JBL 4731A

The JBL 4731A is a compact screen channel loudspeaker from JBL Professional's Cinema Series, built to sit behind a movie screen. It's a two-way system with a 300 mm (12 in) cone woofer and a 25 mm (1 in) compression driver, loaded onto a one-piece 90° x 90° waveguide. The crossover splits the signal at 1200 Hz and 7000 Hz.

The specs below come from JBL's own Cinema Loudspeaker Product Guide and are corroborated by parts dealers. Frequency response is rated at 70 Hz - 20 kHz (± 3 dB), with a usable range from 50 Hz to 25 kHz at - 10 dB. Sensitivity is 93 dB SPL at 1 meter with 4.0 V (2.83 V pink noise), and nominal impedance is 8 ohms. Power handling is rated at 300 W continuous pink noise, 600 W continuous program, and 1200 W peak. JBL recommends driving it with 300-600 W into 8 ohms.

The 4731A sits in the "600 mm stage/channel" category of JBL's cinema lineup, alongside larger siblings like the 4732A and 4733A. It was clearly meant for smaller screens or venues where a compact footprint matters, but the record doesn't say much more about its market positioning. Period reviews are scarce. One brief mention in EQ Magazine (February 1995, p.102) describes a cinema installation context and offers no real commentary on the speaker itself.

What's known about the 4731A is basically its spec sheet. No original price, production years, dimensions, or weight have surfaced in the available documentation. Replacement diaphragms for the HF driver (part number D8R4731A) are still listed by parts suppliers, which suggests the model remains serviceable decades on.

Type: Compact 2-way cinema screen channel loudspeaker
Drivers: 300 mm (12 in) cone woofer; 25 mm (1 in) compression driver on 90° x 90° waveguide
Crossover: 1200 Hz and 7000 Hz
Frequency response: 70 Hz – 20 kHz (± 3 dB); 50 Hz – 25 kHz (– 10 dB)
Sensitivity: 93 dB SPL (1 m, 4.0 V / 2.83 V pink noise)
Impedance: 8 ohms
Power handling: 300 W continuous / 600 W program / 1200 W peak
Recommended amplifier: 300 – 600 W into 8 ohms