ONKYO D-77
¥ 59,800 (1 unit, around 1986)
Commentary
This speaker system was developed with a thorough design policy that seeks purity in everything.
A 31 cm cone type unit is used for the low range.
For the diaphragm, a pure cross carbon diaphragm is used, in which the cone is composed of only carbon fiber without using any other materials.
The magnetic circuit uses a magnet with dimensions of φ 140x φ 75x φ 17 tmm, magnetic flux density of 11700 gauss and total magnetic flux of 155,000 maxwell.
A 12 cm cone type unit is used for the middle area.
A pure cross carbon diaphragm is used for the diaphragm. Because of its small diameter, it has a fine two layer structure with about twice the amount of carbon fiber per unit area compared with pure cross carbon of Woofer.
In addition, by applying high-frequency resonance cancellation technology, the half apex angle of the cone is partially changed into two types of 25 ° and 55 ° to suppress the peak, flatten the frequency characteristics, and improve the transient response.
A 2.5 cm dome type unit is used for the high frequency band.
The diaphragm is made of plasma-nitrided titanium, which is surface hardened by the plasma method.
Unlike general coating methods, there is no boundary between the nitride part and pure titanium part, so it has particularly excellent properties in durability and reliability.
In addition, high-frequency resonance cancellation technology for improving transient characteristics has been introduced to flatten the high-frequency peak by analyzing the shape of the diaphragm, enabling high-frequency reproduction with good resolution.
The enclosure uses specially selected high-density particle boards with 25 mm thickness for the front baffle and back plate, 20 mm thickness for the side plate, and sufficient internal reinforcement for a heavyweight cabinet.
A round baffle with 25 mm R on both sides has been adopted in order to suppress the diffracted phenomenon of sound waves. In addition, projections on the baffle surface such as the model number emblem and the level controller have been eliminated, and a gap has been created between the baffle surface and the sub RUNNET to eliminate the influence of reflection.
Model Rating
| Method | 3-Way, 3-Speaker, Bass reflex system, Bookshelf Type |
| Units Used | For low band : 31 cm cone type For Medium Range : 10 cm Cone Type For high-pass : 2.5 cm dome type |
| Playback frequency band | 28 Hz to 45000 Hz |
| Crossover frequency | 500 Hz, 2500 Hz |
| Max Input | 200W(EIAJ) |
| Impedance | 6 Ω |
| Output sound pressure | 91dB/W/m |
| Cabinet internal volume | 57L |
| External dimensions | Width 380x Height 670x Depth 348 mm |
| Weight | 26.5kg |