JBL 4842

The JBL 4842 is a two-way, vented cinema screen loudspeaker from JBL Professional's 4800 Cinema Series — the line that explicitly replaced the earlier 4600 series, with the 4842 itself positioned as the successor to the 4670. It was designed for placement behind perforated cinema screens, as a main screen channel in multi-speaker theater installations, typically paired with 4832 or 4833 surrounds and a 4642A subwoofer.

The driver complement is well documented: a 15-inch 2226H woofer in a vented enclosure tuned to 45 Hz, crossed over at 1100 Hz to a 2425H compression driver mounted on a bi-radial horn. The crossover is an internal passive network, the DN-4842. JBL's catalog figures rate the system at 99 dB sensitivity (1 W @ 1 m), 8 ohms nominal impedance, 300 W continuous / 1200 W peak power handling, and a frequency response of 55 Hz to 16 kHz (−10 dB). Recommended amplifier power is 600 W into 8 ohms, with maximum SPL rated at 124 dB continuous and 130 dB peak.

The catalog record carries a few internal inconsistencies worth flagging. The dedicated 4842 page lists the cabinet at 527 mm high, 508 mm wide, and 419 mm deep, weighing 22.7 kg; the generic 4800 series page gives different figures (737 mm high, 451 mm deep, 24.04 kg). Likewise, the crossover is stated as 1100 Hz on the dedicated page but 1 kHz on the series page, and the horn coverage angle appears as both 90° × 40° and 60° × 40°. I've used the dedicated model page's figures above, as it's the more specific source, but the discrepancies are real and unresolved in the available documentation. The 4842's use in professional cinema installations is noted in passing in Mix (1989, p.102) coverage of high-SPL touring and installed sound systems of the period.

Beyond the catalog specs, the record is thin. No production years, original pricing, or third-party reviews have surfaced, and there's no documentation of the model appearing in specific real-world theater installations. What survives is a solid, professional-grade specification sheet for a workhorse cinema loudspeaker — the kind of box that did its job behind the screen, night after night, without anyone writing much about it.

Type: Two-way vented cinema screen loudspeaker
LF: 2226H 15" woofer, enclosure tuned to 45 Hz
HF: 2425H compression driver on 2342 bi-radial horn
Crossover: Internal passive DN-4842, 1100 Hz
Frequency response: 55 Hz – 16 kHz (−10 dB)
Sensitivity: 99 dB (1 W @ 1 m)
Impedance: 8 ohms
Power: 300 W continuous / 1200 W peak
Weight: 22.7 kg (50 lb)