JBL 2360A Bi-Radial Horn (Early 1980s)

A 24-pound fiberglass horn that throws 90 by 50 degrees of clean, articulate midrange. It was the compact workhorse of JBL's constant-directivity line.

Overview

At 24 lb (10.9 kg) net, the JBL 2360A Bi-Radial Horn doesn't look like much. It's a squat, dark fiberglass bell with a 24.5″ × 14.6″ mouth, and it fits under your arm like an awkward suitcase. But this is the piece that brought JBL's professional Bi-Radial series down to a size that made sense for real-world sound reinforcement. It was introduced in the early 1980s as the compact alternative to the larger 2365A and 2366A units in the same family. The 2360A became a fixture in cinema and touring sound. You'd find one bolted above a screen in a multiplex or flown in a stack at a festival, getting vocals and high-frequency detail out to a crowd without turning to mush.

The horn's claim to fame is constant directivity. Older radial horns narrowed their pattern as frequency rose, beaming like a flashlight. The 2360A's proprietary Bi-Radial flare geometry holds a 90° horizontal × 50° vertical beamwidth ( - 6 dB) across its operating range. That coverage holds down to approximately 800 Hz, which is where JBL intended you to cross it over. Below that point the horn goes omnidirectional, because the mouth isn't big enough to control directivity any lower. The result is a speaker that behaves predictably in a room, without the off-axis coloration that made older horns sound "honky" or piercing.

The frequency range is 500 Hz to 18 kHz, with a usable bandwidth to match. That's a wide window for a horn this size, and it's why the 2360A paired so naturally with JBL's 2390/2391 low-frequency horns. Together they formed a full-range constant-directivity system that could be bi-amped with a JBL 5234A or 5235 crossover. For DIY builders and cinema restorers, that combination is still a proven recipe.

Key Features

Bi-Radial Flare Geometry

The heart of the 2360A is its Bi-Radial flare — a curved, two-plane expansion that JBL developed to keep beamwidth constant rather than collapsing at the top end. It's not a gimmick; it's the difference between a horn that sounds like a megaphone and one that sounds like a studio monitor. The constant-directivity behavior means the power response stays flat through the crossover region, which is why JBL recommended an 800 Hz crossover with a 3rd-order Butterworth slope — that combination yields flat power response, not just flat on-axis response. The horn is described as clean, articulate mid/high that integrates well in a variety of boxes.

Rotatable Coverage Pattern

The 2360A is meant to be mounted with its long axis horizontal for 90° × 50° coverage. Rotate the horn 90° and the pattern flips to 50° horizontal × 90° vertical. That's useful for installations that need tall, narrow coverage, such as under-balcony delays, without buying a different horn. The flange measures 26.8″ × 17.1″ (681 mm × 434 mm), which gives you the bolt pattern to work with. The 14.2″ (361 mm) depth keeps it manageable in tight fly spaces.

Fiberglass-Reinforced Plastic Construction

JBL built the bell out of heavy-duty 5/16″ fiberglass-reinforced plastic, or FRP in the trade. It's durable, it doesn't resonate the way sheet metal can, and it holds up to touring and permanent installation alike. Recording Engineer (June 1980, p.119) announced the new Bi-Radial constant coverage horns - the 2360, 2365, and 3266 - specifically for fixed installation applications, noting the heavy-duty FRP construction. The 2360A's mouth edges are designed to sit in contact with neighboring units, so you can array them side-by-side or in clusters with continuous aperture coverage and no gaps.

Driver Compatibility

The 2360A accepts 1.5″ throat compression drivers with 2″ voice coils, specifically JBL's own 2445 and 2446 units per the literature. Those drivers have the thermal capacity and clean output to make use of the horn. The recommended 800 Hz crossover point lines up with the horn's constant-directivity limit, so you're always operating where the pattern is controlled. For bi-amp setups, the 5234A or 5235 crossover handles the split.

Historical Context

The 2360A arrived as part of JBL's professional Bi-Radial series in the early 1980s. It slotted between the smaller 2350A below it and the larger 2365A and 2366A above. It was the compact option, the one you reached for when the big horns wouldn't fit the budget or the building. JBL designed it to pair with the 2390/2391 low-frequency horns, creating a two-way, full-range constant-directivity system that could cover everything from cinema dialogue to live rock vocals.

Sound reinforcement was moving toward predictable, arrayable systems, and constant-directivity horns made large-format sound work in difficult rooms. Mix (November 1988, p.95) noted a touring system equipped with 2360 Series horns paired with 2225 low-frequency loudspeakers in 4508 and 4507 enclosures, with 8216A systems for under-balcony ceiling delays. By the late 1980s, the horns were also showing up in cinema installations like the Mann's Chinese Theater, where Mix (July 1985, p.120) documented JBL stage sound systems in use.

Collectibility & Value

There's no original price on record for the 2360A, and no current market valuation from the reference sources. The horn is popular among DIY builders and cinema-sound restorers, who value it for what it was designed to do: deliver clean, articulate mid/high output that integrates well into a variety of boxes. The FRP construction is durable, and these horns don't rot or corrode the way metal or wood can. The main maintenance concern isn't the horn but the compression driver bolted to it. That means eventual ferrofluid replacement in drivers that use it, which is standard upkeep for any ferrofluid-cooled driver and not unique to this horn.

For someone building a period-correct JBL sound reinforcement system or restoring a vintage cinema installation, the 2360A is a sensible building block. It's not a collectible in the sense of a rare tube amp. It's a tool that still does its job, and the used market reflects that. A horn with a pair of 2445 or 2446 drivers attached is the makings of a proper constant-directivity mid/high section that will outperform a lot of modern boxes at a fraction of the cost.