Overview

The Kinera Celest Plutus Beast is a three-driver tribrid IEM that combines a customized bone-conduction unit, a balanced armature, and Kinera’s second-gen SPD (square planar) driver. Official specs list 8 Ω impedance, 108 dB sensitivity, and a 20 Hz–20 kHz response, packaged with a 5N silver-plated copper cable and 2-pin connectors [1]. Street price in the U.S. sits at 89 USD from authorized retailers [2]. While the configuration is ambitious for the sub-100 USD bracket, real-world behavior exposes design weaknesses that affect basic usability.

Scientific Validity

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Independent reviews consistently report a ringing/resonance that is triggered by minor bumps and even the wearer’s own voice (male speech especially), attributed to the contact-type bone-conduction driver coupling into the shell/ear [3]. Similar sensitivity to physical vibration (e.g., coughing, handling) is reported elsewhere [4]. Manufacturer specs (8 Ω, 108 dB; 20 Hz–20 kHz) are ordinary and provide no tolerance band for frequency-response deviation [1]. Reference Audio Analyzer lists the Plutus Beast as tested on an IEC-711 coupler (report dated 2025-03-27), indicating third-party measurement exists even though detailed public plots are limited [5]. As of August 19, 2025 we found no credible third-party THD/IMD or isolation numbers for this model. Given the documented resonance artifact—an audible defect in normal use—the scientific validity score is penalized.

Technology Level

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At this price, a 1 BC + 1 BA + 1 SPD tribrid with a custom 10 mm contact-type bone-conduction driver is technically adventurous, and the accessory/cable package is above average for the segment [1]. However, the execution appears insufficiently isolated/damped around the BC element, allowing mechanical excitation to leak into audible ringing in everyday scenarios [3][4].

Cost-Performance

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Target price: 89 USD [2].
Cheapest equivalent-or-better alternative (user-visible functions & measured performance): Truthear x Crinacle Zero: BLUE2 at 64.99 USD from a major retailer [6]. BLUE2 is a wired IEM offering the same core function (music playback via passive in-ear transducers) with frequency response that tracks modern targets closely on a B&K 5128 rig (public database) [7], and it does not exhibit the Plutus Beast’s BC-induced resonance problem reported by multiple reviews [3][4].

Computed CP (per site rules) rounds to 0.7.

Reliability & Support

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Kinera states a 1-year warranty for IEMs and standard return terms via its official site [1]. Construction (3D-printed resin shells, 0.78 mm 2-pin) is typical for the class [1]. Lack of long-term failure-rate data and the BC driver’s noted mechanical sensitivity temper the score [3][4].

Rationality of Design Philosophy

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Integrating bone conduction at low cost is noteworthy, but the implementation appears to undervalue isolation/damping essentials for contact-type transducers. The recurring resonance behavior under normal use suggests design priorities favored novelty over robust acoustical control, reducing the rationality of the approach [3][4].

Advice

For a reliable sub-100 USD pick with objectively safer tuning, choose Truthear x Crinacle Zero: BLUE2 (64.99 USD)—it aligns well to target FR on a 5128 rig and avoids the Plutus Beast’s resonance liability [6][7][3]. If you specifically want a Kinera/Celest style build and accessories, confirm your own-voice/handling tolerance in person before purchase; the resonance reports are not unit-isolated [3][4].

References

[1] Kinera, “Celest Plutus Beast — specs, cable & warranty,” kineraaudio.com, accessed 2025-08-19.
https://kineraaudio.com/products/celest%E5%A4%A9%E7%A6%84%E5%85%BDplutus-beast

[2] Bloom Audio, “Kinera Celest Plutus Beast | Tribrid BC + BA + Planar IEM,” price 89 USD, accessed 2025-08-19.
https://bloomaudio.com/products/kinera-celest-plutus-beast

[3] Prime Audio Reviews, “Kinera Celest Plutus Beast Review,” 2024-03-15, accessed 2025-08-19.
https://primeaudio.org/kinera-celest-plutus-beast-review/

[4] Mobileaudiophile, “Celest Plutus Beast Review: The Funny Beast,” 2024-02-06, accessed 2025-08-19.
https://mobileaudiophile.com/in-ear-earphones-iem-iems-reviews/celest-plutus-beast-review-the-funny-beast/

[5] Reference Audio Analyzer, “Target Harman In-Ear (2017) — device listings (includes ‘Kinera Plutus Beast’, tested on IEC-711; 2025-03-27),” accessed 2025-08-19.
https://reference-audio-analyzer.pro/en/report-pro-hp-target.php?id=4864

[6] ShenzhenAudio, “TRUTHEAR x Crinacle Zero: BLUE2,” price 64.99 USD (regular), accessed 2025-08-19.
https://shenzhenaudio.com/collections/truthear

[7] Crinacle, “5128 IEM Graphs — Zero:BLUE2 share view,” accessed 2025-08-19.
https://graph.hangout.audio/iem/5128/?share=ZS10Pro%2CZeroBLUE2%28Foam_tips%29

(2025.8.19)