The S-Trax from Fyne Audio is a super tweeter fitted with a 25 mm magnesium dome and an omnidirectional dispersion design. It extends the hi-fi system’s frequency response up to 50 kHz. Designed to match Fyne Audio speakers, particularly the F500 series, it aims to improve spatial continuity and high-frequency reproduction. Its high-pass filter set at 16 kHz and level adjustment allow tuning according to the listening setup.
Design and physical architecture
The S-Trax stands out with its compact 79 x 82 x 149 mm enclosure weighing 1 kg. Its satin black finish blends discreetly into existing installations. The chassis houses a 25 mm magnesium dome driver, a material selected for its rigidity and lightness. The neodymium magnet generates a powerful magnetic field in a compact volume, enabling precise control of diaphragm movement.
The omnidirectional geometry of the S-Trax is its distinctive feature. Unlike conventional front-radiating tweeters, this design propagates high frequencies in all directions, creating a more uniform sound field in the listening room. This approach promotes spatial coherence and reduces timbre variations according to listening position. The tweeter can be positioned on top of a floorstanding speaker or near a bookshelf speaker system.
Signal processing and filtering
The integrated crossover circuit uses a third-order high-pass filter at 16 kHz. This high crossover frequency allows the S-Trax to handle only the extreme treble, leaving lower frequencies to the speaker’s main tweeters. The CryoLite treatment applied to the crossover components aims to improve electrical conductivity and reduce micro-distortion. This cryogenic process gradually cools electronic components to extreme temperatures, altering their crystalline structure.
A rotary potentiometer on the rear panel offers an adjustment range of ±4.5 dB around the nominal level. This flexibility makes it possible to adjust tonal balance according to personal preferences, room acoustics, or the characteristics of the main speakers. The nominal 8-ohm impedance ensures compatibility with most amplifiers, with maximum permissible power reaching 400 watts RMS.
Frequency range and sound reproduction
The S-Trax frequency response extends from 16 kHz to 50 kHz with a -6 dB cutoff point. This extension beyond the theoretical limit of human hearing (around 20 kHz) is the subject of debate within the audio community. Some listeners report improved transparency and spatialisation, potentially linked to harmonic interactions and reduced phase distortion in the upper audible spectrum.
The S-Trax sensitivity is suited to speakers reaching 98 dB, ensuring level balance with relatively efficient systems. Adding this super tweeter can alter the perception of cymbals, violin harmonics, and acoustic ambience. Fast transients particularly benefit from the lightness of the magnesium dome, which responds quickly to signal variations.
Integration into an audio system
The S-Trax connects in parallel with the main speakers via screw terminals located at the rear of the enclosure. Simple wiring requires no modification to the existing system. For Fyne Audio’s F500E, F500S, and F500SP series, the super tweeter naturally complements IsoFlare technology, forming continuity with the coaxial drivers in these models.
Physical placement significantly influences the sound result. Positioning it high up, above the main speakers, generally enhances the perception of height and openness in the soundstage. The omnidirectional nature of the S-Trax offers some tolerance for exact placement, although vertical alignment with the other drivers remains preferable to maintain time coherence.
Pairing it with speakers from other brands requires a phase of level potentiometer adjustment. It is advisable to begin with the setting at minimum, then gradually increase it while listening to material rich in high-frequency harmonics. Excessive level results in artificial brightness or listening fatigue, while insufficient level makes the super tweeter ineffective.
Technical specifications
Transducer and technology
Speaker type: 25 mm magnesium dome with neodymium magnet
Design: time-aligned omnidirectional design
Filtering: 3rd-order high-pass filter at 16 kHz with CryoLite treatment
Acoustic performance
Frequency response: 16 kHz to 50 kHz (-6 dB measurement, typical in-room)
Sensitivity: compatible with speakers up to 98 dB (2.83 V / 1 m)
Level adjustment: ± 4.5 dB from nominal setting
Electrical characteristics
Nominal impedance: 8 ohms
Recommended amplification power: up to 400 W RMS (maximum)
Dimensions and finish
Dimensions: 79 x 82 x 149 mm (height x width x depth)
Net weight: 1 kg
Available finish: satin black
Compatibility and integration
Optimal compatibility: F500E, F500S, F500SP series equipped with IsoFlare technology
Universal compatibility: easily integrates with most hi-fi speakers
Recommended use: high-end hi-fi systems and home theater
General information
The high-frequency super tweeter combines a time-aligned omnidirectional design with a 25 mm magnesium dome transducer featuring a neodymium magnet. This SuperTrax-derived technology delivers extreme extension of the sound spectrum up to 50 kHz for ultra-detailed reproduction of high frequencies.
The premium construction incorporates CryoLite filtering and allows a customizable adjustment of ± 4.5 dB to suit any system. The omnidirectional design ensures better dispersion and optimal spatial coherence.
Ideal for listeners seeking greater clarity, presence, and air in the treble, this super tweeter pairs perfectly with Fyne Audio F500 series speakers and guarantees exceptional tonal accuracy and naturalness.
Frequently Asked Questions
Can I use the S-Trax with any hi-fi speaker?
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The S-Trax works with most speakers with a sensitivity of up to 98 dB. The 16 kHz crossover ensures that it does not interfere with existing tweeters. However, the effect will be more noticeable with mid- to high-quality speakers, as entry-level systems may not necessarily reveal the nuances provided by the frequency extension.
How do I properly adjust the super tweeter level?
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Start with the potentiometer at minimum. Listen to a familiar track rich in cymbals or high-frequency instruments. Gradually increase the level until you notice improved definition without excessive treble. If vocals become sibilant or cymbals too prominent, reduce it slightly. The optimal setting depends on your system and preferences.
Does CryoLite treatment make an audible difference?
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Cryogenic treatment of the filter components aims to reduce micro-distortions and improve conductivity. The effect remains subtle and difficult to isolate from the S-Trax’s other characteristics. This technique is part of an overall approach to manufacturing quality rather than a radical modification of the sound.
Do two S-Trax need to be used for a stereo setup?
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Yes, to maintain the symmetry and coherence of the stereo image, one super-tweeter per channel is required. Using a single S-Trax would create a tonal imbalance between the left and right channels, impairing the precise localization of sound sources.
What is the difference between S-Trax and ribbon tweeters?
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The S-Trax uses a magnesium dome, whereas ribbon tweeters employ a thin conductive diaphragm. Ribbons generally offer a larger radiating surface and limited vertical dispersion, while the S-Trax dome radiates omnidirectionally. Both technologies aim for extended frequency response, but with distinct sound signatures.
Does the S-Trax require a power supply?
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No, the S-Trax is a passive transducer powered directly by the amplifier via the speaker terminals. No mains power supply is required, simplifying installation and avoiding electrical noise issues.
User reviews
Cyril
So what can I say, paired with a set of Fyne Audio F502 SP: more fluid soundstage, better definition from bass to treble, more natural sound, more detail. I have absolutely no regrets about my purchase and I recommend it to anyone who owns Fyne Audio speakers.
Comment from November 29, 2025 — Experience from November 17, 2025
Automatically translated — Show original (French)
Alors que dire voilà, associé a une paire de fyne audio F502 SP
Scène sonore plus fluide , plus de définition du grave a l aigu,son plus naturel, plus de détails aucun regret de mon achat je le recommande pour se qui possède des fyne audio
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