ONKYO D-77XX

Commentary

A speaker system based on the D-77X with further increased rigidity and no resonance.

A 31 cm cone type woofer with pure cross carbon diaphragm is mounted in the low range.
This diaphragm achieves high purity and high rigidity by using carbon fiber as a cone without mixing with other materials with inferior characteristics. In addition, the diaphragm is constructed with two layers of carbon sheets. They are overlapped with each other at an angle of 45 ° to increase the strength in all directions. In addition, the diaphragm is molded into a special shape curved cone to eliminate resonance while maintaining the rigidity of the diaphragm.
In addition, the magnetic circuit uses a magnet of size φ 140x φ 75x17tmm, magnetic flux density 11,700 gauss and total magnetic flux 155,000 maxwell, and the edge uses engineering elastomer with less characteristic change due to temperature and humidity.
In addition, an acoustic stabilizer, a heavyweight weight, is mounted on the underplate of the woofer to reduce unnecessary vibration.

A 12 cm cone type skoker made of pure cross carbon is mounted in the middle area.
The diaphragm has a 12 cm of 12 cm, it uses a two layer structure of carbon fiber sheet, which is thinner and lighter than woofer. In addition, a newly developed special polymer compound is introduced into the binding material for cone molding to further reduce weight. In addition, a unique vibration reduction technology has been introduced. Focusing on dispersing and eliminating high-frequency resonance peaks by changing the half apex angle of the cone (the depth of the cone), it uses a structure with two angles of 25 ° and 55 °.
The edge uses engineering elastomer as well as woofer.

A 2.5 cm dome type tweeter using plasma carbonite titanium is installed in the high range.
Plasma Carbonite Titanium is a titanium base material that has undergone surface hardening treatment using the plasma method. It forms a high-hardness ceramicized titanium and a carbonite layer, resulting in hardness 5.6 times higher than that of pure titanium. Unlike the conventional process of coating the surface of titanium, this plasma production method hardens the base material itself so that there is no boundary (interface) between the hardened layer and pure titanium, so durability and reliability are enhanced.
In addition, in order to eliminate resonance of the diaphragm, a reinforcement structure is added to the outer periphery of the diaphragm to obtain a strong resonance elimination effect. This flattens the high-frequency resonance peak at 30k to 50 kHz outside the audible band, suppresses adverse effects on the audible band, and improves the transient response characteristics in the audible band.

There is no level control attenuator in order to make the network circuit direct and eliminate the elements of time variation.
For the network parts, a choke coil containing silicon steel plate with high saturation level is adopted. In addition, interference between units and networks is eliminated by a circuit separation system and a centralized one point grounding.

Specially selected high-density, high-hardness particleboards are used for the enclosure, 40 mm for the front baffle, 25 mm for the rear baffle, and 20 mm for the side / top / bottom plate, with a vibration isolation group between the front baffle and the rear of the enclosure.
In addition, the front baffle is a round baffle with a large R. Moreover, decorative projections such as the model number emblem and level controller are removed and flattened to reduce the diffraction and reflection of sound waves.

There was a special speaker stand sold separately.
4-leg structure made of hard particleboards.

Model Rating

Method	3-Way, 3-Speaker, Bass reflex system, Bookshelf Type
Units Used	For low band : 31 cm cone type For Medium Range : 12 cm cone type For high-pass : 2.5 cm dome type
Playback frequency band	28 Hz to 45000 Hz
Crossover frequency	450 Hz, 3000 Hz
Max Input	230W(EIAJ)
Impedance	6 Ω
Output sound pressure	91dB/W/m
Cabinet internal volume	57L
External dimensions	Width 380x Height 670x Depth 363 mm (including RUNNET)
Weight	34kg
Separately Sold : Speaker Stand AS-77DX (2 Set, ¥ 37,000)
External dimensions	Width 390x Height 220x Depth 355 mm
Weight	7.5kg