Overview

The TEAC HP-F200 (branded “FillTune HP-F200”) is a bone conduction stereo headphone system released in March 2008 and currently discontinued. It is a two-component system: a bone conduction headphone unit using a supermagnetostrictive transducer co-developed with Frey Corporation, and a dedicated portable beltpack amplifier with a built-in lithium polymer battery. Audio is transmitted through skull and cheekbone vibrations directly to the cochlea, bypassing the eardrum and allowing ambient sound awareness during use. The product was distributed in the US under both TEAC and TASCAM FillTune branding at approximately USD 499. TEAC handled manufacturing and after-sales support; the FillTune trademark belongs to Frei/Frey Corporation.

Scientific Validity

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The HP-F200’s beltpack amplifier carries a manufacturer-published electrical frequency response of 25Hz–20kHz (+0/−3dB) [1][2]. This specification describes the amplifier’s electrical signal path only — it is not a measurement of the acoustic output delivered to the cochlea via bone conduction. Bone conduction physics impose severe attenuation below approximately 600Hz regardless of amplifier electrical performance, and this constraint applies universally to consumer bone conduction devices using skin-contact transducers. No manufacturer-published acoustic performance specifications for THD, S/N ratio, sensitivity, or crosstalk are available. No credible third-party acoustic measurements exist for this product, consistent with the absence of standardized consumer bone conduction measurement infrastructure across the industry.

The one quantifiable characteristic is passive sound isolation: as an open-ear design where transducers rest on the cheekbones without any ear coverage, isolation is approximately 0dB. This provides essentially no passive sound isolation — a universal characteristic of open-wear bone conduction headphones rather than a product-specific deficiency. With this one confirmed unfavorable metric and acoustic performance data unavailable for all remaining criteria, the score is set to 0.5.

Technology Level

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The HP-F200 employed a supermagnetostrictive transducer co-developed with Frey Corporation, using rare-earth alloy materials in the Terfenol-D class [1][3]. Magnetostriction — the dimensional change of ferromagnetic materials under a magnetic field — enables high-speed mechanical vibration and theoretically extends high-frequency bone conduction output beyond electromagnetic or piezoelectric alternatives. The transducer was designed for application to the zygomatic process with a contact area of approximately 4.15 cm², and the beltpack amplifier was an in-house TEAC design providing 2.8W per channel output. These represent genuine technical effort for the 2008 timeframe.

Evaluated against the 2026 state of the art as required, the picture is unfavorable across nearly every dimension. The product was discontinued approximately 15 years ago. No TEAC-owned patents were identified for this core transducer technology. The magnetostrictive approach was not adopted by any other consumer bone conduction manufacturer — the entire category subsequently converged on electromagnetic transducer designs (Shokz, etc.) that are lighter, cheaper, and adequate in performance. The system is entirely analog and mechanical with no DSP processing, no wireless connectivity, and no software integration of any kind. A technology that no competitor adopted offers no lasting competitive advantage, and the industry’s collective rejection of the magnetostrictive path for consumer bone conduction is now definitive.

Cost-Performance

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This site evaluates based solely on functionality and measured performance values, without considering driver types or configurations.

The HP-F200’s historical US retail price was approximately USD 499 [1][3]. No current market price exists as the product is discontinued; used and secondary market prices are not considered in this evaluation.

HP-F200 user-facing functions and specifications:

• Bone conduction audio delivery (skull/cheekbone vibration, bypassing the eardrum)
• Open-ear ambient sound awareness (~0dB passive isolation by design)
• Portable battery operation: ~8 hours (lithium polymer, manufacturer spec)
• Wired connectivity: 3.5mm LINE/MIC input to beltpack amplifier
• Electrical frequency response: 25Hz–20kHz (+0/−3dB) (manufacturer spec, amplifier electrical path)
• Volume and left/right balance controls (beltpack dials)

The Shokz OpenRun (USD 129.95 regular price at Shokz.com) [4] provides equivalent or better performance across all essential user-facing functions [5]:

Metric	TEAC HP-F200	Shokz OpenRun	Status
Bone conduction audio	Yes — skull/cheekbone vibration, bypassing eardrum	Yes — skull/cheekbone vibration, bypassing eardrum	Equivalent
Passive sound isolation	~0dB (open-ear, no ear coverage)	~0dB (open-ear, no ear coverage)	Equivalent
Battery life	~8 hours (manufacturer spec)	8 hours (manufacturer spec, confirmed [5])	Equivalent
Electrical FR	25Hz–20kHz ±3dB (manufacturer spec)	20Hz–20kHz (manufacturer claim)	Provisionally equivalent-or-better
Connectivity	Wired 3.5mm LINE	Bluetooth 5.1	Equivalent for modern sources

No standard acoustic measurement infrastructure exists for bone conduction headphones at mainstream consumer measurement platforms; this comparison is provisional and based on manufacturer specifications and qualitative third-party assessments.

