Напольная акустика — QUAD ESL 2812X

The ESL 2812X is a floorstanding full-range electrostatic loudspeaker from QUAD, built as a dipole with four electrostatic drive membranes and a fixed backward tilt of 3 degrees. It shares its treble and midrange panels with the larger ESL 2912X, and its lower height makes it the easier of the two to place. The UK price is GBP 10,999 per pair, and finish is matt black with an optional LED halo lighting feature.

Key specs that matter

QUAD rates response at 37 Hz to 21 kHz at the -6 dB points, with usable output from 33 Hz to 23 kHz. Sensitivity is given as 1.5 mbar per volt at 1 m, equivalent to 86 dB for 2.83 V. Nominal impedance is 8 ohms, varying between 4 and 15 ohms across the band. Maximum output is 2 N/m2 at 2 m on axis. QUAD states that the wide bandwidth keeps response flat to beyond 18 kHz. Distortion at 100 dB and 1 m stays below 0.15% above 1 kHz, below 0.5% above 100 Hz and below 1.0% above 50 Hz. Each speaker measures 1070 x 690 x 380 mm tall, wide and deep respectively, and each unit weighs 35 kg net.

Engineering and use context

Each panel uses a thin conductive Mylar film diaphragm suspended in an electrostatic field between two stators. Concentric rings driven with progressively increasing delay give point source behaviour, so the membrane radiates as if from a single point behind the panel. The panels are held in a heavy duty composite aluminium and steel chassis. For the X generation QUAD split the electronics into three independent PCB modules - a high voltage multiplier, a control and protection board and a low voltage signal board - which physically separates the roughly 5,250 V EHT stage from the lower voltage circuits. Audio transformers are once again made in the UK and custom specified for this design. Each speaker needs mains power, accepting 220-240 V or 100-120 V, drawing 8 W and protected by a 100 mA or 200 mA anti-surge fuse. QUAD backs the model with a 3-year warranty.

Pairing

Input limits guide amplifier choice. The ESL 2812X accepts 10 V rms continuously, a 40 V programme peak before output distorts, and 55 V as the permitted peak input, so an amplifier able to swing well beyond those figures should be operated with care. A stable solid-state or valve design comfortable with a load that falls to 4 ohms suits the panel, and the dipole rear wave calls for space behind the speaker.

Alternatives

The QUAD ESL 2912X uses six panel elements in a 1470 mm tall frame with response extending to 32 Hz at -6 dB.