Features
| Warranty length | 3 Years |
|---|---|
| Brand | Martin Logan |
Tech Specs
- Frequency Response: 34–23,000 Hz ±3dB
- Recommended Amplifier Power: 20—400 watts per channel
- Horizontal Dispersion: 30°
- Vertical Dispersion: 44" (112cm) line source
- Sensitivity: 90 dB/2.83 volts/meter
- Impedance: 4 Ohms, 0.8 at 20kHz Compatible with 4, 6, or 8 Ohm rated amplifiers.
- Crossover Frequency: 380Hz
- 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
- Components: Custom-wound audio transformer, air core coils, low DCR steel laminate coils, polyester capacitors
- Signal Inputs: Custom 5-way bi-wire tool-less binding posts
- Power Draw: Max: 2W per channel Standby: <1W per channel
- Weight: 78 lbs. (35.4 kg)
- Dimensions: 59.8" x 10.4" x 25.4 " (152cm x 26.4cm x 64.6cm)
Product Description
Martin Logan Classic ESL 9 electrostatic speakers sit in the middle of the range and are an excellent choice featuring a 9.2” CLS Xstat panel, two 8” aluminium coned woofers and 5-way bi-wire binding posts. The heart of the speaker is the 9.2” curvilinear panel – the curved shape helps with sound dispersion and improves the listening angle. Opposing woofers reduce vibration and a Vojtko designed crossover is used, for precise bass. Aerospace grade aluminium Airframe resists vibration.
Curvilinear electrostatic panels
The curved panel is more than just beautiful. The curvilinear shape performs an important function. Previously electrostatic panels had a narrow listening angle. This was known as the ‘beaming’ effect. To mitigate this Martin Logan developed the curvilinear shape, that now produces a wide sound field.
Notably, the Xstat transducer also uses MicroPerf stators. The ESL 9 uses two stators on either side of the diaphragm. The stators are charged to a high voltage and are used to generate the sound. The MicroPerf holes provide a larger diaphragm area for more sound output.
Controlled dispersion sound radiation
The Martin Logan ESL 9 panel has some unique characteristics. These are used to good effect. One of them is the controlled dispersion of sound. As a result, the sound is less blurred and has better stereo imaging. The sound from most speakers is a combination of direct sound from the drivers and reflected sound from the room. Reflected sound can come from the walls as well as any furniture in the room.
However, electrostatic panels produce less sound from the sides. Therefore, there are no room reflections to blur the detail. The panel is bipolar with sound coming from the rear. This has the effect of increasing ambience, especially in the mid-range
Ultra-rigid Airframe
With the ESL 9, the panel is mounted in a rigid Aerospace grade aluminium Airframe, this provides a rigid mounting for the panel and helps to reduce vibration. It also reduces intermodulation distortion. Additionally, ClearSpar spacers are used, that do not obscure the diaphragm. This makes the panel almost transparent.
Dual 8” woofers
Two woofers are provided one firing forward and one firing backwards. This mimics the bipolar output of the electrostatic panel. The ESL 9’s woofers feature low distortion and high-excursion aluminium cones and sit in a beautifully sculpted enclosure. Having opposing woofers greatly reduces vibration for accurate and punchy bass. There is also an ultra-low turbulence, rear firing slotted, bass port that increases the deep bass output.
Advanced topology crossover.
The advanced Vojtko designed crossover provides good bass control and is carefully hand built using only the best components. For example, the air-core coils use low DCR steel. Additionally, audio grade metalized film capacitors are used. The proprietary crossover topology provides vanishingly low levels of distortion, for a full and warm sound.
PoweredForce bass precision
The ESL 9’s have a carefully designed bass enclosure that maximises the benefits of the woofer layout. The result is very precise low frequency sound. Martin Logan uses ForceForward technology to enhance the ultra-low band. This is done by tuning the phasing of the output from both woofers. This has the effect of cancelling out any errors, due to the bass frequencies bouncing off the wall behind the speaker.
How do electrostatic speakers work?
There are three main elements to an electrostatic speaker. The diaphragm, the stators or grids and the coupling transformers. The diaphragm is the part that produces sound, by moving air. It is made of a type of plastic, usually PET film. This is sandwiched between two stators. With the ESL 9, the stators are full of MicroPerf holes. This allows the sound to pass through. The stators are also charged to a high voltage, as is the diaphragm.
Next, the audio signal is fed to the stators, causing the diaphragm to vibrate with the music. The sound is bipolar meaning that it comes from both sides of the panel. Finally, electrostatic panels are high impedance devices. This requires that a matching transformer is used so that they can be used with conventional 4 - 16 Ohm impedance amplifiers.
