JBL 4312B Control Monitor Speakers Pair – Professionally Restored – 1-Year Warranty

JBL 4312B Control Monitor – classic JBL 3-way studio monitor

12-inch woofer, 5-inch midrange and 1-inch dome tweeter

Front-panel midrange and high-frequency level controls

45 Hz – 20 kHz frequency response, 91 dB sensitivity

Woofer voice coils re-centered; new surrounds, gaskets and dust caps on the woofers

Cabinets refinished with veneer repair and PU lacquer

Backed by our 1-Year HQaudios Seller Warranty

Before Restoration

The JBL 4312B pair was carefully inspected upon arrival to evaluate its mechanical, electrical, and cosmetic condition.

Each cabinet, cone, surround, and spider was checked for originality and for glue joints that had loosened or shifted with age. Every driver was tested by hand for voice-coil rub – a scratching noise or a stiff, binding cone indicates a shifted or heat-damaged voice coil. The DC resistance of every driver was checked against its nominal impedance. The crossover networks were examined for bulging or leaking capacitors, each capacitor was measured against its original value (within 10% tolerance), and the level controls, wiring and terminals were inspected.

Inspection Findings: The cabinets showed scratches and small dents, the badges were scratched, and the cabinet interiors and terminals were dusty. The woofers had voice-coil rub and dented dust caps, the midrange drivers and tweeters had deteriorated surrounds, and the L-pads needed attention.

The inspection results were used to determine the work required for this specific pair.

Technical Condition

Woofers: Original 12-inch woofers – voice coils re-centered, new surrounds and dust caps

Midrange & Tweeters: Original JBL drivers – new surrounds and dust caps

Crossover Networks: Repaired; capacitors measured against original values

Level Controls: Cleaned and repaired

Phase: Polarity checked on both speakers

Brand: JBL

Model: 4312B Control Monitor

Type: 3-Way Studio Monitor Loudspeaker

Years of Production: 1989 – 1990

Drivers: 12-inch woofer, 5-inch cone midrange, 1-inch dome tweeter

Crossover Frequencies: 1.5 kHz / 7 kHz

Frequency Response: 45 Hz – 20 kHz

Sensitivity: 91 dB (1 W / 1 m)

Nominal Impedance: 8 Ohms

Recommended Amplifier Power: Up to 100 W continuous

Controls: Front-panel midrange and high-frequency level controls

Dimensions (each): approx. 14.3 W x 23.5 H x 11.7 D in

Weight (each): approx. 53 lbs

Only the items specifically listed above are included. No stands are included; any stands, bases or platforms shown in the photos are for display only. Speaker cables and other accessories are not included.

SHIPPING & PACKAGING

Your vintage audio equipment will be professionally packed by HQaudios using protective materials appropriate for its size, weight, and construction. Large or heavy items may be palletized and shipped by freight when required for safer transportation.

1-YEAR WARRANTY & CUSTOMER SUPPORT

Your purchase is backed by our 1-Year HQaudios Seller Warranty (this is an HQaudios warranty, not a JBL manufacturer warranty). Our team provides support before and after your purchase. If you have questions about setup, operation, compatibility, or your order, please contact HQaudios for assistance.

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