JBL 4312 MkII Control Monitor Speaker Pair – Grey – Restored – 1-Year Warranty

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

Professionally Restored by HQaudios – Fully Tested – Backed by Our 1-Year Warranty.

1. Overview

Up for sale is a pair of JBL 4312 MkII Control Monitor three-way studio monitor speakers, the 1990s evolution of JBL's legendary 4310/4311/4312 compact control monitor. The 4312 MkII keeps the classic 12-inch JBL 2213H white-cone woofer – now with a 3-inch copper voice coil – and pairs it with the 5-inch 104H-3 midrange driver and the 1-inch 052Ti titanium-dome tweeter in the familiar compact bass-reflex enclosure.

Compared with the original 4312, the MkII uses a revised crossover (2 kHz / 5 kHz), higher sensitivity (93 dB) and the modern titanium tweeter, giving a more extended and refined top end while retaining the direct, dynamic JBL monitor character. Independent midrange and high-frequency level controls on the front baffle allow the tonal balance to be tailored to the room and to the listener's preference.

This pair is the grey-finish (GY) version with black baffles and black grilles, and is presented as a professionally restored, fully tested and warranted set.

2. Key Highlights

• Authentic JBL 4312 MkII Control Monitor stereo pair (1990s production) – the classic 4312 studio monitor updated with a titanium-dome tweeter
• 3-way bass-reflex studio monitor – 12-inch JBL 2213H white-cone woofer with 3-inch copper voice coil, 5-inch 104H-3 midrange, 1-inch 052Ti titanium-dome tweeter
• Crossover 2 kHz / 5 kHz – 6 ohms nominal – 93 dB/2.83 V/m sensitivity
• 45 Hz – 22 kHz (−6 dB) frequency response – 100 watts RMS power handling
• Front-panel midrange and high-frequency level controls
• All original JBL drivers – cones and diaphragms in good condition
• Grey studio-finish (GY) cabinets with black baffles and black grilles – as pictured
• Every driver checked, crossover capacitors checked, RTA-verified frequency response and phase
• Professionally restored and tested by HQaudios
• Carefully packed for safe delivery
• Backed by a 1-Year HQaudios Warranty

3. Sound Character

The JBL 4312 MkII delivers the direct, dynamic and engaging presentation of the classic 4312 series with a cleaner, more extended top end from its titanium-dome tweeter. The 12-inch 2213H woofer provides a strong, punchy bass foundation, the 104H-3 midrange keeps vocals forward and articulate, and the 052Ti tweeter adds fine detail and air without the harshness of lesser metal domes.

With the level controls set flat the balance is lively and slightly forward in the JBL studio-monitor style; a small reduction of the midrange and high-frequency controls gives a smoother, more relaxed presentation for home listening. Rock, jazz, pop and film soundtracks are reproduced with the scale and impact that made the 4312 family a long-running studio favourite.

4. Cosmetic Condition

This JBL 4312 MkII pair is in very good restored cosmetic condition. Please review all photos carefully, as they are part of the description.

• Cabinets: Grey studio-finish cabinets, cleaned and detailed, with only light age-related marks remaining – as pictured.
• Front Baffles / Drivers: Black baffles with the white-cone 2213H woofer, 104H-3 midrange and 052Ti titanium tweeter – all six original JBL drivers, cones and diaphragms in good condition.
• Grilles / Badges: Black grilles re-made with new cloth and mounting pegs; JBL badge and "Model 4312MkII Control Monitor" front legend clean and legible.
• Controls / Rear Panel: Midrange and high-frequency level controls operate smoothly; rear terminals upgraded to new gold-plated binding posts.
• Stands: The stands shown in the photos are for display only and are not included.

5. HQaudios Restoration & Testing Process

Before Restoration

As received, this JBL 4312 MkII pair showed every sign of decades of use and storage. The cabinets were dirty and scuffed, with scratches and wear on the grey cabinet finish. The grilles had broken mounting pegs, cracked frames and torn cloth. The terminal cups were cracked and no longer gripped a cable. The foam surrounds had rotted and the cones and dust caps were faded and discoloured. Mounting screws and hardware were rusted, and the badges and rear labels were torn, faded or missing.

