ESL

About the ESL

The Quad ESL (Electrostatic Loudspeaker) is the world's first production full-range electrostatic loudspeaker, launched in 1957 by Quad Electroacoustics. It uses an ultra-thin electrically charged Mylar diaphragm suspended between highly charged stator elements to produce sound with extremely low distortion and fast transient response. The diaphragm is about ten times thinner than a human hair, resulting in minimal inertia and highly accurate sound reproduction. The speaker design includes multiple electrostatic panels with concentric rings of electrodes for pinpoint imaging and accurate stereo soundstage. The latest models, such as the ESL 2812 and 2912, feature improvements in power supply design to reduce charge creepage and enhance performance, especially in humid environments. The Quad ESL operates with a high voltage charge (up to 5kV or more) supplied to the stators, maintaining a constant charge mode for linear drive conditions. It is a dipole speaker radiating sound from both sides, eliminating enclosure colorations and crossover distortions. The speaker requires mains power to maintain the diaphragm charge and achieves best sound quality after a warm-up period. The Quad ESL is renowned for its clarity, lack of coloration, and ability to reproduce music with exceptional detail and minimal fatigue, making it a classic and highly respected HiFi product.