Overview

The JBL K2 S9500 was a 1990s Project K2 flagship. It uses a four-module tower (base B95, LF modules 2000M/3000M, MF/HF module 4500M) arranged vertically to approximate a coaxial acoustic center. Manufacturer engineering documentation lists 97 dB sensitivity (2.83 V/1 m), 3 Ω nominal impedance (2.7 Ω min), and a −6 dB half-space bandwidth of 35 Hz–21 kHz; archival spec pages list a hefty 149 kg weight, reflecting its pro-influenced, horn-loaded design ethos [1][2].

Scientific Validity

\[\Large \text{0.6}\]

Independent, modern full-spin measurements are not available. Using manufacturer engineering data: frequency response 35 Hz–21 kHz (−6 dB, half space), sensitivity 97 dB (2.83 V/1 m), nominal impedance 3 Ω, minimum 2.7 Ω [1]. Horn loading and the virtual-coaxial geometry are acoustically rational. However, the lack of third-party measurements (e.g., full spin, distortion, directivity) keeps confidence moderate, and the low impedance may challenge some amplifiers [1][2].

Technology Level

\[\Large \text{0.7}\]

For its era the S9500 applied advanced mechanics (pin-disk centering, modular construction) and materials (Aquaplas-treated 1400Nd woofers, titanium-diaphragm 475Nd compression driver). Relative to current flagships, it predates modern simulation-driven waveguides, comprehensive spin-based voicing, and contemporary crossover optimization, so the technical approach feels dated even if still impressive [1][2].

Cost-Performance

\[\Large \text{0.1}\]

Comparator (cheapest equal-or-better today): Klipsch R-800F. Passive floorstander; frequency response 34 Hz–21 kHz (±3 dB) and sensitivity 98 dB (in-room) meet or exceed the S9500’s 35 Hz–21 kHz (−6 dB, half-space) and 97 dB on headline axes (conditions differ; manufacturer specs for both) [1][3].
Observed price 624.99 USD each → 1,249.98 USD/pair (authorized retailer) [4].
CP calculation: 1,249.98 USD ÷ 14,000 USD = 0.089 → score 0.1.

Equivalence note (user-visible axes): both are passive floorstanders; bandwidth and sensitivity are equivalent-or-better per manufacturer specs. This comparison is provisional due to the S9500’s limited third-party measurements. [1][3]

Reliability & Support

\[\Large \text{0.3}\]

This is a discontinued, ~35-year-old design with no factory warranty or parts pipeline. The multi-module mechanics add service complexity. While build quality was substantial, age-related issues (crossover capacitors, foams, adhesives) and the 3 Ω load reduce practical support prospects [1][2].

Rationality of Design Philosophy

\[\Large \text{0.6}\]

Efficiency, headroom, and pattern control via horn loading are rational choices for high-output listening. The virtual-coaxial vertical symmetry also targets imaging consistency. That said, the mass/complexity emphasis reflects 1990s priorities more than today’s measurement-centric optimization, where simpler enclosures often achieve comparable linearity with modern tools [1][2].

Advice

Collectors who specifically want 1990s JBL horn dynamics and the historical K2 lineage will value the S9500. If you prioritize verifiable neutrality per contemporary measurements and manufacturer support at a far lower outlay, current models like Klipsch’s R-800F provide clearer, warrantied value. For any S9500 purchase, inspect driver condition, crossover health, and all module interfaces.

References

[1] JBL, “K2-S9500 – Engineering Design Specification (1990),” https://www.cieri.net/Documenti/JBL/Documenti%20tecnici/JBL%20-%20K2-S9500%20-%20Engineering%20Design%20Specification.pdf, accessed 2025-08-24.
[2] オーディオの足跡, “JBL Project K2 S9500 の仕様,” https://audio-heritage.jp/JBL/speaker/s9500.html, accessed 2025-08-24.
[3] Klipsch, “R-800F Specification Sheet,” https://d2um2qdswy1tb0.cloudfront.net/spec-sheets/Reference-R-800F-Spec-Sheet.pdf, accessed 2025-08-24.
[4] Best Buy, “Klipsch Reference 800 Series Dual 8” Floor Standing Speaker (Each),” https://www.bestbuy.com/site/klipsch-reference-800-series-dual-8-600-watt-passive-2-way-floor-standing-speaker-each-black/6501480.p, accessed 2025-08-24.

(2025.8.24)