Each cabinet, cone, surround, and spider was then 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 (midrange and high-frequency level controls) were checked for burn marks or pitted contact surfaces.

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

During Restoration

Based on the inspection results, this JBL 4312 MkII pair was restored according to HQaudios' technical standards while preserving its original engineering and voicing.

The rotted surrounds were replaced (re-foamed) and the cones re-centered, and the cones and dust caps were cleaned and refinished to an even, original-style colour. The grilles were re-made with new mounting pegs, repaired frames and new grille cloth. The cracked terminal cups were upgraded to new binding posts. All rusted screws and mounting hardware were replaced with new, and the logos and rear labels were re-made to match the originals.

All drivers retain their original cones and diaphragms, which are in good condition; no driver required replacement on this pair.

The midrange and high-frequency level controls were cleaned and treated with contact cleaner and checked through their full range.

The grey-finish cabinets were cleaned, and all drivers, crossover boards, controls and terminals were cleaned and detailed.

After Restoration

Once restoration was completed, the pair underwent comprehensive testing under real operating conditions.

Frequency response was measured with an RTA (real-time analyzer) and a calibrated sound card to confirm a smooth, well-balanced response and close matching between the two speakers. Driver polarity was verified with a phase-reversal check to ensure both speakers play in correct phase, and the midrange and high-frequency level controls were checked through their full range. Finally, the pair underwent an extended real-world listening test with a wide range of music to confirm dynamics, tonal balance, and stereo imaging.

Only after completing HQaudios' restoration and testing process was the pair approved and prepared for its next owner.

6. Model-Specific Components

• Low Frequency Driver: JBL 2213H – 12-inch white-cone woofer with 3-inch copper voice coil
• Midrange Driver: JBL 104H-3 – 5-inch cone midrange
• High Frequency Driver: JBL 052Ti – 1-inch titanium-dome tweeter
• Enclosure: Bass-Reflex / Ported Bookshelf Monitor
• Crossover: Passive three-way network with 2 kHz and 5 kHz crossover points
• Controls: Independent midrange and high-frequency level controls
• Configuration: Mirror-imaged left/right pair

7. Specifications

Brand: JBL

Model: 4312 MkII Control Monitor

Type: 3-Way / 3-Driver Bass-Reflex Studio Monitor (Bookshelf)

Production: 1990s (4312 MkII)

Country of Origin: United States (JBL Professional design)

Finish: Grey studio finish (4312 MkII GY) with black baffles – as pictured

Color: Grey / Black

Low Frequency Driver: JBL 2213H – 12-inch white-cone woofer, 3-inch copper voice coil

Midrange Driver: JBL 104H-3 – 5-inch cone midrange

High Frequency Driver: JBL 052Ti – 1-inch titanium-dome tweeter

Crossover Frequencies: 2 kHz / 5 kHz

Nominal Impedance: 6 Ohms

Sensitivity: 93 dB / 2.83 V / 1 m

Frequency Response: 45 Hz – 22 kHz (−6 dB)

Power Handling: 100 Watts RMS

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

Enclosure: Bass-reflex (ported)

Configuration: Mirror-imaged stereo pair

Dimensions (W × H × D): 14.3 × 23.5 × 11.7 inches (each)

Weight: approx. 44 lbs (each)

Included: Matched pair with grilles – see What Is Included

Technical Note: The specifications above are for the JBL 4312 MkII version. They should not be confused with the original 4312, 4312A/4312B or the later 4312B MkII, 4312D, 4312E or 4312G models, which use different drivers and/or specifications.

8. What Is Included

• JBL 4312 MkII Control Monitor speakers – matched stereo pair (2 speakers)
• Black grilles (2)
• 1-Year HQaudios Warranty

Speaker stands, if shown in the photos, are for display purposes only and are not included. Only the items clearly shown in the photos or specifically listed above are included.

9. Video Test & Sound Demo

If you would like to see or hear the JBL 4312 MkII Pair in operation before purchase, please contact HQaudios directly.

When available, HQaudios can provide additional photographs, close-up images, operational videos, and sound demonstrations. Customers may also visit the HQaudios YouTube channel for restoration projects, product demonstrations, and listening sessions.

10. Suggested Pairing

Sansui AU-9500

The Sansui AU-9500 offers substantial vintage amplifier capability and can make a strong pairing with the JBL 4312 MkII for listeners seeking a classic Japanese amplifier and American studio-monitor combination.

