Stax’s SR‑007S headphones occupy a crucial position in the Japanese company’s lineup. Priced at US$2390, CA$2999, £2495, or €3000, these headphones sit well below the flagship SR‑X9000 headphones (US$6200, CA$8199, £5195, €7250), yet incorporate refinements derived from that statement design. S. Andrea Sundaram reviewed the SR‑007S headphones on SoundStage! Solo earlier this month after having evaluated the SR‑X9000 headphones last year, and that perspective proved essential: the SR‑007S design is not a stripped-down flagship, but a differently balanced interpretation of Stax’s electrostatic-headphone philosophy—one that may, for many listeners, represent the sweet spot in the company’s headphone range.
Unlike conventional dynamic or planar-magnetic headphones, the SR‑007Ses, like all Stax headphones, use an electrostatic driver in each earpiece. An electrostatic driver has an ultralight diaphragm suspended between charged electrodes and is driven directly by electrostatic force. Stax revised the SR‑007S electrostatic design relative to the previous SR‑007A model by reducing the size of the electrode perforations while increasing their number, claiming smoother airflow and frequency response. The stainless-steel anti-resonance structure (ARS) adds rigidity, and the sheepskin earpads fully encircle the ear. At 430g, these headphones are not exceptionally light, but S. Andrea found them very comfortable.
Electrical specifications are typical for a modern Stax design: 580VDC Pro bias, 145k ohms impedance, 110pF capacitance, and a rated frequency response of 6Hz–41kHz. Because electrostatic designs require specialized amplification, S. Andrea primarily used Stax’s SRM‑700T hybrid amplifier, which the company provided along with the SR‑007Ses. The SRM‑700T combines a solid-state input stage with a pair of 6SN7 output tubes. However, he also spent time driving the SR‑007Ses with his Woo Audio GES all-tube electrostatic amplifier. In the review he writes that with the Woo, the sound “was warmer, slightly rolled off at the top, softer in the bass, and less detailed, but still highly enjoyable.” But all his formal listening impressions in the review were based on the SRM‑700T driving the headphones. He felt that this amp provided greater clarity, extension, and control.
Using the Minnesota Orchestra’s recording of Beethoven’s Symphony No. 5, S. Andrea states in the review that the SR‑007Ses “have a more neutral tonal balance” than the SR‑X9000 headphones, with instruments sounding “closer to their true timbres.” He further notes that “when the cellos and basses enter with their jaunty run at about 1:45 in the [third] movement, there was great texture to the strings, but also enough body to support it.” He adds that although he “would’ve liked to hear a bit more of the basses,” he still “appreciated how incredibly clean they sounded, with the individual notes clearly discernible and possessing a lively, bouncy feel.” Still writing about this recording, he says that he could hear “extra treble energy that put a subtle sheen on upper woodwinds and gave brass instruments a little added brilliance, as if their bells were made of a slightly thinner metal than usual.”
S. Andrea describes Valery Gergiev’s performance of Rimsky-Korsakov’s Sheherazade with the Kirov Orchestra as “a less neutrally balanced recording,” pointing out: “Played through loudspeakers or headphones generally regarded as neutral, both the upper strings and brass come across a little too aggressively in this recording—especially in the louder sections. The SR‑007Ses certainly let me hear those foibles, but didn’t exacerbate them to the point of rendering the recording unlistenable, as can sometimes happen when recording and transducer have similar vices.”
Next some jazz: Diana Krall’s Live in Paris, and specifically “’Deed I Do,” which demonstrated the headphones’ tonal balance and control. “There was enough of John Clayton’s upright bass to balance the rest of the group,” S. Andrea writes, noting that Anthony Wilson’s “guitar was wonderfully articulate, with a good blend of attack and note body, and Krall’s piano was well balanced from top to bottom. Krall’s voice had a touch of extra sibilance, but Jeff Hamilton’s brushwork on the snare sounded like brushes, not static.”
He carries on describing the sound with another jazz album, Count Basie’s Chairman of the Board. On the track “Speaking of Sounds,” S. Andrea states that he heard the classic early-stereo “three distinct islands of sound” presentation—woodwinds left, brass right, rhythm section center—each with distinct ambience, which the Stax headphones allowed him to easily pick out. He then describes “hearing the reverb of the trumpet solo in the right image, then fractionally delayed in the center image” with the utmost clarity through the SR‑007Ses. In fact, the sonic result was so precise, it made him wonder “about exactly how the microphones had been set up and what the recording engineers may have been using as a reverb chamber.”
Dense productions were handled with notable insight. Listening to Leonard Cohen’s Death of a Ladies’ Man, S. Andrea describes how the SR‑007Ses separated Cohen’s voice from Phil Spector’s thick wall-of-sound backdrop more effectively than his reference Audeze LCD‑X planar-magnetic headphones. On “Memories,” the saxophone solo occupied its own clearly defined acoustic space, complete with distinct reverberation character. S. Andrea then states: “If you want to hear how a recording was put together, few headphones will give you more insight than the SR‑007Ses.”
Bass performance remained the principal concern—these headphones “definitely prioritize tunefulness and articulation over bass quantity,” S. Andrea points out. On Kendrick Lamar’s “DNA” from Damn, the intentionally distorted low frequencies were rendered with crystal clarity but without the physical weight some listeners might expect. He concluded that the SR‑007S headphones emphasize articulation and tonal precision rather than visceral slam.
Throughout the review, Sundaram primarily compared the SR‑007S headphones with the SR‑X9000 headphones, though from memory and detailed listening notes. S. Andrea notes that the flagship design extracted even greater microdetail and created a larger, more immersive acoustic envelope. He says the SR‑X9000s probably reached deeper in the bass, but adds, “neither pair of headphones will satisfy bassheads, though.” Mind you, he also notes that the tonal balance of the SR‑007S headphones seemed closer to neutral than what he remembers the SR‑X9000s being.
He also compared the SR‑007Ses to his Audeze LCD‑X headphones, which cost about half as much. He praises the Audeze planars, describing their soundstaging as not being “radically different” from the Stax electrostatics, but having a “denser, weightier sound.” In the most telling part of the comparison, S. Andrea states that the “Audezes are clear and detailed compared to most conventional headphones, and even compared to many other planar-magnetic designs, but they can’t match the SR‑007Ses in that regard.”
S. Andrea outlines some caveats to the SR‑007S headphones, such as the requirement for a dedicated electrostatic-headphone amplifier. And headphones such as these might not satisfy listeners who demand heavy, physical bass impact. But for those seeking the distinctive effortlessness and resolution that electrostatic designs can provide, the SR‑007S headphones offer an unusually compelling entry point.
While Stax’s SR‑X9000s remain technically superior in some respects, the SR‑007S headphones may be the more rational choice for many listeners—not because of the much lower price but because of their more compact dimensions and compelling sound. S. Andrea advises: “If you are curious about what electrostatic headphones have to offer, the SR‑007Ses are the ones to audition.”
His praise earned these headphones high marks for sound quality—9.5 out of 10—and a Reviewers’ Choice award when the review was published. This month, based strictly on sound quality and long-term reference potential, the Stax SR‑007S headphones receive a Recommended Reference Component award.
Manufacturer contact information:
Stax International
Room 2101, 21st floor, The L. Plaza,
367-375 Queen’s Road,
Central - Hong Kong
Phone: +852 2522 6989
Fax: +852 2522 1989
Email: enquiry@staxheadphones.com
Website: www.staxheadphones.com
