JBL 4645B Cinema Subwoofer

The JBL 4645B is a professional subwoofer from JBL's cinema and commercial sound line, built to go with the 8340 Control Series speakers. The design is plain workhorse: a single 18-inch (460 mm) driver in a vented enclosure, with a quoted frequency response of 32 Hz to 500 Hz. Sensitivity is rated at 94 dB (1W/1m) and nominal impedance is 8 ohms. Power handling is big - 500 watts continuous pink noise, 1000 watts continuous program - and the recommended amplifier power range is 500 to 1000 watts RMS. Mix magazine (February 1996, p.149) listed the 4645B as JBL's replacement for the earlier 4645 subwoofer in their cinema product line, and called it a cinema subwoofer.

The cabinet measures 470 x 600 x 546 mm and weighs 35 kg. Input is through Neutrik Speakon connectors. A 100 Hz crossover frequency is specified. Mix magazine (February 1996, p.149) listed the 4645B as JBL's replacement for the earlier 4645 subwoofer in their cinema product line, and called it a cinema subwoofer.

Past those specs, the record is thin. No production years, original pricing or detailed crossover topology have turned up in the available research. The 4645B appears to have been a purpose-built, no-frills extension of the 8340 system, the kind of cabinet that did its job in a cinema or commercial installation and drew little written comment.

Known specifications:

- **Type:** Vented (ported) subwoofer, passive cabinet

- **Driver:** Single 460 mm (18 in) low-frequency driver

- **Frequency response:** 32 Hz - 500 Hz

- **Sensitivity:** 94 dB SPL (1W/1m)

- **Power handling:** 500 W continuous pink noise; 1000 W continuous program

- **Recommended amplifier power:** 500 W - 1000 W RMS

- **Nominal impedance:** 8 ohms

- **Crossover frequency:** 100 Hz

- **Dimensions (H x W x D):** 470 x 600 x 546 mm

- **Weight:** 35 kg

- **Inputs:** Neutrik Speakon