Sansui 9090

The Sansui 9090 can serve as the centerpiece of a classic vintage receiver system with the JBL 4312 MkII, offering substantial power and a period-correct system aesthetic.

Marantz 2270

The Marantz 2270 provides a classic-period receiver option for the JBL 4312 MkII and can be an attractive choice for a vintage home listening system.

Final system matching should take into account amplifier capability, the JBL 4312 MkII's 6-ohm nominal impedance, room size, listening level, speaker placement, and the condition of all supporting equipment.

11. Basic Use Guide

• Connect the speakers to an amplifier or receiver appropriate for a 6-ohm nominal load.
• Observe correct left/right and positive/negative speaker-terminal polarity.
• Position the speakers securely on sturdy, stable speaker stands or an appropriate support surface.
• Use the mirror-imaged left/right configuration for optimal stereo imaging.
• Adjust the front-panel midrange and high-frequency controls carefully according to room acoustics and listening preference.
• Avoid excessive amplifier clipping or operation beyond the limits of the drivers.
• Keep the woofer, midrange, and high-frequency driver surfaces free from accidental contact or pressure.
• Protect the wood cabinet finish from excessive moisture, direct sunlight, and extreme temperature changes.

12. Trade-In Program

Do you have vintage audio equipment you'd like to trade in?

HQaudios welcomes trade-ins on receivers, amplifiers, speakers, cassette decks, reel-to-reel decks, turntables, and other classic audio equipment.

Simply send us photos and basic information about your equipment. Our team will review the item and discuss available trade-in options.

13. Build Your Vintage System / Combo Discount

Looking to build a complete vintage audio system?

HQaudios can help match the JBL 4312 MkII Pair with compatible vintage receivers, integrated amplifiers, power amplifiers, reel-to-reel decks, turntables, and other classic audio components.

Save $100 when purchasing these speakers together with a qualifying restored vintage audio component from HQaudios.

Please contact us before purchase so we can confirm availability and prepare a combined offer.

14. Shipping & Packaging

This JBL 4312 MkII speaker pair will be professionally packed by HQaudios for safe delivery. Because these are large and heavy vintage studio monitors, additional care will be taken during packing.

• Each speaker carefully wrapped and protected
• Heavy-duty boxes and protective packing materials
• Extra protection around front baffles, grilles, corners, controls, and driver areas
• Internal protection against movement during shipment
• Protective separation between the two speakers
• Tracking provided after shipment
• Signature may be required for delivery

15. 1-Year HQaudios Warranty

This JBL 4312 MkII speaker pair is backed by a 1-Year HQaudios Warranty for normal home use, subject to the terms and conditions of the warranty.

If you experience an issue, please contact HQaudios first. We are committed to helping our customers and will work with you to evaluate the issue and determine an appropriate solution.

Warranty coverage does not include misuse, improper amplifier connection, unauthorized repair, physical damage, cosmetic wear, blown drivers caused by excessive clipping or overdriving, shipping damage after delivery, incorrect wiring, incompatible equipment, or operation outside the manufacturer's intended specifications.

16. Customer Service

Once your speakers arrive, if you have questions about amplifier matching, speaker placement, connections, level-control adjustment, or general operation, please contact HQaudios.

Our team is happy to help you use the JBL 4312 MkII correctly and confidently as part of your vintage audio system.

17. Important Note for Vintage Audio Buyers

This is vintage audio equipment, and minor cosmetic signs of age should be expected. We do our best to describe and photograph each item accurately. Please review all photos carefully and contact us with any questions before purchase.

The JBL 4312 MkII is a 6-ohm nominal speaker system. Always use an appropriate amplifier or receiver and avoid excessive clipping or operating levels that may damage the drivers.

The JBL 4312 MkII should not be confused with the original 4312, the 4312A/4312B or the later 4312B MkII, 4312D, 4312E or 4312G models. Driver configurations and technical specifications differ between these versions.

Your satisfaction is important to us. Please contact HQaudios first if you need assistance after delivery.

HQaudios – Vintage Audio Restored with Care.

Professionally Restored • Fully Tested • Carefully Packed • 1-Year Warranty