JBL 2390 Bi-Radial Horn

Born in the golden era of professional audio, the JBL 2390 isn’t just a horn—it’s a precision instrument for sound projection. Combining a 300mm (12-inch) rectangular exponential horn with a folded-plate acoustic lens, it delivers a tightly controlled 100° horizontal by 45° vertical dispersion pattern. Engineered for high-frequency duties above 800 Hz, it can stretch down to 500 Hz when mounted with proper baffling, making it a favorite in both cinema and live sound rigs where clarity and directionality matter.

Specifications

Type	Folded-Plate Acoustic Lens with Rectangular Exponential Horn
Components	2309 Horn + 2310 Lens Assembly
Coverage Pattern	100° horizontal x 45° vertical
Frequency Range	Above 800 Hz (down to 500 Hz with baffle)
Sensitivity	107 dB (1W/1m, 4V into 16Ω, warbled 0.8-2.5 kHz)
Throat Diameter	50 mm (2 inch) - accepts 2" drivers natively
Adapter Available	Model 2327 throat adapter for 25mm (1") drivers
Nominal Q	2 (2 kHz octave band)
Horn Dimensions	191 x 267 x 305 mm (7½ x 10½ x 12 in)
Lens Dimensions	178 x 505 x 117 mm (7 x 19⅞ x 4⅝ in)
Total Weight	5.5 kg (12 lb)

Design Overview

The 2390 is a masterclass in acoustic control, marrying the 2309’s 12-inch rectangular exponential horn with the 2310’s folded-plate lens. The result? A bi-radial dispersion pattern that’s wide enough to cover audiences laterally while keeping vertical energy in check—critical for minimizing reflections in large venues. The lens handles horizontal dispersion at 100°, while the horn itself governs the tighter 45° vertical spread. For clean performance through the crossover zone, a proper baffle is non-negotiable. And when mounting, the lens is typically left exposed—its folded plates need clear air to do their job without edge diffraction or masking.

Mounting Options

Engineers love the 2390 for its adaptability. Whether flying it in a line array or tucking it into a custom enclosure, the horn plays well with different setups. The MA25 mounting kit delivers everything needed for secure external installation—baffle, brackets, hardware—while integration into bespoke cabinets remains a solid option, provided vertical plane baffling is maintained. The key is preserving the horn’s acoustic integrity, and that starts with how it’s mounted.

Low Frequency Operation

Though optimized for use above 800 Hz, the 2390 can dip down to 500 Hz when the situation calls for it. In motion picture sound systems, where low-mid punch matters and vertical control is less critical, it holds its own. The trick? Proper baffling in the vertical plane to prevent pattern distortion. It’s not a subwoofer, but with the right crossover and enclosure support, it extends impressively for a horn of its size and purpose.

Compatible Drivers

Featuring a 50mm (2-inch) throat, the 2390 pairs naturally with JBL’s 2" compression drivers—think the 2420, 2421, or 2441 series—delivering the power handling and efficiency expected in pro environments. But it’s not limited to big drivers. With the Model 2327 throat adapter, it opens the door to 1-inch models like the LE85 or 2425, offering flexibility for different system designs without sacrificing performance.

Applications

This is a horn built for the big leagues. From the booming soundtracks of 1970s cinema to high-SPL music reinforcement in touring systems, the 2390 carved its niche in professional sound. It thrived in commercial installations, cinema speaker arrays, and studio monitoring setups where accurate dispersion and high output were non-negotiable. Even today, restorers and vintage audio enthusiasts seek it out for period-correct theater builds and high-fidelity live rigs.

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Documentation

Lansing Heritage - Comprehensive JBL specifications, photos, and historical documents
HiFi Engine - JBL manuals, service documents, and brochures
Audio Karma JBL Forum - Community discussions and restoration guides