Denon SC-A3 (c. 1982)
The Denon SC-A3 is a 2-way, 2-speaker bass reflex bookshelf speaker from the early 1980s. It originally sold for ¥37,000 per unit. The paper trail is thin. Most of what's known comes from a single Japanese spec database, and even the exact production years aren't confirmed.
The low end is handled by a 26 cm cone woofer with a polymer diaphragm, chosen for light weight and appropriate internal loss. Denon gave the cone a concentric corrugation rib developed through vibration analysis. The company claimed roughly twice the rigidity of a flat cone in the same material. A large flat damper and a strong magnetic circuit were used for power linearity, and an aluminum die-cast frame suppresses vibration. The baffle is fixed with eight 8 mm bolts and nuts, which let Denon leave off the low-range cover entirely.
The tweeter is the standout feature. It's a 2.5 cm hard dome with an α-Boron diaphragm. Per the spec sheet, the diaphragm was made by fusing boron compound and alumina particles onto a 30-micron aluminum foil with an ultra-high temperature plasma jet, building it up to 20 microns. Denon claimed rigidity about three times that of a titanium diaphragm, with internal loss roughly ten times that of a typical metal diaphragm. A continuously variable high-frequency level control is provided on the speaker.
The enclosure is a rigid particle board cabinet with a black finish. Internal volume is 40 liters, with an optimally designed duct. The grille is a special knit fabric in "monsoon grey." Full specs: playback frequency band 35 Hz to 50 kHz, maximum allowable input 100W (program source), crossover at 3 kHz, 6 Ω impedance, and 92 dB/W/m sensitivity. Dimensions are 316 × 570 × 323 mm (W×H×D). Weight is 14 kg.
A note on the "SC-A3L" variant. A Dutch classified listing shows units described as spray-painted gold and calls them a "gold edition." This appears to be an aftermarket finish modification rather than a factory variant. The official model is the SC-A3. The same listing paired the speakers with a Denon DSW-3L subwoofer, likely a separately sold companion.
One Russian owner reported shipping a pair to a buyer in Spain. The trip took two months, and the buyer was reportedly satisfied. Beyond that, reception and maintenance history are essentially undocumented.
- Type: 2-way, 2-speaker, bass reflex bookshelf
- Woofer: 26 cm cone (polymer diaphragm)
- Tweeter: 2.5 cm α-Boron hard dome
- Frequency range: 35 Hz – 50 kHz
- Max input: 100W (program)
- Crossover: 3 kHz
- Impedance: 6 Ω
- Sensitivity: 92 dB/W/m
- Dimensions: 316 × 570 × 323 mm
- Weight: 14 kg
- Original price: ¥37,000 (per unit, c. 1982)
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