Sound element with new fixed electrodes
If the fixed electrode becomes infinitely thinner, the air resistance will be decreased and the permeability of sound waves will be improved. On the other hand, thinner electrodes are poor in rigidity and suffer from vibrations of their own and the sound becomes muddy.The SR-009S evolved further the electrode established in the SR009 as the integration of present technology.
The edges of electrode hole were smoothed through after-etching processing to reduce air resistance, and the permeability of sound has been much more improved. Moreover, gold plating processing with large specific gravity further decreased the electrode vibration. Finally, the sound clarity has been achieved by reducing the resistance of electrode itself.

Tough solid aluminum chassis 
It employed secures firmly the sound element, contributing to improve the clearness of sound. Furthermore, the case thickness has been reduced to the limit, making the flow of condensation-and-rarefaction air wave from the sound element more smooth.

New designed guard mesh
Intensity has been increased by giving roundness to the “guard mesh” of sound element, which lowered the influence of reflection and improved the resolution of sound.

About Stax Headphones

Stax produce exclusively electrostatic headphones, or “earspeakers” as they call them, in Japan, since 1938.  Stax chose the electrostatic technology for its ability to produce transparent sound, and low weight for comfort/ergonomics, both due to the driver design not employing fixed magnets and moving coils, as opposed to other common headphone driver designs. The minimal weight of the driver ensures a very quick response to the signal, creating a more faithful sound reproduction.

The electrostatic driver creates sound when it is powered by static charge (bias voltage), which reacts to a high voltage signal field created around the driver element by the stators. For this reason, all electrostatic headphones require special amplification to supply the high voltage (DC) bias, and high voltage (AC) audio signal. In the case of modern Stax headphones, that DC bias is 580V. Stax manufactures a number of dedicated amplifiers for their headphones, ranging from a relatively small portable model, SRM-D10, to their flagship SRM-T8000.

Our Take

With improved bass response and a tamed treble peak relative to the original SR-009, the SR-009S is Stax’ latest effort to produce the world’s best headphone.  With updated drivers, pads, and other housing pieces, the SR-009S is a step forward while still retaining much of the look and character of the original. Of course we recommend our Blue Hawaii SE amplifier in order to get the highest level of sound performance possible from these amazing headphones.