JBL 4315B/4315BWX (1980)
The JBL 4315B is a 4-way, 4-speaker bass reflex bookshelf monitor introduced to Japan in 1980. It is the unit-modified successor to the 4315A. Three of the four drivers changed from the earlier model. The low band uses a 30cm cone woofer (2203H), the middle-low band a 20cm cone mid-woofer (2108H), and the middle-high band a 13cm cone squawker (2105H). The high band stays with the horn-type 2405 tweeter. Crossover points are 400 Hz, 2 kHz, and 8 kHz, and the rated frequency response is 35 Hz to 20 kHz ±3 dB. Nominal impedance is 8 ohms, sensitivity is 89 dB/W/m, and allowable input is 60W (network). Each enclosure measures 521 × 854 × 327 mm and weighs a hefty 47.6 kg.
The enclosure is ported (bass reflex) and has support metal fittings on the back, so the speaker can be suspended if needed. Two finishes were offered. The 4315B came in gray with a black grille, and the 4315BWX in walnut with a blue grille. The blue-fronted versions are the ones collectors tend to seek out today. The original Japanese retail price was ¥400,000 per unit for the 4315B and ¥410,000 for the 4315BWX (circa 1981).
The broader 43XX series was established in 1973, when JBL formally split its professional and consumer lines. The 4320 became the milestone monitor that defined the series' reputation. The 4315B carried that professional monitor tradition into the 1980s. Formal period press reviews of this specific model are scarce in the available record.
One known real-world issue turned up in a 2016 blog post by KA7OEI, who documented a woofer "breakup" problem in a pair of 4315Bs. It is the kind of age-related driver failure collectors of this era should watch for. Aftermarket replacement grilles in various fabric colors are available from at least one supplier. A pair with custom walnut stands was listed on Audiogon at $4,500. A Yahoo Auctions listing for a JBL 4315 (model unclear) with walnut stands closed at ¥201,300 in July 2022.
Known Specs
- Type: 4-way, 4-speaker, bass reflex, bookshelf
- Woofer: 30cm cone (2203H)
- Mid-woofer: 20cm cone (2108H)
- Squawker: 13cm cone (2105H)
- Tweeter: horn-type (2405)
- Frequency response: 35 Hz – 20 kHz ±3 dB
- Crossover: 400 Hz / 2 kHz / 8 kHz
- Impedance: 8 ohms
- Sensitivity: 89 dB/W/m
- Allowable input: 60W (network)
- Dimensions: 521 × 854 × 327 mm
- Weight: 47.6 kg
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