JBL 4751A
The JBL 4751A is a professional loudspeaker system from JBL's "Sound Power Series," priced at ¥570,000 per unit around 1992. It's a 3-way, 5-speaker bass reflex design for large-format sound reinforcement. You'd find these cabinets clustered in a club or concert venue, not a living room. It's a tri-amp system, so it expects separate amplification for the low, mid, and high bands, with recommended crossover points at 1.2 kHz and 7 kHz.
The driver lineup is big. Two 30 cm cone woofers (the 2206H) handle the lows. The midrange comes from a horn-loaded compression driver, a 2445J with a 10 cm titanium diaphragm on a 2380A flat-front biradial horn. Two 2404H biradial ring radiators take the highs. It's essentially the 4750A with one more 2404H added for high-frequency output. The enclosure is wedge-shaped, so multiple cabinets can be arrayed side-by-side, and each additional enclosure extends horizontal coverage by 30 degrees. The directional characteristic is rated at H90° x V40° (-6 dB).
The specs look good on paper. Playback band is 32 Hz to 20 kHz (-10 dB). Output sound pressure levels are 98 dB/2.83V/m for the low section (129 dB max), 112 dB/2.83V/m for the mid (133 dB max), and 105 dB/2.83V/m for the high (124 dB max). The low section is rated for 1,200W (AES Standard, 60-600 Hz), the mid for 150W continuous program, and the high for 40W continuous program. Impedances are 4 Ω for the low section and 16 Ω for both mid and high. Input connections are dual Neutrik NL8MPR speakON connectors. The cabinet measures 620 x 996 x 440 mm and weighs 65 kg.
The 4751A is designed for tri-amping, but an optional crossover network, the N4751AP (sold separately), could be inserted to convert it to a bi-amp configuration, splitting low frequencies from the mid/high band. The system was also designed to be paired with JBL sub-bass systems - the 4745A, 4748A, 4785A, and 4788A.
Documentation on this model is thin. No production years are firmly established, and no period reviews or owner opinions have surfaced in the available record. What's known comes largely from Japanese audio database entries and the occasional secondhand listing — one Vietnamese video seller memorably describes it as a "super dinosaur mobile disco" that gets "the whole neighborhood high." That's not a technical evaluation, but it does capture the 4751A's character: a serious, high-output professional tool built for one job — getting loud and covering a room.
- Type: 3-way, 5-speaker, bass reflex
- Drivers: 2x 2206H (30 cm woofer), 2445J + 2380A (horn mid), 2x 2404H (horn high)
- Frequency response: 32 Hz – 20 kHz (-10 dB)
- Crossover: 1.2 kHz, 7 kHz (recommended)
- Impedance: L 4 Ω / M 16 Ω / H 16 Ω
- Dimensions: 620 x 996 x 440 mm
- Weight: 65 kg
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