Electrostatic implementation is still the benchmark in headphone listening, and the STAX SR-007S is a solid reminder why. This latest update in the SR-007 line (which includes the SR-007A and SR-007MK2) focuses on refined electrostatic technology with updated diaphragms and redesigned electrodes for clearer, more detailed sound. The Anti-Resonance Structure (ARS), inspired by the SR-X9000, reduces vibrations and improves rigidity for a cleaner audio profile. With comfortable sheepskin earpads and a durable detachable cable, the SR-007S offers a thoughtful balance of performance and practicality.
What Are Electrostatic Headphones?
An electrostatic headphone uses drivers similar to those used in electrostatic speakers, but on a much smaller scale.
An electrostatic driver for headphone applications employs a very thin diaphragm that is placed between two perforated metal plates. The diaphragm holds a constant electrical charge as a result of a conductive coating. The membrane is firmly attached in place with “spars” that allow it to move back and forth freely to produce sound.
There are more details, but this gives you a basic idea of how electrostatic drivers work in headphones. Electrostatic drivers support exceptional accuracy, very low distortion, and respond quickly. However, to operate electrostatic headphones, an external amplifier (sometimes referred to as an energizer) is needed that can supply the needed power. You just don’t plug them into your typical headphone output. Needless to say, electrostatic headphones are not only more expensive than other types, but are also more expensive to operate.
Since introducing the SR-007 in 1998, STAX has been a leader in electrostatic headphones, delivering an immersive listening experience marked by increased detail, tonal accuracy, and comfort. With each new release, the SR-007 series continues STAX’s tradition in bringing the best technology and design for headphone listening. The addition of the SR-007S electrostatic earspeaker is the latest addition in the SR-007 Series.
Pro Tip: STAX refers to their Electrostatic Headphones as Earspeakers.
STAX SR-007S Technology Improvements
The SR-007S features updated diaphragms and fixed electrodes, building on the SR-007 and SR-007A designs. This elevates sound detail clarity while maintaining deep, resonant tones. The newly redesigned large circular fixed electrodes feature a 20% reduction in air vent hole diameter compared to earlier models. This high-precision etching process further optimizes the acoustic sound profile of the product.
ARS (Anti Resonance Structure) Improvements
The SR-007S incorporates a distinct arc inspired by the flagship SR-X9000, utilizing a seamless stainless steel plate for improved rigidity and vibration reduction. An innovative movable hinge section improves fit and comfort, while rubber material on the head pad attachment preserves the SR-007 series signature, adjustment-free, snug fit.
New Sheepskin Earpads
The SR-007S earpads feature a rotating design that easily adapts, resulting in improved comfort and fit. Crafted from premium sheepskin, the material bolsters sound quality by reducing unwanted reflections and optimizing acoustic absorption. The redesigned inner earpad further refines sound absorption. This provides a heightened sense of perspective and contributes to a more expansive, precise soundscape. Finished in a STAX signature brown, it pays homage to the traditional aesthetic of the 007 series.
Detachable Cable
A detachable cable system has been implemented for easy maintenance, longevity of the ear speaker as well as future support and replacement, when needed.
Comparison
| STAX Model | SR-007S (2025) | SR-X9000 (2021) | SR-007MK2/SR-007A (2007) |
| Product Type | Electrostatic Headphones | Electrostatic Headphones | Electrostatic Headphones |
| Price | $2,200 | $6,200 | $2,205 (Discontinued) |
| Headphone Type | Push-pull electrostatic open-air type headphone | Push-pull electrostatic sound element, open-air type headphone | Push-Pull electrostatic circular sound element, open-air type headphone |
| Sound element shape | Large round shape | Large round shape | Not indicated |
| Fixed Electrode | Yes | Yes – MLER-3 (Multi Layer Electrodes) | Yes |
| Frequency response | 6 – 41,000 Hz | 5 – 42,000Hz | 6 – 41,000Hz |
| Impedance | 145 kΩ | 145 kΩ | 170 kΩ at 10kHz |
| Capacitance | 94 pF (including cable) | 110 pF | 94 pF (including cable) |
| Sensitivity | 101 dB | 100 dB | 100 dB / 100V r.m.s. 1 kHz |
| Bias voltage | 580 V / DC | 580V DC | 580V DC |
| Ear pads | Genuine Lamb leather (skin touching portion), high-quality leather (surrounding portion). | Genuine Sheep Leather (direct skin contact), high-quality synthetic leather (surrounding portion) | Genuine Lamb Leather (direct skin contact), high-quality synthetic leather (surrounding portion) |
| Cable | 2.5m, parallel 6-strand, low capacitance cable | 2 Cables: 2.5m and 1.5m parallel 6-strand, low-capacity wide cables | 2.5m/8.2ft low capacity wide format, PC-OCC (Pure Crystal Ohno Continuous Casting) |
| Attached cable conductor | Not Indicated | 6N (99.9999%) OFC + silver plated annealed copper wire | Not Indicated |
| Weight | 430 g (15.2 oz) | 432 g (15.24 oz) | 365.7 g (12.9 oz) without cable 499 g (1.1 lbs) with cable |
Pro Tip: The SR-007MK2 is intended for sale internationally (including North America) and usually has a black finish. The SR-007A is the version intended for sale only in Japan and usually has a silver finish. Both have the same specs and are no longer available.
The Bottom Line
When it comes to headphones, “electrostats” are a different ball game. If you have ever heard an electrostatic speaker, such as those made by MartinLogan and Final-Audio, imagine that same type of performance on a much smaller scale via headphones.
STAX is the top dog in the electrostatic headphone category, and their new SR-007S continues the legacy of their 007 series and also borrows a little from their current flagship SR-X9000.
However, although STAX has a significant electrostatic headphone product line (aka ear speakers), there is competition from other companies such as Audeze, HiFiMAN, and Warwick Acoustics at higher price points.
With the cost of purchasing and operating electrostatic headphones, they are not for the casual listener; they are for the dedicated audiophile looking for the best headphone listening option possible. If you fall into that group, then the STAX SR-007S falls in the middle of the pack in terms of price. However, there is hope for more budget-minded headphone fans as STAX has also introduced the SR-X1 for the “low price” of $535!
Price & Availability
The STAX SR-007S Electrostatic Earspeaker will be available for order starting June 30th, 2025, for $2,200 at staxheadphones.com.
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