Tannoy SGM-15B
A 15-inch Dual Concentric driver in a box small enough to fit a mid-sized control room. Tannoy's compact answer to engineers who wanted a primary monitor, not a wall.
Overview
The SGM-15B is the small one in Tannoy's Super Gold Monitor line, and "small" is relative. The cabinet measures 26½" H × 19¾" W × 18½" D, which is manageable by studio-monitor standards, but Tannoy put a 15-inch dual-concentric driver in it. That combination is the pitch, and Tannoy said so in print at the time: the SGM-15B was designed for users needing a small, yet powerful monitoring system.
Tannoy's own advertising in Mix (September 1989, p.28) framed the SGM-15B as the compact member of a family that already included the large-format twin-15" FSM-U and the T.E.C. Award-winning PBM Series. The ad said it established a higher level of performance for compact primary monitors, for engineers who needed a primary monitor that would fit in a mid-sized control room. The copy also leaned hard on the Dual Concentric story. The flare of the 15-inch low-frequency cone acts as a direct extension of the high-frequency compression driver, which Tannoy claimed produces the purest point source and eliminates the need for a separate horn. The geometry is real: one driver, one acoustic center, no lobing between a woofer and a tweeter that sit inches apart.
Period classifieds show where the SGM-15B was sold. TekCom Corporation in Philadelphia listed the SGM-15B reference monitors at $2,500 per pair, right next to the larger SGM-1000 15" Super Gold monitors at $2,600. That hundred-dollar gap suggests how Tannoy positioned the two: the SGM-1000 was the flagship, and the SGM-15B was the practical alternative for rooms that couldn't justify the bigger box. The same ad pages carried Otari MTR-12 tape machines and Meyer 833 monitor systems. This was studio gear sold through studio channels, not a hi-fi showroom.
The SGM-15B is a purpose-built professional monitor from the late 1980s, and it should be judged as one. It wants a properly treated room and a serious amplifier, and it will show up the shortcomings of a casual listening setup faster than it will flatter them. Anyone coming from home hi-fi should expect different priorities: accuracy over warmth, headroom over sweetness.
Key Features
The 15-Inch Dual Concentric Driver
The SGM-15B uses a 15-inch dual-concentric driver, designated the K-3809 in the period Recording Engineer documentation. Some sources give the driver as a "3839," and the OCR on the original magazine scans is not perfect, so confirm the exact model number against the unit itself before sourcing parts. The geometry isn't in dispute. Tannoy's Dual Concentric design places the high-frequency compression driver at the throat of the low-frequency cone, so the flare of the 15-inch woofer becomes a direct extension of the HF driver's horn. The result is a true point source, one driver and one acoustic center, which is why these monitors have a following in rooms where precise imaging matters more than a wide sweet spot.
Hard-Wired Crossover with High-Current EQ
The crossover uses the same hard-wired construction and high-current EQ switches common to the rest of the Super Gold Monitor series. That matters more to a maintenance tech than to a spec-sheet reader. Hard-wired crossovers are serviceable, and the high-current EQ section is part of what gives the SGM series its reputation for headroom rather than just output. Collectors who already own Super Gold Monitor components will find the crossover construction familiar.
A Cabinet Sized for Real Rooms
At 26½" H × 19¾" W × 18½" D, the SGM-15B is a compact primary monitor rather than a full soffit-mount main. That footprint is why the model exists. A studio can put a 15-inch point-source transducer in a near-field position or drop it into a soffit without dedicating a wall to it. The trade-off comes with any box this size holding a driver this large, and it's why the SGM-15B sits below the SGM-1000 in the line rather than replacing it.
Historical Context
The SGM-15B belongs to Tannoy's Super Gold Monitor series, and contemporary advertising positioned it as the compact member of a family alongside the large-format twin-15" FSM-U and the T.E.C. Award-winning PBM Series. Tannoy's Mix (September 1989, p.28) campaign pitched it as establishing a higher level of performance for compact primary monitors, for engineers who needed a primary reference that would fit a mid-sized control room. It was a professional monitor from the late 1980s, sold through studio channels and appearing in period classifieds next to tape machines and other control-room gear rather than in home hi-fi catalogs.
Production years for the model aren't documented in the available sources. "Late 1980s" is as close as the record gets, and the 1989 advertising and classified appearances are the firmest dates on file.
Collectibility & Value
The SGM-15B doesn't come up often, and when it does, it's usually as part of a studio clear-out rather than a collector's shelf piece. The documented original price is $2,500 per pair, from a 1989 TekCom classified in Mix. The same ad block listed an "SGM-15" at $2,600 alongside the "SGM-15B" at $2,500, so the two designations appear to have been used for different configurations or simply inconsistently. Current market values aren't well documented. At the time of the last capture, no exact Tannoy SGM-15B listings were live on eBay.
Buyers should look carefully at the low-frequency driver. One documented owner had re-coned the LF driver with Tannoy's "hard-edge" cone kit, a modification known to alter the T/S characteristics of the system. A re-coned example is not factory original, and it should be priced and evaluated that way. Original cones, intact crossovers, and unmodified cabinets are the things to check. Spare-parts availability and common failure modes aren't documented in the available record, so a buyer should assume the usual vintage-monitor caveats apply: crossover capacitors age, drivers can be re-coned, and cabinets can be re-veneered. None of that is confirmed here, but all of it is worth inspecting in person.
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