Headphones — Stax SR-007S

The SR-007S is an open-back electrostatic headphone from Stax, built as the latest evolution of a design lineage first introduced in 1998. This model occupies an important position within Stax's current lineup, sitting well below the flagship SR-X9000 while incorporating refinements the brand originally developed for that statement design.

Key specs that matter

Frequency response is 6Hz to 41,000Hz. Electrostatic capacitance is 110pF including cable, with impedance at 145k ohms at 10kHz. Bias voltage is 580VDC Pro, a high figure requiring a dedicated Stax electrostatic amplifier or driver unit rather than a conventional headphone amplifier. Sound pressure sensitivity is 101dB at 100Vrms input. Weight is 430g. The push-pull electrostatic sound element uses newly redesigned large circular fixed electrodes with a 20% reduction in air vent hole diameter compared with earlier models, claimed to increase airflow and deliver smoother, more even frequency response. A stainless steel Anti-Resonance Structure adds genuine rigidity to reduce earcup resonance. Sheepskin earpads use a rotating design for improved comfort and fit, with a redesigned inner earpad refining sound absorption for a more expansive, precise soundstage. A detachable low-capacitance cable structure allows easy maintenance and future cable upgrades, a genuine departure from the fixed-cable designs of earlier SR-007 generations.

Sound and use context

Expect unparalleled detail, tonal accuracy and an expansive, precise soundstage - reviewers describe this as not simply a stripped-down flagship but a differently balanced interpretation of Stax's electrostatic philosophy, one that may represent the genuine sweet spot within the brand's entire headphone range for many listeners, delivering deep, resonant tones alongside heightened clarity.

Pairing

Because electrostatic headphones operate on a fundamentally different principle than conventional dynamic or planar magnetic designs, a dedicated Stax energizer or hybrid amplifier capable of delivering the 580V bias voltage and wide voltage swings is essential - a standard headphone amplifier cannot drive this headphone at all.

Alternatives

Stax's flagship SR-X9000 sits considerably above this model, incorporating the technology the SR-007S itself draws certain refinements from, worth the substantial further investment if this model's already exceptional performance still leaves ambitions for Stax's absolute current best.