JBL 4847

A 73-kilogram cinema speaker with 18-inch woofers, a terminated horn, and 98 dB sensitivity (some sources list 97 dB).

Overview

The JBL 4847 is a three-way cinema speaker, and JBL designates it a "Cinema Wide" model. It is built to anchor wide-screen presentations in both indoor and outdoor cinema environments. It measures 1512 x 880 x 597 mm and weighs 73 kg. This is professional equipment sold through commercial channels, not a bookshelf speaker, and you won't find it at a big-box retailer.

The 4847 is built around a straightforward, brutalist philosophy: move air, control dispersion, and take abuse. The driver complement pairs 18-inch low-frequency drivers with a horn-loaded high-frequency driver, all driven through a terminated horn design. The exact number of bass drivers is not specified in the documentation. The sensitivity is rated at 98 dB (some sources list 97 dB), which means it doesn't need a nuclear power plant behind it to produce serious output — a pair of these with a modest pro amplifier will fill a room with authority that consumer speakers simply cannot match. It's the kind of speaker that makes you understand why JBL's cinema line has been a staple in theaters for decades.

It's sold as a "Cinema Loudspeaker" by dealers like bax-shop.de and thomann.de. The spec sheet reads like a checklist for professional installation: 8-ohm nominal impedance, Speakon input connectors, MDF construction, and a frequency response of 40 Hz to 18 kHz. There's no veneer, no grille cloth color options and no finish choices. It's a black box.

Key Features

18-Inch Low-Frequency Drivers and Horn-Loaded HF

The heart of the 4847 is its driver array. 18-inch low-frequency drivers handle the bottom end, paired with a horn-loaded high-frequency driver for the top. This is classic JBL cinema architecture — big cones for displacement, a horn for efficiency and controlled dispersion. The horn-loading isn't just for output; it's about pattern control, ensuring the high frequencies reach the listening area with the same intensity as the lows. The terminated horn design referenced in the spec sheets is part of this package, helping to manage the transition between the drivers and reduce the harshness that poorly integrated horns can exhibit.

90 x 50 Degree Coverage

One of the most important specs on the 4847 sheet is the dispersion: 90 x 50 degrees. This is a deliberate design choice for cinema use. The wide 90-degree horizontal pattern covers a broad seating area, while the tighter 50-degree vertical pattern keeps energy aimed at the audience rather than bouncing off the ceiling and floor. For a home cinema, this means you get a forgiving sweet spot — move around the room and the image stays intact, which is exactly what you want when you're watching a film with a group rather than sitting in a single critical-listening chair.

Speakon Input Connectors

The 4847 uses Speakon inputs. These locking connectors are the industry standard for touring and installed sound. They don't pull out accidentally, they handle high current, and they make daisy-chaining multiple cabinets straightforward. If you're coming from home audio, you'll need an adapter or a cable swap. It's a small detail, but it shows the speaker was designed for crews.

MDF Construction

The cabinet is MDF, chosen for its density and consistency. At this size and weight the enclosure needs to be dead, because any panel resonance would color the sound and muddy the low end. MDF provides the mass to keep the box quiet while the drivers work. It's not glamorous, but it suits a speaker that's going to be mounted, flown, or stacked and expected to perform the same night after night.

Performance and Power Handling

With a frequency response of 40 Hz to 18 kHz, the 4847 covers the audible range with room to spare. The low end is where these big cabinets earn their keep — 18-inch drivers move serious air, and the sealed or ported alignment (the fact sheet doesn't specify) is tuned for cinema impact rather than hi-fi subtlety. The top end extends to 18 kHz, which is sufficient for modern film soundtracks; you're not getting the ultrasonic extension of some esoteric tweeters, but you're also not paying for it.

Power handling is rated at 300 W continuous and 1200 W peak, according to studio-sound.fi. That's a wide gap between RMS and peak, which is typical for cinema speakers. They have to take transient impact like explosions, gunshots and door slams, while continuous levels stay lower. With 98 dB sensitivity (some sources list 97 dB), a quality 200-300 W per channel pro amp will drive these into serious output. The 8-ohm nominal impedance is friendly to most amplifiers, though you'll want real current delivery to get the best out of the 18-inch drivers.

The crossover is listed at 800 Hz, though some sources note a two-point crossover of 800 Hz / 2.5 kHz. The discrepancy likely reflects different system configurations, with the lower point splitting the woofers from the horn and the higher point possibly indicating a separate compression driver or a three-way arrangement. Either way, the crossover points are sensible for the driver complement and keep the horn out of the frequencies where it would sound strained.

Design and Build

The 4847 is big. At 1512 x 880 x 597 mm it's roughly the size of a small refrigerator, and at 73 kg it's a two-person lift at minimum. You'll place it once and it will stay there. The size follows from the driver complement. The 18-inch woofers need cabinet volume to work properly, and the horn needs baffle area to avoid diffraction issues.

Construction is MDF, as noted, which keeps the cabinet inert. The finish is utilitarian, made for dark cinema rooms and flown clusters. There's no walnut veneer option and no fabric grille in designer colors. It's a black box that looks like it belongs in a theater.

Intended Use and Positioning

The 4847 is explicitly positioned for cinema use — bax-shop.de lists it for "indoor and outdoor cinema" applications, and the "Cinema Wide" designation tells you it was designed for wide-screen formats. This isn't a studio monitor for critical nearfield listening; it's a system for filling a room with sound that matches the visual scale of a film. The 90 x 50 degree coverage pattern is optimized for a bank of seats, not a single sweet spot, and the power handling is designed for sustained output over a two-hour feature, not just a 20-minute listening session.

In a home context, the 4847 makes sense for a dedicated theater room where you want genuine cinema-grade equipment rather than home theater in a box. Amplifier matching, crossover settings and room treatment all matter. JBL's cinema loudspeakers, including models like the 4873 and 4866 that share the 4847's design lineage, were used in professional touring applications such as the Neil Diamond arena tour and stadium installations like the 1988 Winter Olympics at McMahon Stadium, as documented in contemporary trade publications Recording-Engineer (April 1986, p.52) and Sound and Communication (April 1988, p.45).

Final Thoughts

The JBL 4847 is a specialist tool. It's big, heavy, and uncompromising in its design goals. The 98 dB sensitivity (some sources list 97 dB) makes it efficient, the 18-inch drivers give it low-end authority, and the horn-loaded high-frequency driver projects with clarity. The Speakon connectors, MDF construction, and 90 x 50 degree coverage all point to professional cinema installation as the primary use.

There's no production year, original price, or user review data in the available documentation — this is a speaker that lives in the commercial channel, specified by integrators and installed by crews, not reviewed by audiophile magazines. What the spec sheet tells you is enough: this is a serious piece of cinema engineering from a company that has been doing this since the 1940s. If you're building a theater and want the real thing, the 4847 deserves a look.