JBL Project K2 S5500 (1993)
The JBL Project K2 S5500 is a floor-standing, tall-boy speaker system. JBL released it in Japan in 1993 at ¥800,000 per unit (a later note lists ¥780,000 around 1994). It was developed with the sound quality concept and technology that produced the flagship S9500. It was a serious, high-end model, not a mass-market one.
Electrically, the S5500 is a 2-way, 3-speaker bass reflex design. Two 30 cm cone woofers (LE125S) handle the low band. A horn-loaded compression driver covers the highs: the 275 nd, a scaled-down version of the 475 nd. The 275 nd uses a 2-inch pure titanium diaphragm coated with JBL's Aqua Plus treatment. The biradial horn is made from a material JBL called COMPII - a polyester-based composite originally developed for space and military use, with roughly 2.5 times the density of MDF. The crossover is set at 800 Hz with an 18 dB/octave slope. The system also has a charge-coupled linear definition network: paired capacitors with a built-in battery applying bias voltage to suppress zero-cross distortion. Monster Cable is used for internal wiring. High-frequency output level switches (-1, 0, +1 dB) let you adjust for room acoustics and listening position.
The enclosure looks like one box but is divided into separate compartments per driver. The woofer sections run as bass reflex with pipe ducts, using a JBL-developed approach called Imaginary Equivalent Tuning (IET). It varies the two enclosures' volumes and duct resonance frequencies to optimize low-frequency phase and sound pressure when playing music. The input terminals support bi-wiring, and a switch disconnects the internal network for a multi-amplifier setup with an external crossover. Rated specs: 4 Ω nominal impedance, 95 dB/2.83V/m output, 150W maximum input (I.E.C. shaped noise), frequency response of 35 Hz to 20 kHz at -6 dB (48 Hz to 18 kHz ±2 dB), and horn dispersion of 60° horizontal by 40° vertical. Each speaker measures 499 × 1,254 × 412 mm and weighs 89 kg.
Four finish options were offered: black high-gloss lacquer, Juglans californica (California walnut), madrone burl, and gray birds-eye maple. The BQ and MBX variant designations seen in listings correspond to these finishes, but the sources available don't document which code matches which finish.
The S5500 turns up on the secondhand market. A Japanese auction proxy listing shows it, and a Russian Avito listing for an MBX pair in Rostov-on-Don asked 590,000 ₽, described as "only from Japan, excellent condition, all original, grilles included." The model is also the subject of two videos on the "Музей Винтажной Техники" (Vintage Technology Museum) channel, published in December 2024 and April 2025. No professional period reviews, production totals, or common maintenance issues have surfaced in the available documentation. One owner selling a pair noted it's a speaker worth keeping if you have the space, which at 89 kg and 1.25 meters tall is a fair caveat.
Similar items on eBay
No exact JBL Project K2 S5500 listings are live right now — these searches show current JBL and similar vintage audio gear on eBay:
As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.
Related Models
- JBL 075
- JBL 077
- JBL 120Ti
- JBL 124A
- JBL 124H
- Braun AUDIO-1 (1965)
- Braun AUDIO-250 (1965)
- Magnavox Component Systems (1972)
- Acoustic Research AR (1967-1976)
- Acoustic Research 11