CP = 129.95 USD ÷ 499 USD = 0.2605 → 0.3

Reliability & Support

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TEAC’s standard warranty period is 1 year — below the 2-year industry average — and coverage was restricted to the country of original purchase with no international transferability. The HP-F200’s design is inherently susceptible to degradation: an integrated lithium polymer battery loses capacity over charge cycles, and the specialized magnetostrictive transducers have no known current-market replacement or repair supply chain.

The product was discontinued approximately 15 years ago. TEAC’s stated 5-year parts retention window following production discontinuation has long since expired, and the HP-F200 does not appear on TEAC’s discontinued products support page — indicating no ongoing structured support pathway. No documented systematic failures or recalls were identified in available sources; discontinued status, expired parts support, shorter-than-average warranty, and aging-prone components nonetheless leave little practical basis to expect dependable long-term service.

Rationality of Design Philosophy

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The HP-F200 addresses a legitimate use case — audio playback for users with outer-ear hearing conditions and listeners requiring ambient sound awareness — and the product line showed genuine generational improvement from the HP-F100 predecessor: amplifier output increased 3.6×, system weight reduced 10–30%, battery changed from AA alkaline to lithium polymer, and price dropped from approximately USD 650 to USD 499 [3].

At its March 2008 introduction, bone conduction headsets targeted consumers were still a thin market. Comparable accessories commonly used wired analog connections to portable players and phones; Bluetooth-first implementations in bone conduction wearables scaled up only in later headset generations. Manufacturer documentation highlighted a cheek-contact magnetostrictive transducer aimed at usable high-frequency bone conduction behavior and cited concrete electrical amplifier specifications rather than narration-only tonal claims [1][2].

The launch-time trade-off buyers could verify in print was weighted toward electrical beltpack specs and ergonomics versus bone-to-cochlea acoustic metrics: flagship-tier retail pricing accompanied limited publicly stated head-transfer quantities (harmonic distortion, sensitivity, etc. tied to skull transmission), so comparing price to independently specified headphone acoustic performance was inherently difficult beyond the amplifier’s electrical-frequency claims.

Advice

The TEAC HP-F200 is a discontinued product and cannot be purchased new. Users seeking a bone conduction headphone for ambient-awareness listening or to accommodate outer-ear hearing conditions should consider current-generation alternatives. The Shokz OpenRun at USD 129.95 delivers equivalent bone conduction functionality in a 26g self-contained unit with Bluetooth 5.1, IP67 waterproofing, and active manufacturer support — at less than one-third the HP-F200’s original price. The magnetostrictive transducer approach used in the HP-F200, while technically substantive, did not translate into a durable performance or commercial advantage over electromagnetic designs that followed. For existing HP-F200 owners, no parts, repair, or manufacturer support can be expected given the elapsed support window; secondary market parts availability for the specialized transducer components is effectively nil.

References

[1] TEAC Corporation — HP-F200 Official Product Page (Feature) — https://teac.jp/jp/product/hp-f200-te/feature — Accessed 2026-04-30 (confirms discontinued status; primary product reference)

[2] TEAC Corporation — HP-F200 User Manual PDF (D01033400A) — https://teac.jp/downloads/teac/843/hp-f200_om_j.pdf — Accessed 2026-04-30 (primary source for amplifier specifications including electrical frequency response)

[3] AV Watch Impress — ティアック、性能向上を図った骨伝導ヘッドホン”Filltune”の後継 [JA] — https://av.watch.impress.co.jp/docs/20080311/teac.htm — Accessed 2026-04-30 (launch specifications; HP-F100 to HP-F200 improvements; US pricing reference)

[4] Shokz — OpenRun Product Page — https://shokz.com/products/openrun — Accessed 2026-04-30 (comparison target; regular price USD 129.95)

[5] SoundGuys — Shokz OpenRun Review — https://www.soundguys.com/shokz-openrun-review-71111/ — Accessed 2026-04-30 (confirms 8-hour battery life; documents bone conduction measurement infrastructure limitation with standard rigs)

(2026.5.6)