JBL 4312SX (circa 2000)

Name: JBL 4312SX
Brand: JBL

The 4312SX is an upgraded version of the classic JBL 4312 studio monitor, and it appears to have been built almost exclusively for the Japanese market. It was priced at ¥115,000 per speaker around 2000, with the matching JS-50 stands going for ¥25,000 each. JBL explicitly designed this model to be compatible with DVD-Audio and SACD, so it expanded the power range in the mid and high frequencies to handle those high-resolution formats.

What makes the 4312SX interesting is the driver technology. The low end is a 30 cm cone woofer (2213H) with an Aqua Plus coated pulp cone, a 75 mm copper ribbon edgewise-wound voice coil, and an SFG magnetic circuit in an aluminum die-cast frame. The midrange is where things get modern: a 12.5 cm pure titanium inverted dome (904Ti-1) with a neodymium magnet and a balanced-drive 37 mm voice coil. The tweeter is a 25 mm ripless pure titanium dome (TW025Ti) with a copper-coated aluminum voice coil and Ferrofluid damping, extended out to 40 kHz. The whole thing is a 3-way, bass reflex, bookshelf-type design in a walnut-finished cabinet with a 25 mm MDF front baffle, twin ports, and continuously variable attenuators for the mid and high drivers.

The record on this model is thin in places. No production year range is documented beyond "around 2000," and there's no real reception history in the Western press. What survives comes mostly from Japanese sources and owner communities. A Russian forum user reported settling on the 4312SX after auditioning Diatone, Pioneer, Onkyo, and Sansui three-way speakers. YouTube videos show them driven by 2A3 single-ended tube amps and used for long jazz listening sessions. One eBay listing describes a pair as "Fully Restored Excellent w/Grilles."

Known specifications:

- 3-way, 3-speaker, bass reflex, bookshelf type

- Frequency response: 40 Hz - 50,000 Hz

- Output sound pressure level: 93 dB (2.83V/1m)

- Impedance: 6 Ω

- Allowable input: 150W (RMS)

- Crossover frequencies: 900 Hz, 3800 Hz

- Dimensions: 362 × 597 × 299 mm (W×H×D)

- Weight: 20.0 kg

- Drivers: 30 cm cone woofer (2213H), 12.5 cm inverted dome midrange (904Ti-1), 2.5 cm dome tweeter (TW025Ti)