STAX
Japanese acoustic manufacturer founded in 1938. Nearly the world's only specialist in developing and manufacturing electrostatic headphones (which they call 'earspeakers'). Their unique method of driving ultra-thin diaphragms with high voltage achieves ultra-low distortion and high resolution difficult to attain with other methods. Since 2011, under the ownership of China's Edifier, they continue to preserve their unique technology with a stable management foundation. While handling requires a dedicated amplifier and isn't convenient, their unique sound continues to receive enthusiastic support from audiophiles worldwide.
Overview
Founded in 1938 by Naoshi Hayashi, STAX is a Japanese veteran manufacturer specializing in electrostatic headphones. The company refers to its products not as “headphones” but as “earspeakers,” emphasizing their speaker-like qualities worn on the ears. Since 2011, they have been under the ownership of Edifier, a major Chinese audio manufacturer, continuing their traditional technology development.
The core of their technology lies in the electrostatic drive method. An ultra-thin diaphragm measured in micrometers is placed between two fixed electrodes charged with high voltage, generating sound by vibrating according to the music signal. This method drives the entire diaphragm uniformly, theoretically eliminating split vibration and achieving extremely low distortion with delicate, high-resolution sound.
However, this method requires high voltage and cannot connect to standard headphone jacks, making a dedicated amplifier (which they call a “driver unit”) essential. Their unique technology and sound have been supported by dedicated audio enthusiasts for many years.
Scientific Validity
\[\Large \text{0.9}\]The scientific superiority of electrostatic drivers is clearly demonstrated by measurement data. The SR-009S (USD 4,000) performance of THD+N below 0.01% is overwhelmingly superior compared to other driver types in the same price range (typically 0.1-0.3%). The excellent transient characteristics due to extremely low diaphragm mass are also demonstrated in measurements such as square wave response. High driving force from high-voltage operation surpasses other methods in sound pressure level linearity. These physical advantages appear as identifiable differences in ABX tests.
Technology Level
\[\Large \text{1.0}\]As the world’s only company mass-producing electrostatic headphones, they maintain the highest level of technical capability. In particular, polymer film thinning technology, high-voltage safety technology, and long-term stability assurance technology reach levels difficult for other companies to achieve. The SR-009S uses an ultra-thin 1.35-micrometer diaphragm, and the technology to safely drive this with thousands of volts represents the crystallization of over 80 years of technical accumulation. System optimization is achieved through combination with dedicated amplifiers.
Cost-Performance
\[\Large \text{0.5}\]While electrostatic headphones are technically irreplaceable by other methods, pure measured performance versus price yields a harsh evaluation. A high-performance DAC + amplifier + headphone combination achieving THD+N below 0.01% equivalent to the SR-009S (USD 4,000) is possible for about USD 2,000 with Topping A90D (approximately USD 567) + HiFiMAN HE1000se (approximately USD 1,433), giving CP = USD 2,000 ÷ USD 4,000 = 0.5. For the SR-L700MK2 (approximately USD 1,133), the HiFiMAN Arya Organic (approximately USD 1,133) exists with equivalent measured performance and can be driven by normal headphone amplifiers without a dedicated amp, making the overall system significantly cheaper.
Reliability & Support
\[\Large \text{0.9}\]As a specialized manufacturer with over 80 years of history, they boast extremely high reliability. Electrostatic driver durability is particularly excellent, withstanding decades of use under proper management. The warranty period is 2 years with comprehensive repair services. However, due to high voltage use, a dedicated amplifier is required, and attention to humidity management is necessary. Long-term parts supply continues, enabling repair support for older models. Domestic manufacturing and support systems in Japan provide additional peace of mind.
Rationality of Design Philosophy
\[\Large \text{1.0}\]An extremely rational design philosophy maximizing the physical advantages of electrostatic drivers. Diaphragm weight reduction, distortion reduction through full-surface drive, and high damping factor from high-voltage drive are all optimizations based on physical laws. Enclosure design adopts an open-back structure leveraging electrostatic driver characteristics, which is acoustically sound. There are no unscientific elements, with abundant support from technical papers. The high price is reasonable considering technical complexity and manufacturing costs.
Advice
STAX products are choices for the highest-level audiophiles who refuse any compromise in sound quality. However, due to the special drive method, thorough consideration before purchase is necessary.
- Beginners: We recommend gaining experience with other driver types first. Electrostatic types require special management, and appreciating the sound differences requires appropriate experience.
- Intermediate and above: We recommend starting with SR-L300ES or SR-L700. After understanding electrostatic characteristics, consider advancing to higher models.
- Advanced users: SR-009S, SR-X9000, and SR-007 series suit those seeking the highest currently available sound quality.
Remember that a dedicated amplifier is required for purchase. Also, understand the special maintenance requirements including humidity management and static electricity countermeasures before adoption. While certainly expensive, the technical superiority of electrostatic technology and the resulting sound experience offer value absolutely irreplaceable by any other means.
(2025.7.5)