Quad ESL 2912 X Electrostatic Speakers

The founder of QUAD, Peter Walker, was a true visionary who revolutionized the world of hi-fi loudspeakers in the 1950s with the introduction of the first electrostatic loudspeaker. The ESL-57, the world’s first full-range electrostatic loudspeaker, marked a radical departure from conventional cone speaker designs.

Launched on the domestic hi-fi market in 1957, this innovative system used a thin electrically charged membrane suspended between stators to achieve extremely low distortion and remarkable transparency. The ESL-57 challenged established ideas about hi-fi sound reproduction. Since then, QUAD has continuously refined Walker’s design, building a reputation as one of the most prestigious audio brands and as the origin of one of the greatest hi-fi innovations of all time.

The New Quad ESL X Range

The ESL X concept emerged following extensive research by QUAD’s R&D team and its director Paul McConville (recognized as the world’s leading authority in QUAD ESL engineering, with 40 years of experience). Every aspect of the original design has been thoroughly evaluated and meticulously refined.

QUAD did not need to completely redesign its established methods. However, these incremental improvements have resulted in a significant transformation of the 2912 and 2812 models, giving rise to what is now known as the ESL X range.

Quad ESL 2912 X: Technology

It is easy to be familiar with electrostatic loudspeakers (ESL) without fully understanding how they differ from conventional speakers. It is important to state clearly that a QUAD ESL speaker is not an ordinary speaker. Unlike traditional designs using moving-coil drivers, the ESL operates on a completely different principle: an electrostatic panel.

At the core of a QUAD ESL speaker are cells containing an ultra-thin Mylar diaphragm, ten times thinner than a human hair. This Mylar film is coated with a high-resistance conductive material and suspended between two perforated metal plates called stators.

QUAD’s ESL mid-high panels feature concentric ring electrodes, a design originally developed for the revolutionary ESL-63. Instead of allowing uniform movement of all diaphragm sections, the speaker is precisely engineered so that the audio signal appears to originate from a single point in space. This point-source characteristic is optimized by an innovative delay-line system, which feeds the outer stator rings with progressively delayed versions of the audio signal.

The Mylar membrane is charged with a constant high voltage exceeding 5.2 kV DC. An audio signal is applied to the stators to create an alternating electric field, causing the charged membrane to move back and forth. The diaphragm vibrates precisely in response to the musical signal, producing the exceptional purity for which QUAD ESL speakers are renowned.

For the ESL X, QUAD uses audio transformers manufactured in the United Kingdom. These transformers are custom-designed with meticulous precision and undergo strict quality control by QUAD’s service team led by Rob Flain. They are specifically designed to improve signal dynamics, particularly in the midrange and treble, resulting in significantly greater detail and exceptional linearity.

The wide bandwidth ensures a flat response extending beyond 18 kHz, creating a sense of air and natural extension. Thanks to robust regulation, these transformers effectively eliminate flux modulation artifacts at high sound pressure levels. A key factor influencing ESL performance is its very high operating voltage, around 5,250 volts. This high voltage greatly improves diaphragm control and linearity while significantly reducing distortion. The ESL rigorously regulates this high voltage using a multiplier circuit that amplifies standard alternating current. This circuit is complemented by protection designed to prevent saturation (excessive input power), thus preserving the speaker from damage or distortion.

Quad ESL 2912 X: Implementation

The base of the speaker consists of a stand housing the electronics and crossover. At the rear of this base, there is a speaker terminal compatible with banana plugs or spades, along with an IEC C13 power input and a potentiometer to adjust the brightness of the “QUAD” logo.

The ESL 2912 X comes with highly effective decoupling spikes (and cups) as well as pads for delicate floors.

The ESL 2912 X is built using six electrostatic panels, making it the most advanced model ever offered by the manufacturer. It is therefore quite imposing with a height of 147 cm, yet remains easy to integrate and use in medium-sized living rooms.

Quad ESL 2912 X: Sound Performance

The ESL 2912 X is the largest ESL ever offered by Quad. It delivers the brand’s signature transparency and remarkable precision combined with striking naturalness. The midrange is so realistic that voices and acoustic instruments seem to originate directly from the room.

Thanks to its incredibly lightweight diaphragm, the 2912 X responds to transients with exceptional speed and precision. The stereo image is also outstanding, with instruments and voices appearing to float in space with a holographic effect.

The bass is impressive in scale, impact, and control. It clearly surpasses the 2812 X. The midrange benefits from exceptional clarity and extremely low distortion, while the treble stands out for its precision and smoothness. The frequency response is remarkable, especially in the bass, for a panel without a dynamic subwoofer: 28 Hz – 21 kHz (-6 dB).

With these ESL 2912 X, you get everything that made Quad panels successful, but with unmatched performance in terms of dynamics, transparency, and bandwidth.

They can be considered as large ESL-57 speakers. They retain the transparent, open, and airy sound of the ESL-57, but with significantly greater presence and detail. The dynamics and bass are at an unmatched level, even surpassing the excellent Quad ESL 2812 X. The stereo soundstage is also on another level, with low directivity and a much wider optimal listening area.

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