Overview

The JBL Studio 680 is a 2.5-way floor-standing loudspeaker with dual 6.5-inch PolyPlas woofers and a 1-inch 2414H-1 compression driver loaded by an HDI (High Definition Imaging) waveguide. Manufacturer specifications list 38 Hz–40 kHz frequency response (±3 dB), 88 dB sensitivity (2.83 V/1 m), 6 Ω nominal impedance, dimensions 1005 × 230 × 300 mm, and per-unit mass ≈22.6 kg [1].
US street price (pair): 1,319.90 USD (derived as 659.95 USD each ×2) [2][7].

Scientific Validity

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Public third-party Klippel NFS/CTA-2034 measurements for Studio 680 could not be found at major measurement-first outlets as of this writing; therefore performance assessment relies on clearly labeled manufacturer specifications: 38 Hz–40 kHz (±3 dB), 88 dB (2.83 V/1 m), 6 Ω, and HDI waveguide/compression-driver topology [1]. Until independent data (on-/off-axis response, early reflections, PIR, nonlinear distortion) is published, this is a provisional score based on catalog specs.

Technology Level

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JBL’s HDI waveguide with a compression driver is a proven approach to controlling directivity and maximizing listening-window uniformity, and the 2.5-way network reflects competent engineering for this class [1]. Materials and topology are solid but not bleeding-edge; no onboard DSP/correction or novel transducer tech is present. Overall, a capable contemporary implementation rather than a technology leader.

Cost-Performance

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Studio 680 pair price (US): 1,319.90 USD (659.95 USD each ×2) [2][7].
The cheapest clearly equal-or-better alternative we identified is Monoprice Monolith THX-365T (passive mini-tower with Atmos module). It has strong independent measurements (Spinorama flatness ≈ ±1.8 dB; bass extension ~74 Hz) from NFS data [3][5] and THX Ultra certification [6]. THX-365T pair price (US): 799.98 USD (399.99 USD each ×2) [4].
Cost-performance ratio (cheapest equal-or-better ÷ target):

799.98 ÷ 1319.90 = 0.606 → 0.6 (rounded to one decimal).

Equivalence note: Both are passive floor-standing speakers; the 365T adds an Atmos top module and demonstrates equal-or-better measured linearity/directivity on third-party rigs [3][5].

Reliability & Support

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Typical 2-year warranty and global Harman service coverage; passive construction minimizes electronic failure points. PolyPlas cones and rubber surrounds are durable; compression drivers are robust in pro applications. No extended-warranty program is standard; overall reliability provisioning is above average but not class-leading.

Rationality of Design Philosophy

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The design pursues controlled directivity and adequate sensitivity with conventional passive networks and materials. This aligns with high-fidelity goals, but omits newer approaches (e.g., built-in DSP/room correction) that can further push audible transparency; thus the philosophy is reasonable yet conservative.

Advice

If you specifically want JBL’s HDI voicing and compression-driver dynamics in a compact tower, the Studio 680 is coherent. Objectively, though, measured-data leaders like Monolith THX-365T deliver comparable or better linearity/directivity for substantially less money [3][4][5][6]. For maximum value, prioritize models with published CTA-2034 (Spinorama) and low distortion; if Studio 680 measurements appear and confirm transparency, its scientific validity score should be revisited.

References

[1] JBL — STUDIO 680 Spec Sheet (PDF), dims/specs (accessed 2025-08-31): https://jp.jbl.com/on/demandware.static/-/Sites-masterCatalog_Harman/default/dw166bb235/pdfs/JBL_Studio6_680_Spec_Sheet_English.pdf
[2] Sky by Gramophone — JBL Studio 680 (Each) price 659.95 USD (accessed 2025-08-31): https://skybygramophone.com/products/jbl-studio-680-dual-6-5-inch-2-5-way-floorstanding-loudspeaker-each
[3] Erin’s Audio Corner — Monoprice Monolith THX-365T measurements (CTA-2034, Klippel NFS) (accessed 2025-08-31): https://erinsaudiocorner.com/loudspeakers/monoprice_monolith_thx_365t/
[4] Amazon (US) — Monoprice Monolith THX-365T, 399.99 USD (Each) (accessed 2025-08-31): https://www.amazon.com/Monolith-THX-365T-Certified-Enabled-Mini-Tower/dp/B07QS67HL5
[5] Spinorama.org — Monolith THX-365T overview (flatness ±1.8 dB, F3 ≈ 74 Hz) (accessed 2025-08-31): https://www.spinorama.org/?page=17&quality=high
[6] Monoprice — Monolith THX-365T product page (THX Ultra certification, topology) (accessed 2025-08-31): https://www.monoprice.com/product?p_id=34188
[7] Best Buy — JBL Studio 680 listing (Each) price 659.95 USD (accessed 2025-08-31): https://www.bestbuy.com/product/jbl-studio-680-dual-6-5-2-5-way-compression-driver-floorstanding-loud-speaker-each-dark-wood/J7LXFWXCWY

(2025.8.31)