Denon SC-306 (c. 1981)

The Denon SC-306 is a 3-way, 4-driver bookshelf loudspeaker from the early 1980s. It was the flagship speaker in Denon's System 80 stereo component lineup. The July 1980 System 80 catalog lists it at ¥119,600. A Japanese database puts production at "around 1981" with a per-unit price of ¥59,800. The catalog figure may have been for a pair, or it may reflect a later revision. Sources agree on the ranking: the SC-306 sits above the SC-304 (¥89,600) and the SC-101 "Super Boy" (¥54,000) in the series.

The driver complement is substantial for a bookshelf design. A 30 cm cone woofer handles the low end, with the diaphragm mass reduced to 40g to improve transient response. The voice coil uses an aluminum bobbin and a heat-resistant adhesive rated for over 200°C, aimed at surviving continuous high-input sessions. The midrange is a 10 cm cone driver shared with the higher-grade SC-307. It is mounted in a light-alloy die-cast frame with an integrated back cavity to isolate it from woofer back pressure. High frequencies come from a pair of 5 cm cone tweeters, also from the SC-307, in a twin-drive arrangement that Denon claimed roughly doubled the linear range in the treble. Both mid and high ranges have continuously variable level controls.

The crossover sits at 500 Hz and 4 kHz. Rated frequency response is 30 Hz to 25 kHz, impedance is 8 Ω, sensitivity is 92 dB/W/m, and maximum input is 120W. The cabinet measures 376 × 680 × 349 mm and weighs 20.5 kg. A Japanese-language database (audio-database.com) notes the woofer and tweeter use a "sandwich support system" - each unit is clamped around its full circumference with uniform force to reduce inter-driver interference.

Documentation is thin beyond these specs. The only other corroboration comes from used-market listings: an Avito ad for a 1981 unit "in excellent condition," a HifiShark listing confirming the 30 cm woofer powers on, and a couple of Vietnamese YouTube/TikTok posts pairing the SC-306 with Onkyo and Denon amplifiers. No period reviews, owner write-ups, or detailed maintenance information have surfaced in English.

**Known specs:**

- 3-way, 4-driver bookshelf design (30 cm cone woofer, 10 cm cone mid, dual 5 cm cone tweeters)

- Frequency response: 30 Hz - 25 kHz

- Impedance: 8 Ω; sensitivity: 92 dB/W/m

- Maximum input: 120W; crossover at 500 Hz / 4 kHz

- Dimensions: 376 × 680 × 349 mm; weight: 20.5 kg

- Mid/tweeter level controls, continuously variable

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