STAX 80th anniversary 3rd model
The SR-009 is a memorable model that appeared in 2011 and became the foundation of the present STAX flagship Earspeaker development. At that time this extraordinary Earspeaker attained a big success as the model that materialized the idea that has been embraced by STAX developers in pursuit of further improvement of sound quality. The memorable model that has achieved the highest peak sound of the STAX present new flagship SR-009S will soon be followed by the SR-009BK as the 80th anniversary limited model in special black color version. The SR-009BK in black finish is the limited production of 180 units in the whole world.

Notation of 80th anniversary
Anniversary model notation is printed at cable attachment part.

Limited serial number is adopted
Serial number label certificating 180-set limited production

“Super-engineering-plastics” diaphragm
The diaphragm material “super engineering plastic ” inherited by next higher rank models has been adopted for the sound unit. Materials excelled especially in tone quality have been selected for the extremely thin high polymer film diaphragm developed by refining the conventional engineering plastic, resulting in extremely excellent frequency characteristics from low to very high as well as vast dynamic range.

Multi-layer fixed electrode (MLER)
The fixed electrode that drives the whole diaphragm surface consists of three metal sheets unified through precision photograph etching processing on an atomic level using heat diffusion joint technology, which greatly improved the desirable electrode specifications such as planarity, low resonance and high sound wave permeability.

Tough machined aluminum chassis
Most part of the chassis is manufactured by precise machining to attain high-quality sound, rigidity and lightweight solution. The SR-009BK newly creates a sophisticated appearance along with the alumite-treated black color of the 80th anniversary special version.

Silver-coated high purity 6N copper wire
The high purity copper developed from necessity of large-scale integration wiring is also known as high-quality audio cable. The SR-009BK employs hybrid cable with 99.9999% (6 Nines) high-purity copper wires (φ0.14×3) at center and six silver-plated annealed copper wires (φ0.08×9) at its perimeter. The whole structure inherits the original broad parallel type which most fits the voltage transmission of electrostatic Earspeaker and reduces the capacitance between lines to the utmost limit. This further improved the “freshness of sound”.

Genuine leather ear pad
The SR-009BK employs a new design ear pad made by craftsman’s hand using both genuine sheep leather that keeps humidity environment good and sufficiently elastic cushion material. The ear pad fits well also for prolonged listening and keeps comfortable listening environment.

Ark assembly with 10-step click adjustment mechanism
The arc assembly features 10-step click mechanism for height adjustment. The optimal feeling of wearing is obtained also for the cranium with different size and form.


●Type: push-pull electrostatic, back open-air type enclosure
●Element shape: large circular sound element
●Fixed electrode: MLER (Multi Layer Electrode)
●Frequency response: 5 – 42,000Hz
●Electrostatic capacitance: 110pF
●Impedance: 145kΩ
●Sound pressure sensitivity: 101dB
●Bias voltage: 580V DC
●Cable conductor: 6N (99.9999%) OFC(φ0.14×3)+ silver-coated annealed copper wires (φ0.08×9)
●Cable configuration: parallel 6-strand, low-capacity special wide cable
●Cable length: 2.5m full length
●Ear pad: genuine sheep leather (skin touching portion), high-quality artificial leather (surrounding portion)
●Ear pad replacement: handled as repair service
●Weight: 454g (without cable),596g (including cable)