Quad ESL-2812X Floorstanding Speakers

The QUAD ESL X: A Legacy of Sound

The Beginning

The ESL X concept was born in 2019 out of a comprehensive review of the QUAD Electrostatic manufacturing facility, which is exclusively dedicated to producing QUAD ESL loudspeakers. Under the leadership of Paul McConville, a world-renowned authority in QUAD ESL engineering with 40 years of experience, every aspect of the original design was meticulously refined.

The process involved a detailed analysis of every step, material, tool, and technique used in constructing a QUAD ESL, with the goal of improving the quality and precision of the speaker's assembly. Using techniques like advanced laser-precision metrology, QUAD conducted a thorough review of the fundamental ESL design.

This led to systematic enhancements in the spraying, etching, tensioning, and assembly processes, ensuring peak performance. Significant upgrades were also made to both passive and active components, enhancing the overall integrity of the ESL 2912 and 2812 models. The results of this extensive audit were so significant that the engineering team felt it warranted a new model in the ESL lineage, leading to the creation of the ESL X.

It’s widely accepted that enhancing an electrostatic loudspeaker (ESL) is about making incremental improvements rather than radical overhauls. While QUAD didn't need to completely rebuild their methods, these advancements have culminated in the significant transformation of the 2912 and 2812 models into the ESL X.

The History

In 1957, QUAD founder Peter Walker broke new ground with the introduction of the first full-range electrostatic loudspeaker, which achieved a level of transient response and clarity previously considered impossible. Subsequent models—the ESL-63, ESL988/989, ESL 2805/2905, and ESL 2812/2912—each introduced incremental refinements. These models have long been celebrated by critics for their airy, effortless midrange and natural, "box-less" sound.

The Heart of the ESL

Unlike typical speakers that use moving-coil drivers, a QUAD ESL operates on a completely different principle: an electrostatic panel. At its core are panels that contain a diaphragm of fine Mylar film, which is ten times thinner than a human hair. This Mylar film is coated with a high-resistance conductive material and is suspended between two perforated metal plates known as stators.

Because the diaphragm is so light, it's incredibly responsive—far lighter than any conventional speaker cone. This allows it to respond to audio transients with remarkable speed and accuracy. The Mylar diaphragm is charged to a constant high voltage of over 5.2 kV DC. When an audio signal is applied to the stators, it creates an alternating electric field that pushes and pulls the charged Mylar diaphragm. This vibration precisely follows the music signal, producing the ultra-pure sound for which QUAD ESL speakers are famous.

Due to the diaphragm's lightweight nature and uniform drive across its entire surface, the sound it generates is exceptionally clean with very low distortion, especially in the midrange frequencies where the human ear is most sensitive.

Point Source" Design

QUAD's mid-high frequency panels feature a "concentric ring" electrode design, a concept first introduced with the groundbreaking ESL-63. This sophisticated design ensures that the audio signal appears to emanate from a single point in space. The result is an exceptionally precise stereo image where instruments and vocals seem to hover within the listening environment, creating an immersive experience. This "point-source" characteristic is made possible by an innovative delay line system that supplies the outer rings of the stators with a slightly delayed version of the audio signal.

High Voltage & Low Distortion

A critical factor in the ESL's performance is its high operating voltage, which is approximately 5,250 volts. This elevated voltage gives the diaphragm superior control and linearity, allowing it to move with precision and significantly reducing distortion. The QUAD ESL regulates this high voltage using a multiplier circuit that amplifies standard AC power. A protective circuit is also included to prevent overdriving, which safeguards the speaker from potential damage and distortion.

The Improvements: Taking It to the "X" Level

The ESL X's refined manufacturing process is a key part of its improved performance. The time it takes to build a single QUAD ESL panel has been extended, and the overall assembly process is marked by extreme care and attention to detail.

However, the major upgrades for the ESL X are far more technical:

• Modular PCB Design: The operational printed circuit board (PCB) has been split from a single, monolithic design into three separate, independent modules: a High-Voltage Multiplier Module, a Control and Protection Module, and a Low-Voltage Signal Module. By physically separating the high-voltage (5.25 kV) multiplier stage from the sensitive low-voltage circuits, QUAD significantly reduces stray electric fields. This isolation minimizes interference and crosstalk, enhancing stability and noise performance. The result is a crystal-clear audio signal that reveals every musical detail, even during powerful peaks.
• UK-Manufactured Audio Transformers: For the ESL X, QUAD has returned to using meticulously custom-designed audio transformers made in the UK. These transformers, refined and quality-controlled by QUAD's renowned service team, are engineered to improve signal dynamics, especially in the mid and high frequencies. This results in a much more detailed and linear sound. The wide bandwidth ensures a flat response beyond 18 kHz, creating a sense of airiness and extension. These robust transformers also eliminate flux modulation artifacts when operating at high sound pressure levels. Ultimately, they enhance mid-high dynamics, sharpen transient attacks, and broaden the perceived depth of the soundstage with superior resolution of micro-dynamics.

We endeavour to despatch same day for orders placed up to 1pm on available stock items (items with stock message "Usually dispatched within 24 hours"). Please remember to check with us first for a physical stock check if next day delivery is important to you. Any items with stock message "Usually dispatched within 72 hours" are items that we do not hold in stock but order in from the importer or manufacturer as soon as a customer order is received. Occasionally these may be delayed beyond 72 hours due to importer/manufacturer stock levels but we will inform you as soon as we can if this is the case.

UK Orders

We despatch the bulk of our UK mainland items on a 24 hour service – Free of Charge. Non Mainland locations - Isle of Man, Isle of Wight, the Scilly Isles, the Scottish highlands and Islands, the Channel Islands and Northern Ireland may take a day or so longer and are not Free of Charge. Smaller items are delivered using Royal Mail 24 or special delivery. Larger items are delivered using a courier service such as DPD or UPS.

International Orders

Due to the nature of our products and brand restrictions we are only able to send certain items internationally. Smaller items are delivered using Royal Mail Small Packets Airmail with International Tracked and/or Signed depending on value of item and availability of the service. Larger International shipments are sent by insured and tracked services using UPS. If there are any delays due to specific customs regulations, etc, you will be contacted by Hifisound or by the courier with a request for any further information required. Customs duties can apply for shipments to any countries outside of the UK depending on where the product you have bought is made. Customers are responsible for all taxes and duties incurred when the items enter their country.

Collect in Store or Home Install

At the request of the manufacturer some items cannot be supplied by mail order but you can click and buy them and then elect to collect them from our store or arrange a home install (if applicable). Applicable items clearly state that they are Collect in store or home install. Once ordered you will receive a message prompting you to contact us by phone or email to arrange for us to deliver and install or to reserve and collect from our store at your convenience, you will also be advised of the delivery time / stock availability as not all Home install / collect in store items are held in stock.