Overview

TimeDomain Corporation began as an audio lab within ASCII Research Institute in November 1996 and became independent in September 1997. It promotes a proprietary “time-domain theory” and sells amplified speaker systems such as the cylindrical Yoshii9 series [1][2].

Scientific Validity

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We find no credible third-party anechoic measurements (frequency response, THD, dynamic range, etc.). Manufacturer specs for Yoshii9 MK2 include an 8 cm full-range driver and a bundled amplifier rated at 12 W + 12 W with mini/RCA inputs—catalog values rather than independent tests [2]. While the firm emphasizes group-delay flatness in its theory documents, objective demonstrations of audible superiority are not provided [6].

Technology Level

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The system architecture—single full-range drivers in a resonance-controlled cylindrical enclosure with a dedicated amplifier—shows a consistent design intent. However, without CTA-2034-class third-party data or peer-reviewed validation, the achieved performance relative to modern studio monitors remains unclear [2][6].

Cost-Performance

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We use the currently available Yoshii9 MK2 (speaker + amplifier) as TimeDomain’s representative product. Its market price is about 2,230 USD (converted from 2200 USD at the official rate on 2025-08-19) [2]. As the cheapest equal-or-better comparator with published measurements, we select JBL 305P MkII (pair)—amplified, with balanced inputs and full CTA-2034 data [3]; Sweetwater pair price is 318 USD [4].

• Equivalence note (short): Amplified speakers with analog inputs; objective data (spinorama and specs) indicate at least comparable transparency on common metrics [3][4].

CP calculation (single representative product):
CP = Cheapest equivalent price ÷ Representative product price = 318 USD ÷ 2,230 USD = 0.14 → 0.1 (rounded, clamped at 1.0) [2][4].

Reliability & Support

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A domestic sales channel documents continuing repair availability, which supports long-term usability [5]. However, internationally published reliability statistics are scarce. We therefore assign a midpoint score.

Rationality of Design Philosophy

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Prioritizing time-domain behavior (e.g., group delay) is a reasonable focus, but the company has not disclosed how much improvement is achieved on measurable axes. With numerous monitors offering transparent, well-documented performance at far lower prices, price-to-rationality alignment is weak [3][6].

Advice

If you value measurement-backed transparency and value, start with active studio monitors that publish CTA-2034 data (e.g., JBL 305P MkII) [3][4]. If you are drawn to Yoshii9 MK2’s aesthetics or concept, proceed only after careful in-room audition and verifying return terms, acknowledging the absence of independent measurements. Should robust third-party data be released, reassessment would be warranted.

References

[1] “TIMEDOMAIN（タイムドメイン）の中古買取実績” (company outline): https://audio-kaitori.jp/maker/timedomain (accessed 2025-08-19)
[2] Meditations — “Yoshii9 MK2 (Speaker + Amplifier)” (price & specs): https://meditations.jp/products/yoshii9-mk2-speaker-amplifier (accessed 2025-08-19)
[3] Erin’s Audio Corner — “JBL 305P MkII Review” (CTA-2034 data): https://erinsaudiocorner.com/loudspeakers/jbl_305pmk2/ (accessed 2025-08-19)
[4] Sweetwater — “JBL 305P MkII 5-inch Powered Studio Monitor” (pricing/specs): https://www.sweetwater.com/store/detail/LSR305MK2–jbl-305p-mkii-5-inch-powered-studio-monitor (accessed 2025-08-19)
[5] TIMEDOMAIN Lab mini shop (repair note): https://www.timedomain.shop/items/4947337 (accessed 2025-08-19)
[6] TIMEDOMAIN document (group-delay emphasis PDF): http://www.timedomain.co.jp/documents/2003masscom/extend_td.pdf (accessed 2025-08-19)

(2025.8.21)