DENON SC-907
¥ 65,000 (1 unit, around 1985)
Commentary
Speaker system using PCM diaphragm and α - boron diaphragm.
A 32 cm cone type woofer is installed in the low range.
The diaphragm is a polypropylene based PCM diaphragm with a special mixture of carbon graphite and mica. This diaphragm is approximately 2.5 times more rigid than the conventional woofer diaphragm and approximately 9 times more rigid than the paper cone.
6 cm hard dome type skoker is adopted for the middle area.
The diaphragm uses an α - boron diaphragm, in which boron compound and alumina particles are fused to the surface of the diaphragm in a porous state by plasma jet method on an aluminum base material. This diaphragm achieves approximately 10 times the internal loss compared to conventional metal diaphragm.
This α - boron diaphragm has been improved to a structure that directly radiates 100% of the sound of the diaphragm to enhance the mid-range.
The precision adjustment of the frame opening suppresses harmful resonance at the edge, and there is no need for an diffuser in front of the diaphragm, and only the original pure sound can be emitted.
In addition, it uses a push-pull double suspension with a push-pull structure for the edge and damper, greatly improving linearity.
A 2.5 cm hard dome tweeter with a diaphragm made of α -Boron is used for the high range.
As with the Skoka, it uses a structure that does not use a diffuser that directly emits sound, and it aims at flat reproduction with little coloring up to the super high frequency of 50 khz.
A large electrolytic capacitor dedicated to audio is used for the network.
The enclosure uses a rigid softwood particle board and a vibration-proof structure utilizing vibration analysis.
Model Rating
Method | 3-Way, 3-Speaker, Bass reflex system, Bookshelf Type |
Units Used | For low band : 32 cm cone type For Middle Area : 6 cm Dome Type For high-pass : 2.5 cm dome type |
Frequency characteristic | 30 Hz to 50 kHz |
Impedance | 6 Ω |
Maximum allowable input | 150W (program source) |
Mean output sound pressure | 92dB/W/m |
Crossover frequency | 800 Hz, 5000 Hz |
Level control | Continuously variable mid - and high-frequency range |
External dimensions | Width 370x Height 680x Depth 327 mm |
Weight | 23kg |