STAX SR-009 Earspeakers

Description

SR-009

The SR-009 are the product of STAX Audio’s repeated research into technology and materials. If a technology is not suitable for music, one should not adopt it. Even if it is high-tech.

A newly developed sound element has been adopted for the SR-009. New high polymer ultra-thin film material (called super engineering plastics) is employed for the diaphragm, delivering superior tone quality, excellent frequency characteristic, and a vast dynamic range.

New electrodes named MLER (Multi Layer ElectRodes) have been developed to realise the plane drive of the whole film diaphragm surface. While infinite thinness and flatness are required for the fixed electrodes, they simultaneously need to have other characteristics, for instance low resonance and high transmissivity of the sound wave.

Aluminium is a good material for sound and audio equipment in general, and SR-009 makes abundant use of it. Almost every part of SR-009 enclosure is manufactured through precise machine processing. High-quality copper wire of 99.9999% purity adopted for the cable, silver-coated and finished with the most suitable structure to drive the earspeaker.

The new design ear pads are individually made by craftsmen, and feature both real leather to cope with humidity, plus synthetic cushion material with moderate elasticity. The new ear pad enables hours of comfortable listening to music.

The headband (arc) is equipped with a 10-step position adjustment slider mechanism, and corresponds to an extremely wide range of cranial shapes.

Electrostatic technology

Electrostatic transducers consist of two parallel-arranged fixed electrodes with a very thin high-polymer film diaphragm sandwiched and suspended in the middle of the electrodes.

The diaphragm is supplied with the biasing voltage from the energising adaptors or from the driver unit.

When the fluctuating voltage of the audio signal is applied to the electrodes, the diaphragm is pulled by one electrode (which has the opposite charge of the diaphragm) and simultaneously pushed by the other electrode (which has the like charge of the diaphragm).

This continuous flow of alternating voltage causes the diaphragm to vibrate in faithful compliance with the amplifier output without lag, assuring undistorted sound waves. This is why the STAX electrostatic earspeakers sound so good.

Electrostatic driver required

Electrostatic reproduction has many quality advantages, however such units cannot be used directly with a conventional headphone jack, and require a special electrostatic amplifier (driver) unit.

The vibrating diaphragm requires Bias voltage of 580V (almost no current). Relatively high signal voltage to the fixed pole (up to 300-600V) must be supplied as push-pull, a rather special electrical signal. The STAX series of driver units are dedicated amplifiers strictly for STAX headphones.

Features

• New high-polymer diaphragm.
• Multi-layer electrode design.
• Precision machined enclosure.
• High-purity copper cable.
• Real leather ear pads.
• 10-step adjustable headband mechanism.

Specifications

• Type: Push-Pull Open Back Circular Electrostatic Headphone
• Frequency Response: 5 Hz – 42 kHz
• Electrostatic Capacitance: 110 pF (including cable)
• Impedance: 145 kω (including cable, at 10 kHz)
• Sound Pressure Sensitivity: 101 dB / 100 V RMS @ 1 kHz
• Maximum Sound Pressure: 118 dB / 400 Hz
• Bias Voltage: 580 V DC
• Channel Identification: L / R indicated on the arc assembly (inside head spring). Left channel cable is marked with a solid Line. Right channel is marked with a dotted Line.
• Ear Pads: Genuine Lamb Leather (direct skin contact), high-quality synthetic leather (surrounding portion)
• Cable: Silver-coated 6N (99.9999%) OFC parallel 6-strand, low-capacity special wide cable, 2.5 metre full length
• Weight: 1 lb (0.45 kg) without cable / 1.3 lb (0.59 kg) with cable

Full STAX Range Available

Unilet Sound & Vision are official retail partners for STAX Audio, providing sales, advice and assistance on their entire range of high-quality audio products. Please do get in touch if you would like a demonstration or wish to purchase.

More Information

• More about Electrostatics
• SR-009, by STAX Audio

Additional information

Brand

STAX

Founded in 1938, STAX brought the world's first electrostatic headphone to market in 1960. Today they continue their long tradition by offering the finest audio products for both professional and audiophile applications.

All STAX headphones are referred to as "earspeakers" - the company states that such ultra-high fidelity devices can only be compared with the best cost-no-object loudspeakers, not other headphones. Their unique amplifiers, earspeakers and drivers are highly sought-after products, and extremely well considered by aficionados in the audio industry.

Unilet Sound & Vision are one of the oldest STAX dealers in the UK, and one of the very few official outlets stocking their products. Do get in touch with us if you would like to audition the range, or need advice or assistance with choosing the right system for your needs.