Overview

The 7Hz Timeless II is a second-generation planar magnetic in-ear monitor featuring an upgraded 14.5mm driver with the world’s first dual-sided silver alloy-coated diaphragm in an IEM platform. Priced at 229 USD, it includes a tunable nozzle system for sound customization and represents 7Hz’s continued exploration of planar magnetic technology in portable audio devices.

Scientific Validity

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The Timeless II demonstrates measurable technical performance improvements over its predecessor, with manufacturer specifications indicating THD <0.2% at 1kHz, which approaches excellent level (0.05%) for headphones according to transparent audio criteria [1]. Sensitivity increased from 104dB/V to 108dB/V compared to the original model, providing excellent efficiency for most source devices [2]. The frequency response extends from 5Hz-40kHz with the dual-sided silver alloy coating process designed to increase diaphragm surface tension. The 14.5mm planar driver with dual-sided N52 magnet array represents significant technical advancement in planar magnetic technology. Third-party frequency response measurements from IEC-711 clone microphone sources show controlled V-shaped tuning characteristics with good technical performance [2]. While comprehensive measurement data remains limited, the available specifications and third-party assessments indicate meaningful technical performance approaching transparent levels.

Technology Level

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The Timeless II demonstrates meaningful technological advancement through proprietary innovations. The dual-sided silver alloy coating process represents the first implementation in IEM platforms, featuring microns-thick even surface application that increases diaphragm surface tension. The 14.5mm planar driver with dual-sided N52 magnet array shows progression from the previous 14.2mm generation. The tunable nozzle system, inspired by speaker phase plugs, allows user frequency adjustment. These developments represent contemporary planar magnetic technology with some competitive advantage, though the fundamental planar IEM approach has become widely adopted across manufacturers.

Cost-Performance

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The Letshuoer S12 at 99 USD is equipped with equivalent-or-better planar magnetic technology using a larger 14.8mm planar driver, similar frequency response characteristics (20Hz-30kHz), and equivalent connectivity options with detachable cable system, providing superior core planar magnetic performance with larger driver technology [3]. The Truthear Zero Red at 55 USD provides equivalent frequency response characteristics and low distortion performance using dynamic driver technology, demonstrating superior cost-performance [4]. CP = 55 USD ÷ 229 USD = 0.2

Reliability & Support

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The Timeless II provides below-average warranty coverage with only 1 year manufacturer warranty, shorter than the typical 2-year industry standard. Cable warranty is limited to 3 months, indicating potential reliability concerns. Support infrastructure relies on standard dealer-based systems through Linsoul, with customer service available Monday-Saturday 10am-7pm with 2-3 hour response times. The simple planar magnetic construction with 7-layer acoustic enclosure suggests inherent reliability, but limited long-term track record and shorter warranty period reduce overall confidence in long-term support.

Rationality of Design Philosophy

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7Hz demonstrates exceptional scientific approach to driver development through measurable improvements in diaphragm coating technology and sensitivity enhancement from 104 to 108 dB/V compared to the original model. The dual-sided silver alloy coating process represents the first implementation in IEM platforms, featuring measurable improvements in diaphragm surface tension through proprietary coating technology. The tunable nozzle system provides user customization based on acoustic principles similar to speaker phase plugs, allowing frequency response adjustment. The evolutionary approach focuses on proven planar magnetic technology optimization with cutting-edge materials engineering. The development direction emphasizes measurable performance improvements through advanced coating technology and driver optimization, demonstrating highly rational engineering philosophy focused on technical advancement.

Advice

For users prioritizing cost-performance, consider the Truthear Zero Red at 55 USD which provides equivalent frequency response characteristics and low distortion performance using dynamic driver technology, offering equivalent-or-better performance at 174 USD less than the Timeless II. For those specifically seeking planar magnetic technology, the Letshuoer S12 at 99 USD provides superior value with its larger 14.8mm planar driver. The Timeless II’s tunable nozzle system and dual-sided silver alloy coating offer advanced customization features, but the 130 USD price difference is excessive relative to performance gains. The limited 1-year warranty suggests purchasing from retailers with extended protection plans. Users prioritizing cutting-edge planar technology should consider the Timeless II’s world-first dual-sided coating implementation, while those seeking proven performance may find excellent value in the S12 or Zero Red.

References

[1] Linsoul Audio, 7HZ Timeless II Product Page, https://www.linsoul.com/products/7hz-timeless-ii, accessed 2025-09-13 [2] Headfonics, 7Hz Timeless II Review with IEC-711 measurements, https://headfonics.com/7hz-timeless-ii-review/, 2024 [3] Letshuoer, S12 14.8mm Planar Magnetic IEM, https://letshuoer.net/products/s12-hifi-earphones-planar-iems, pricing 99 USD, accessed 2025-09-13 [4] Truthear, Zero Red Dynamic Driver IEM, https://truthear.com/products/zero-red, pricing 55 USD, accessed 2025-09-13 [5] Linsoul Audio, Return Policy & Warranty, https://www.linsoul.com/pages/return-policy-warranty-b, accessed 2025-09-13

(2025.9.13)