JBL 2390 Bi-Radial Horn
The JBL 2390 is a horn for sound projection. It combines a 300mm (12-inch) rectangular exponential horn with a folded-plate acoustic lens, and it gives a controlled 100° horizontal by 45° vertical dispersion pattern. It is built for high-frequency duty above 800 Hz. With proper baffling it can go down to 500 Hz. It was 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 marries the 2309's 12-inch rectangular exponential horn with the 2310's folded-plate lens. The pattern is bi-radial. It is wide enough to cover audiences laterally and keeps vertical energy in check, which minimizes 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 required. The lens is typically left exposed when mounting, because its folded plates need clear air to work without edge diffraction or masking.
Mounting Options
Engineers like the 2390 for its adaptability. It can be flown in a line array or tucked into a custom enclosure. The MA25 mounting kit supplies what is needed for secure external installation - baffle, brackets, hardware. Mounting in bespoke cabinets is also an option, provided vertical plane baffling is maintained. The horn's acoustic integrity has to be preserved, and that starts with how it is mounted.
Low Frequency Operation
The 2390 is optimized for use above 800 Hz, but it can go 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. It needs proper baffling in the vertical plane to prevent pattern distortion. It is not a subwoofer, but with the right crossover and enclosure support it extends low for a horn of its size and purpose.
Compatible Drivers
The 2390 has a 50mm (2-inch) throat. It pairs with JBL's 2" compression drivers, such as the 2420, 2421, or 2441 series, for the power handling and efficiency expected in pro environments. It also takes smaller drivers. With the Model 2327 throat adapter, it accepts 1-inch models like the LE85 or 2425, which gives some flexibility for different system designs.
Applications
The 2390 found its place in professional sound, from 1970s cinema soundtracks to high-SPL music reinforcement in touring systems. It was used in commercial installations, cinema speaker arrays, and studio monitoring setups where accurate dispersion and high output were required. Restorers and vintage audio enthusiasts still seek it out for period-correct theater builds and 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