Audio Database

Scepter 300 Image
Commentary

A sound field type speaker system with a 3-way rear radiator system for indirect sound generation on the back to enhance the rich atmosphere and sense of presence unique to the live Symphony Hall.

In addition to the normal 3-way system, the Scepter300 adds a rear radiator for reflected sound only for the band where energy is insufficient. By increasing the sound radiated backward, energy characteristics are made uniform.
In addition, in order to realize the three points of Onkyo's design policy of expanding the dynamic range, expanding the playback range, and expanding the listening area, we are working to improve the quality of the system by introducing new technologies from both software and hardware aspects, such as the development of a magnesium alloy diaphragm and the development of a listening area measuring method and an energy response measuring method as design methods.

A 38 cm cone type woofer is installed in the low range.
In order to cope with the expansion of the dynamic range and to prevent bell vibration at high power, the rotary sheet-making cone with increased rigidity in the circumferential direction of cone paper is adopted. In addition, the heat radiation effect and heat resistance characteristics are improved by adding a reinforcing die-cast cap considering the heat radiation effect. The rigidity in the circumferential direction is increased approximately twice by the rotary sheet-making cone. In addition, the characteristics are improved by impregnating special resin into the cone paper, and at the same time, the rigidity and airtightness of the cone paper are increased.
The magnetic circuit uses a strong magnet with a magnet size of 180 φ x95 φ x20tmm, a magnetic flux density of 11,500 gauss and a total magnetic flux of 258,000 maxwell, and a long voice coil with an aperture of 76 mm.
In addition, a double damper made of polyimide fiber material, which does not change with time, is used for large input.

The mid-range is equipped with a composite squaker that combines a magnesium alloy diaphragm with a 10 cm cone.
With this composite diaphragm, we have achieved two and a half times the thickness and nearly seven times the strength of the conventional diaphragm, as well as a reduction in weight.
The magnetic circuit uses a magnet with dimensions of 140 φ x75 φ x17tmm, total flux density of 12,000 gauss and total flux density of 127,000 maxwell, and a voice coil with a large diameter of 65 φ mm. In addition, the edge section uses a double support structure that supports a magnesium-alloy diaphragm and carbon cone respectively, ensuring stable operation even when Dainyu is in use.
In addition, a back cavity with a volume of 0.7L and a minimum resonance frequency of 240 Hz is installed in the squaker.

A 2.5 cm dome type tweeter with a magnesium alloy diaphragm is mounted in the high range.
In this diaphragm, the foam rubber for braking, which had been used as a strapping in the inner surface of the dome part in order to suppress high-frequency resonance in the past, is removed, and dramatic improvement in efficiency of 4 to 5 dB and wide-band characteristics are realized.
In addition, we are working to improve the energy characteristics of the tweeter region, which is on a decreasing trend compared with the woofer band and other regions. We are working to improve this by developing and adding new equalizers.
In addition, magnetic fluid is injected into the gap of the magnetic circuit in the same way as before to suppress temperature rise of the voice coil, improve input resistance characteristics, and reduce harmonic distortion. In addition, the plate is shaped so that magnetic flux is easily concentrated, and all magnetic flux is concentrated in the voice coil.

The rear radiator is a 3-way structure to compensate for the high-frequency RUNNET of each front unit. It is cut at 45 ° to the top and rear of the enclosure so that it does not directly affect the characteristics of the front speakers. In addition, for low-mid radiators, a diffuse plate, which also serves as a reflection plate, is installed in the secondary radiator frame to prevent wraparound.
For the Low-Mid, a 10 cm cone unit with a delta-olefin diaphragm is used as a radiator to compensate for sound energy in the high range of the woofer. The sound energy is expanded over a wide range by an diffuser incorporated in a sub RUNNET frame.
Four 7 cm cone type speakers are used for Mid-High. They are mounted on a frame with an angle of 30 ° to the baffle surface. Two of them are directed upward to the rear surface and the other two are directed upward to the left and right for uniform rear radiation.
For Super High, we use a unit that combines a ring-shaped diaphragm driven by a 35 mm diameter voice coil with a conical horn with a three dimensional rotation angle of 90 °.

Equipped with a bi-amplifier drive terminal, only the rear radiator can be disconnected and connected separately.
It can be used when you want to increase the energy of the indirect sound component or when you want to change the frequency characteristics of the indirect sound component with a graphic equalizer according to the acoustic characteristics of the room.

Equipped with independent level control for the Skoka Tweeter and each rear radiator.

Model Rating
Method 6-way, 9-speaker, sound field type bass reflex system
・ Bookshelf type
Units Used For Low Band : 38 cm Cone Type (W3821A)
For Middle Range : 10 cm Composite Type (MD1010C)
For High Range : 2.5 cm Dome Type (TW319C)
Low-Mid : 10 cm Cone Type (MD1013B)
Mid-High : 4 x 7 cm cone (TW724A)
Super-High : Ring Type (TW950A)
Playback frequency band 22 Hz to 45000 Hz
Max Input 150W
Instantaneous maximum input 1500W
Duration of 0.1 sec, repetition time of 1 sec
Saturation value measured at burst wave)
Impedance 6 Ω
Crossover frequency 450 Hz, 3500 Hz
Level control Skoka tweeter and each rear radiator independent type
Output sound pressure level 91dB/W/m
Internal volume 120L
External dimensions Width 514x Height 893x Depth 473 mm
Weight 50kg