JBL 4660A Studio Monitor (circa 1992)

The JBL 4660A is a large-format, 2-way bass-reflex speaker system built for sound reinforcement and musical instrument use. The main feature is the Differentiated Coverage Horn (model 2346-1) mated to a 2426H compression driver. It has an odd shape, designed to project a square coverage area onto the floor when the speaker hangs slightly from the ceiling. The horn pattern is 110° to the front and 38° to the rear. JBL claimed that let a single speaker cover a space that would otherwise take three or more conventional high-frequency horns. The service area is based on a 2:2.75 width-to-depth ratio, and the hanging angle can be adjusted to suit different room proportions.

The low end comes from a 38 cm (15") cone woofer. audio-database.com lists the 2225H, but at least one eBay listing of a used unit shows a 2226HPL, so replacement drivers may have been swapped in over the years. The enclosure is 19 mm multi-layered plywood with a full polyurethane coating, chosen for acoustic performance and for durability on the road. The woofer is front-mounted, which was intended to keep the frequency balance good toward the back of a room.

Specifications from the Japanese catalog listing are as follows:

• Frequency response: 60 Hz – 21.5 kHz
• Allowable input: 150W continuous pink noise
• Impedance: 8 ohms
• Sensitivity: 99 dB/W/m
• Crossover: 800 Hz
• Dimensions: 607 W x 1,102 H x 518 D mm
• Weight: 61.2 kg
• Original price (Japan): ¥450,000 per unit, circa 1992

Documentation on the 4660A is thin. A two-page technical manual exists for the base 4660 model, and a Japanese blog review praised the 4660A for a "delicate, tense, realistic sound," but no substantive period reviews have surfaced. One owner on the audioheritage.org forums bought a 4660A from a church in Oregon and dealt directly with JBL Pro for replacement parts valuation. That at least confirms the company was still supporting the model well after its release. Collectors looking for a matching pair occasionally post want-ads - a French forum member was looking for a single 4660 to complete a pair - which suggests these are uncommon enough that finding one isn't always easy.

The "A" suffix's meaning isn't documented, and no production span has been confirmed. The circa-1992 pricing is the firmest date anchor available.

eBay Listings

Vintage GE Alarm Clock Radio Model 7-4660A General Electric

$15.73

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