JBL 4315 (1975)

A compact 4-way studio monitor developed as the smallest in JBL’s professional line.

Overview

The JBL 4315 is a 4-way, 4-speaker bass reflex studio monitor introduced in 1975, designed as the most compact model within JBL’s Studio Monitor series. It features a dedicated mid-woofer enclosure to reduce driver interference and offers front-panel level controls for mid-low, mid-high, and high-frequency ranges. Available in gray or walnut finishes, the 4315 was marketed for professional and high-end consumer use, with a brochure issued in 1974 ahead of its release.

Specifications

Playback frequency band	35 Hz to 20 kHz ± 3 dB
Crossover frequency	400 Hz, 2 kHz, 8 kHz
Impedance	8 Ω
Output sound pressure level	89 db (New JIS)
Allowable input	60W (continuous program)
Enclosure volume	73.8 liters
Mid-Woofer enclosure volume	2.8L
External dimensions	Width 520x Height 850x Depth 280 mm
Weight	41kg
Unit Low Band	30 cm Cone Type (2203A)
For Medium Low Band	20 cm Cone Type (2108)
For Middle and High Areas	13 cm Cone Type (2105)
For High Pass	Horn Type (2405)

Design

The 4315 uses a bass reflex enclosure with an internal mid-woofer chamber to minimize interference between drivers. It features front-panel level controls for mid-low, mid-high, and high-frequency sections, allowing fine-tuning of the sound. The system is a 4-way, 4-speaker design with a bookshelf-type form factor and was offered in gray or walnut finishes.

Context

Developed as the smallest model in JBL’s Studio Monitor lineup, the 4315 was positioned for professional monitoring and high-fidelity home use. A product brochure was released in 1974, ahead of its 1975 market debut.

Market

A 1994 classified ad listed a pair of JBL 4315 speakers in walnut/BO finish for $750, indicating their presence in the secondhand market over a decade after release.

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