Наушники — Stax SR-009D

The SR-009D is a reissue of the SR-009 electrostatic earspeaker that Stax first launched in 2011 and later stopped making. Stax announced the new version on 27 November 2025 with shipping from 3 December 2025 at USD 2,890 in North America, a lower price than the original carried at launch. Changes against the old model cover the body colour, cable material and unit case, and the D version returns to the stainless steel electrodes of the SR-009 rather than the gold-plated ones of the SR-009S.

Key specs that matter

The SR-009D is a push-pull electrostatic design with a large round element in an open-air enclosure. Frequency response is 5 to 42,000 Hz, capacitance is 110 pF and impedance is 145 kohm. Sensitivity is 101 dB, and maximum sound pressure is 118 dB at 400 Hz. The diaphragm needs a 580 V DC bias. The earspeaker weighs 452 g without its cable. The cable is 2.5 m long, uses OFC conductors and is built as a wide, low-capacitance parallel cable with six strands.

Engineering and use context

The fixed electrode uses MLER, or Multi-Layer Electrode, technology. Three photo-etched stainless steel plates are joined at the atomic level by thermal diffusion bonding in a vacuum, with no adhesive, which Stax says gives high flatness, low resonance and good passage of sound waves through the electrode. The original SR-009 had a heavy all-aluminium frame, while the D version uses an injection-moulded unit case to reduce weight. The headband now has a ten-step click adjustment in place of the old friction slider. The cable is detachable and replaceable, a structure Stax now uses across its current range, so it can be swapped for maintenance or a later upgrade. Earpads are sheepskin leather on the contact surface with artificial leather around it, and an aluminium carrying case comes in the box.

Pairing

Like every Stax earspeaker, the SR-009D cannot be used with an ordinary headphone output. It needs a dedicated driver unit, often called an energizer, that supplies the high drive voltage and the Pro bias. Stax offers several drivers for this, from the tube hybrid SRM-500T to the SRM-700S and SRM-700T pair, all with Pro-bias sockets. Stax positions the SR-009D as an entry point to its high-end electrostatic models.

Alternatives

Above it in the Stax earspeaker range sits the SR-X9000, which uses the four-layer MLER-3 electrode and a diaphragm with 20% more area than the SR-009S.