Overview

Lizer Lab JIJUMA-HORN is a fourth-generation ear tip in the JIJU family that uses a horn-shaped metal phase plug and semi-open side vents to alter the sound field at the ear. The project launched on Makuake on March 26, 2025, and retail kits are now sold via Amazon Japan in stainless-steel (SUS) and brass versions with multiple size/plug configurations. [1][4][8][9]

Scientific Validity

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Baseline is 0.5 when key measurements are unknown; we adjust down to 0.3 because no third-party data demonstrates objective improvements to audibility-relevant metrics (frequency response linearity, distortion, or passive isolation). The manufacturer positions JIJUMA-HORN as a semi-open tip with “good venting,” which generally trades isolation for openness—at odds with transparent-level isolation targets for IEMs. No blind-test or standardized coupler data substantiating the claimed “concert-hall-like” effect is available. [1]

Technology Level

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The horn-shaped phase-plug structure and vent strategy are original for ear tips and are supported by IP: JP 6621166 (stated by the manufacturer for the JIJU series) and US 11,240,581 “Earpiece and earphone using the same.” The engineering concept is clearly differentiated from conventional silicone tips, though industry adoption remains niche. [2][3]

Cost-Performance

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Review target price (denominator): JIJUMA-HORN M/M set with two plugs at 41 USD (Amazon Japan market price 5,960円 converted). Comparator (cheapest equivalent-or-better): SpinFit CP100 at 10.99 USD for two pairs; widely used, medical-grade silicone with patented swivel, and known to achieve consistent seal and isolation across many IEMs (used as a default tip in some B&K 5128 databases). Calculation: 10.99 USD ÷ 41 USD = 0.27 → 0.3. [4][5][6][7][8]

Why CP100 qualifies: it reliably provides equal or better user-facing functions (fit/seal, comfort, durable silicone) and no evidence shows JIJUMA-HORN exceeding CP100 on measured transparency (FR/THD/Isolation). Therefore CP = 0.3.

Reliability & Support

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Lizer Lab is a small Japanese maker that originally crowdfunded JIJUMA-HORN, and the line has since moved to Amazon Japan. That improves availability but global support remains limited; long-term durability data for the complex horn insert is absent. Risk profile is average for a boutique accessory. [1][4][8][9]

Rationality of Design Philosophy

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Directing part of the acoustic energy via a horn-like plug toward the tragus and adding side vents is a plausible approach to alter cues, but claims about concert-hall spatiality remain uncorroborated by controlled measurements. The design is interesting and internally consistent, yet it prioritizes a novel presentation over measurable transparency. [1][2][3]

Advice

If you specifically want to experiment with front-localized, semi-open presentation and accept unverified claims, JIJUMA-HORN is a unique option. For most listeners seeking reliable seal, comfort, and stable tonality at low cost, SpinFit CP100 (or similar mainstream tips) delivers better value and predictability.

References

[1] Makuake project page, “音が見える。日米特許技術でホールの臨場感…（JIJUMA-HORN）,” Mar 26, 2025, accessed 2025-08-19. https://www.makuake.com/project/jijuma-horn/
[2] Lizer Lab (official), “JIJU-JETの特徴” — note of JP Patent No. 6621166, accessed 2025-08-19. https://lizerlab.com/page/JIJU-JET_feature
[3] Journal of the Acoustical Society of America, “Reviews of Acoustical Patents — 11,240,581: Earpiece and earphone using the same,” Jul 1, 2022, accessed 2025-08-19. https://pubs.aip.org/asa/jasa/article/152/1/1/2838296/REVIEWS-OF-ACOUSTICAL-PATENTS
[4] Amazon.co.jp, “LIZER LAB イヤーピース JIJUMA-HORN (M/Mサイズ),” price observed 5,960円, accessed 2025-08-19. https://www.amazon.co.jp/dp/B0FL15SHHW
[5] Audio46, “SpinFit CP100 Silicon Eartips (2 Pairs),” price 10.99 USD, accessed 2025-08-19. https://audio46.com/products/spinfit-cp100-silicon-eartips
[6] SpinFit (official), product overview and specs, accessed 2025-08-19. https://spinfit-eartip.com/
[7] HypetheSonics HATS Database — measurement notes (B&K 5128; default tips include SpinFit CP100/CP800), accessed 2025-08-19. https://www.hypethesonics.com/hatsdbc_about/
[8] @Press release, “音が見える。日米特許技術で革新的イヤーピース 第4弾…,” Apr 21, 2025 — price bands incl. 5,960円 for 2-plug sets, accessed 2025-08-19. https://www.atpress.ne.jp/news/432417
[9] Lizer Lab blog, “マクアケ第四弾『JIJUMA-HORN』2025年3月26日公開予定！,” link to project page; accessed 2025-08-19. https://lizerlab.com/blog/details/makuake_jijuma_horn

(2025.8.19)