko designed DSP engine as well as ARC room correction.
ESL 13A are designed to reveal the true emotion of the music. Advanced airframe panel mounting uses aerospace grade aluminium and the curvilinear shape is designed to improve high frequency dispersion.
Large 10” dual PoweredForce woofers
The two 10” woofers used by the ESL 13A feature low-distortion aluminium cone drivers. Notably, they also fire to the front and rear, the same as the dipole, electrostatic panel. The woofers are mounted in individually enclosed compact chambers.
Exclusive PoweredForce technology is used to control the interaction between the rear firing bass driver and the wall behind. PoweredForce, prevents boominess, by using smart phase-shifting logic to stop any sound from bouncing back into the room. The result is realistic bass in any location. PoweredForce also uses an advanced crossover, to minimise reflected energy. This gives more placement flexibility.
MicroPerf stators
Advanced MicroPerf stator technology gives almost twice the radiating area of the diaphragm, compared to a traditional panel of the same size. ClearSpar spacers are used, which keep the panel rigid and are almost visually transparent. An electrostatic panel is made up of two stators or grids to either side of a diaphragm. The plates are charged to a high voltage and the diaphragm is the part that produces the sound.
Airframe panel mounting
Not only is the Expression 13A beautiful, but the Aerospace grade aluminium Airframe makes the panels extremely rigid. The styling of the Airframe never obstructs the playable surface or interferes with the dipole sound radiation pattern. It also provides electrical and acoustic isolation. This has the effect of minimising intermodulation distortion. The distortion is caused by vibration and resonance. Finally, the curved shape also aids with high frequency dispersion. As a result, low-level sonic detail is enhanced
Dipole dispersion of sound
One unique feature of an electrostatic speaker is its dipole characteristic. The sound heard from a loudspeaker is a combination of direct sound, from the driver, and any reflections from the wall. The mistiming of this information can mask detail. On the other hand, electrostatic speakers emit sound from both the front and back. However, these signals are antiphase. The result is that, towards the edges, the signals cancel out. The result is no sound from the sides, to muddy the audio.
Class D amplifiers
The ESL 13A features two powerful 300 Watt Class D amplifiers. These are almost 90% efficient, with little heat generation, and a compact form factor. Class D amplifiers are digital in nature. The output consists of a series of high frequency pulses. This is known as pulse code modulation. The output transistors are usually fast switching Mosfets. Finally, the crossover is also voiced by Vojtko, and uses hand built air-core coils and audio grade polypropylene capacitors. This provides vanishingly low distortion.
Active room correction.
ARC stands for Anthem Room Correction and is a way to actively compensate for the room's walls and furniture. Your listening room will be unique and hence needs a unique equalization curve to compensate for the shape and contents. For example, bass frequencies can do unpredictable things, resulting in muddy sound and a reduced soundstage. The ESL 13A has a microphone input and the ARC microphone is used to monitor from the listening position. The internal DSP software then compares the sound with an ideal response curve and corrects the response This is done in real time. The sound should have a natural sounding bass, without anomalies caused by your room.
Sophisticated audio processing and control, with the DSP engine
ESL 13A uses a sophisticated sound control system. DSP stands from Digital Sound Processing. DSP has complete control, and performs constant optimization of the sound. The software was designed by Vojtko and uses 24-bit technology. The result is sound that goes down to 22Hz and has instant response, which performance that should be close to lifelike sound imaging without colouration.
