ONKYO D-908E

Commentary

The Tollboy type speaker system was developed by gathering together the speaker technology that Onkyo currently possesses.

The unit is a further flash-up version of the D-312E mounted unit that was evaluated in the European magazine "Revue du son".

A 16 cm cone type woofer by A-OMF Monocoque cone is mounted in the low range.
The A-OMF Monocoque cone has a 4-layer structure made of PEN fiber, aramid fiber, cotton, and aramid fiber. In addition, the twill structure of PEN fiber has succeeded in eliminating the resin between fibers, improving the rigidity and internal loss of the diaphragm. In addition, the center cap and diaphragm are integrally molded into a bowl-shaped body with no inflection point to further increase the rigidity and completely eliminate the cause of divided vibration.
The magnetic circuit is equipped with a 65 mm diameter voice coil and a large ferrite magnet of 1090g weight / 140 mm diameter to improve input resistance and sound quality.
In addition, by adopting an aluminum die-cast frame with an average thickness of approximately 6 mm and an artificial leather edge made of ultra-fine fibers with consideration for responsiveness and reduction of unwanted sound reflection, consideration is also given to noise removal down to the minute level.

A ring type tweeter using a ring type diaphragm with an outer diameter of 40 mm / inner diameter of 30 mm is mounted in the high range.
The ring diaphragm is driven by a 35 mm diameter voice coil arranged on the same axis. By using the circumference corresponding to the middle point between the outer edge and the inner edge of the diaphragm as the driving point, the split vibration of the diaphragm is completely suppressed, and clear high-frequency reproduction in which the piston motion region reaches almost 20 kHz is realized. The inside of the diaphragm is equipped with a newly designed shaved aluminum equalizer, and by its unique shape, the frequency characteristic is flatter than that of the ultra-high-frequency range.
In addition, anti-reflection measures around the diaphragm and the use of a back chamber shape that does not generate flutter echo have been taken to thoroughly eliminate noise.

The network circuit uses an isolated wiring method to separate the woofer and tweeter network circuits to prevent interference between the signals of each band. In addition, a circuit mounting technology that does not generate a potential difference in the ground line of each network is introduced to prevent masking of minute audio signals.
The capacitor is manufactured by WIMA in Germany.

The enclosure uses a bass reflex system, and the bass reflex duct uses an advanced Aero Acoustic Drive, a slit-type duct with unique technology.
This method not only attenuates unnecessary high-order noise components by adopting a long and narrow rectangular cross-section, but also achieves high-speed low-frequency playback because it is advantageous in terms of viscous resistance of the air. In addition, the enclosure and duct sections are separated from each other to minimize the effects of vibration.
The enclosure structure is designed to increase vertical strength by rounding the sides. In addition, by placing power wood in the appropriate position of thick material such as 30 mm thick baffle, sound trapping due to unnecessary resonance is eliminated.
The exterior is elaborately plated with silver heart material compared to the past.

The speaker terminal is bi-wired to take advantage of the isolated wiring network circuit by reducing the mutual interference between woofer and tweeter.
The terminal uses a brass machined gold plated terminal corresponding to a banana plug, and a short bar is attached.

Spikes and spike receivers are included, and by attaching the spikes, unnecessary resonance from the floor surface can be prevented.

Model Rating

Method	2-way, 2-speaker, Basref System, Tall Boy Type, Anti-magnetic Design (JEITA)
Units Used	For low band : 16 cm cone type For High Frequency : 4 cm Ring Type
Rated frequency range	28 Hz to 100 kHz
Max Input	2000W
Impedance	4 Ω
Output sound pressure level	83dB/W/m
Crossover frequency	2kHz
Internal volume	41 liters
Maximum external dimensions	Width 322x Height 1,040x Depth 380 mm
Weight	21.8kg