STAX History of Earspeakers

Stax Industries, Ltd, is japan's oldest and most honored manufacturer of specialized audio equipment. In 1959 Stax developed the world's first electrostatic headphone - marketed the following year as the SR-1.  [Today] Thirty years later, president Naotake Hayashi and his son Takeshi Hayashi continue their tradition by offering the finest headphones for both professional and audiophile applications. Stax prefers to call its headphones "Earspeakers"; such Ultra-High Fidelity devices for reproducing music can only be compared with the best cost-no-object loudspeakers, not other headphones. The term "Earspeaker" is therefore more descriptive of Stax's contribution to today's most advanced level of sonic transduction.

The Stax philosophy revolves around a single tent; the more precisely the reproduction mirrors the original live sound, the more clearly one may grasp the soul of the musical composition and performance. With this belief constantly in mind, Stax strives to make products providing the highest performance, reliability and value.

The most advancedd product of the Stax Industries, are:

Stax SR-Γ Series (Pro);

Stax SR-Σ Series (Pro);

Stax SR-Λ Series (Professional and Signature);

And SR-X, SR-5, SR-84 or SR-34

How Electrostatic Earspeaker Works

If we speak of a headphone, it usually means a dynamic one employing a dynamic transducer. In the dynamic transducer the driving force is applied only to the one part of the diaphragm which, therefore, must be stiff enough not to be deformed by air load. However, stiff materials considerably increase the diaphragm mass resulting in significant deterioration of transient response. In addition, the ununiform force applied over the diaphragm area leads to ehat is called "cone break-up". Hysteresis distortion caused through the magnet inevitable in the dynamic transducer cannot be ignored, either.

The electrostatic transducer adopted in the Stax earspeakers consist of two parallel-arranged fixed electrodes and several microns thick (2 microns in the SR-Sigma, the SR-lambda,the SR-X/Mk3 and the SR-5N. 6 microns in the SR-84 and the SR-34) high-polymer film diaphragm suspended in the middle of the electrodes. The low-mass film diaphragm is supplied with the biasing voltage from the energizing adaptors or from the SRM-1/Mk2. In the electret type earspeakers like  the SR-84 and the SR-34 the diaphragm is permanently charged minus. When the fluctuating voltage of the audio signal is applied to the electrodes, the diaphragm is pulled by the electrode which has the opposite charge of the diaphragm's and simultaneously pushed by the other electrode which then has the like charge of the diaphragm's. the continuous flow of alternating voltage in interpretation of audio signals causes the diaphragm to vibrate in faithful compliance with the amplifier output without time lag, assuring undistorted sound waves. This is why the Stax electrostatic earspeakers sound so good. The figure above shows the driving mechanism of the SR-84 and the SR-34.