Overview

The STAX SR-X1 is an entry-level electrostatic earspeaker that revives the classic circular form with modernized mechanics and cabling. It targets first-time electrostatic buyers and is listed at 535 USD on the official store [1]. In Japan, the MSRP is 66,000円 [3]. A bundle with the SRM-270S energizer (SRS-X1000) is also available [4].

Scientific Validity

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Independent third-party measurements (FR deviation, THD vs SPL, unit variance) are not yet widely published. Manufacturer specifications list 7–41,000 Hz reproduction band, sensitivity 101 dB/100 V rms at 1 kHz, impedance 145 kΩ at 10 kHz (including 2.5 m cable), weight 234 g, and DC 580 V bias [1][3]. Pending lab-grade data (or controlled ABX), the score remains at the 0.5 baseline.

Technology Level

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SR-X1 employs a push-pull electrostatic circular driver with etched electrodes, an open-back slit structure to smooth airflow, a more rigid metal arc assembly, and a low-capacitance OFC “wide” cable [1][3]. These are sensible refinements for an entry model, yet evolutionary rather than category-advancing; hence 0.6.

Cost-Performance

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Comparator (cross-category, chosen by function & published specs): Sennheiser HD 560S — open-back, wired over-ear headphone with published THD < 0.05% (1 kHz / 90 dB) and FR 6 Hz – 38 kHz; both are at least on-paper equal or superior along audibility-relevant axes vs the SR-X1 whose THD is not published [5][6]. Current new price 199.95 USD (official US store) [5].

Calculation (explicit): 199.95 USD ÷ 535 USD = 0.3737… → 0.4 (rounded to one decimal).
Note: Within electrostatics specifically, SR-X1 remains the lowest-priced new over-ear option; however CP is evaluated across categories and strictly by user-visible function and published performance.

Reliability & Support

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Electrostatic drivers are mechanically simple (few moving parts). STAX has long product continuity (+0.1). Warranty is standard (JP: 1 year) [3]. Support is dealer-centric (±0). The official SR-X1 + SRM-270S bundle indicates parts/system continuity [4]. Net 0.7.

Rationality of Design Philosophy

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Requiring a dedicated energizer and bias voltage limits amplifier flexibility and portability. Without verified transparency-level measurements yet, the approach trades convenience for a specific transducer principle; rational for niche use, but not broadly optimal per dollar → 0.3.

Advice

SR-X1 suits listeners intentionally entering the STAX ecosystem at the lowest new-market price for an over-ear electrostatic. Budget for a compatible energizer and evaluate fit/comfort. If your priority is neutral tuning with strong published/third-party metrics at lower system cost, well-measured open-backs like the HD 560S merit consideration [5][6].

References

[1] STAX Headphones (Global Shop). “SR-X1 Electrostatic Earspeaker” — specs & listing. https://staxheadphones.com/products/sr-x1-earspeaker (accessed 2025-08-28).
[2] STAX (JP). “SR-X1” — official JP page, MSRP 66,000円. https://stax.co.jp/product/sr-x1/ (accessed 2025-08-28).
[3] STAX (JP). “SRS-X1000” — SR-X1 + SRM-270S official bundle. https://stax.co.jp/product/srs-x1000/ (accessed 2025-08-28).
[4] Sennheiser (US). “HD 560S” — official US page, price. https://www.sennheiser-hearing.com/en-US/p/hd-560s/ (accessed 2025-08-29).
[5] Sennheiser (EU). “HD 560S” — specifications incl. THD < 0.05% (1 kHz / 90 dB). https://eu.sennheiser-hearing.com/products/hd-560s (accessed 2025-08-29).
[6] Sennheiser Newsroom. “Reveal the truth in your music” (HD 560S launch; FR & THD). https://newsroom.sennheiser.com/reveal-the-truth-in-your-music (accessed 2025-08-29).

(2025.8.29)