A hybrid electrostatic floorstander, supplied as a pair: an XStat CLS panel 33 cm wide and two 25.4 cm aluminium woofers, each with its own 300 W Class D stage. The bass section is run by a 24-bit DSP and is ARC ready.
Expression ESL 13A: what is inside
The Expression ESL 13A sits in the middle of the powered-bass Masterpiece floorstanders. Compared with the model below it, both the panel, at 112 x 33 cm and 3,696 cm² of radiating area, and the woofers, now 25.4 cm, are larger. The two sections hand over at 300 Hz. Stated figures are 24-23,000 Hz within ±3 dB and 91 dB sensitivity, with an external amplifier of between 20 and 600 W per channel suggested.
The panel is built as a sandwich: a very thin film, vacuum bonded between two perforated MicroPerf stators whose fine hole pattern uncovers almost double the surface of a conventional panel of that size. ClearSpar spacers keep it taut without spoiling the see-through look. The slight horizontal curve, which gives Curvilinear Line Source its name, widens the useful listening area at high frequencies; dipole radiation limits reflections from the side walls and makes use of the rear one instead.
Below, the two woofers work in independent closed volumes, one at the front and one at the back, and the PoweredForce Forward system offsets their output in phase to reduce the energy thrown back by the wall to the rear: about 25 cm between cabinet and wall is enough, while the panel asks for about 75. With the optional microphone kit, ARC correction fits the bass to the room. The rear plate carries the bass and mid-bass adjustments and the LED light dimmer; the terminals are pure-copper WBT.
Specifications
- Frequency range: 24-23,000 Hz (±3 dB)
- Sensitivity: 91 dB (2.83 V at 1 m)
- Impedance: 4 ohms nominal, 0.7 ohms at 20 kHz
- Suggested amplifier: 20 to 600 W a channel
- Crossover point: 300 Hz
- Horizontal spread: 30°
- Electrostatic panel: XStat CLS, 112 x 33 cm, radiating area 3,696 cm²
- Woofers: two 25.4 cm aluminium units on cast baskets, in independent closed volumes
- Bass amplification: two Class D stages of 300 W into 4 ohms (600 W peak)
- Processing: 24-bit DSP preamplifier for the woofer section
- Room correction: ARC ready, measurement kit bought separately
- Adjustments: bass ±10 dB below 75 Hz, mid-bass -2/0/+2 dB, ARC engaged or bypassed
- Lighting: LED with three levels, full, dimmed, off
- Terminals: WBT-0703Cu nextgen in gold-plated pure copper
- Other sockets: mains, RJ45 and mini USB for ARC
- Size (H x W x D): 156.1 x 33.9 x 69.9 cm
- Weight: 46.8 kg each
- Supplied: sold as a pair
- Finishes: gloss black, basalt black, gloss white, cherry, walnut, silver, burgundy, dark blue, Desert Silver, grey, red
