Audio Database

SC-5000
Commentary

This floor-type speaker system was developed over a period of four years to accommodate digital sources.
Twelve peripheral and related patents and two utility models have been awarded for realizing this speaker.

A 40 cm cone type woofer is installed in the low range.
The High-M / P vibration plate is used for the vibration plate. While taking advantage of the excellent properties of paper, structural rigidity is greatly increased. This vibration plate is made by blending refined ramie fiber with wood pulp, which has a higher Young's modulus than wood pulp. After careful beating treatment to control the distribution of fiber length, it is manufactured by a newly developed special papermaking technology into an integrated structure with a rib pattern. High rigidity is obtained. This rib pattern is formed by concentric circular and radial ribs, and rigidity is improved by about 2 times compared with conventional ones. At the same time, peaks and dips are suppressed, and increase of harmonic distortion is suppressed, and flat frequency characteristics are realized.
Outer diameter φ 220 mm, 4.8x10 for the drive system5Using a large ferrite magnet of maxwell and 11,000 gauss, it achieves high efficiency with output sound pressure level of 98 db and instantaneous maximum sound pressure level of 128 db.
In addition, the center pole of approximately φ 100 mm is provided with a hole part in order to reduce non-linear distortion of air due to sudden change of air flow and impedance change near the lowest resonance frequency at large amplitude. This center pole is equipped with a special shape control ring made of copper in order to reduce current distortion of the drive part. The current distortion is improved by more than 10 dB, and cavity resonance inside the magnetic circuit is prevented to prevent distortion.
The large diameter voice coil of φ 100 mm uses polyamide imide resin coated ribbon copper wire with excellent electrical conductivity. It is wound on a Nomex resin bobbin with special high heat treatment to clear the instantaneous maximum allowable input of 1 kW. In addition, the voice coil is designed to move vertically in a magnetic field at all times to prevent drive nonlinearity.
In order to provide higher durability for the edge and damper supporting the diaphragm, we use a material that combines phenolic resin with a special resin that is highly resistant to degradation. This material ensures high durability and moderate viscoelasticity, and significantly reduces the Q of abnormal edge resonance and diaphragm resonance. In addition, the waveform of the edge and damper of φ 170 mm adopts a special linear motion corrugate curve, and realizes symmetrical linearity against the amplitude of the front and rear of the diaphragm.
The diaphragm, voice coil and damper are installed with almost no clearance at the cone neck to prevent radial flexural vibration of the voice coil and to stabilize the high frequency characteristics.

It has a 15 cm cone type mid-range in the mid-range.
The High-M ・ T diaphragm is made of a woven fabric of high-elasticity fibers, which is a kind of polymer compound, reinforced with epoxy resin, and realizes wide-band internal loss and high Young's modulus. The Young's modulus is about three times that of paper, and internal loss is also large. This enables expansion of the piston motion region and reduction of resonance Q in the divided resonance region, resulting in flattening of sound pressure frequency characteristics.
A large ferrite magnet with a maximum diameter of 140 mm is used in the drive system to achieve high efficiency. In addition, a copper control ring is provided in the center pole to improve second and third harmonic distortion due to current distortion by 12 dB, and cavity resonance in the magnetic circuit is eliminated to achieve low distortion and high efficiency.
The voice coil of φ 40 mm is designed to be as heat-resistant as a woofer. Heat-resistant ribbon copper wire is used for weight reduction and high input resistance.
The support system for the edge and damper uses a unique linear motion and corrugate curve similar to Woofer. In addition, a resin-treated woven fabric containing a special resin in phenol resin is used to maintain the balance of the vibration system, expand the linearity, and improve durability.

A 5 cm cone type tweeter is installed in the high range.
The diaphragm uses the same High-M / T diaphragm as the mid-range diaphragm. It is a semi-dome type diaphragm. The center dome portion is made of a special aluminum alloy 30 μ m thick. The area of the dome portion is increased and the sound pressure radiation balance with the diaphragm portion is examined. The neck portion of the diaphragm is folded back to further increase rigidity, prevent flexural vibration of the voice coil, and prevent distortion due to Dainyu force. The center dome is filled with ultra-fine glass fibers to provide vibration control and sound absorption, and flatten sound pressure frequency characteristics.
In order to keep the distance from the voice coil to the diaphragm as short as possible, the diaphragm has a rational structure that eliminates dampers and improves response. In addition, the diaphragm is surrounded by a フィックスドエッジ and sandwiched with rubber to eliminate the disturbance of characteristics caused by end reflection and improve directivity.
The magnetic circuit employs a strontium ferrite magnet with an outer diameter of φ 120 mm to increase efficiency, and is equipped with a unique control ring with improved sound-pressure frequency characteristics and impedance characteristics by reducing current distortion and preventing cavity resonance. The voice coil is a bobbin with a diameter of 25 mm, which is made of a special aluminum alloy with a thickness of 30 microns and treated with alumite. Copper-coated ribbon-type aluminum wire treated with polyamide-imide resin is wound uniformly around the bobbin. This reduces weight and improves high-frequency characteristics and provides high input resistance.
In particular, the tweeter, which requires precision machining, performs precision cutting of special aluminum alloy plate, and the vibration system is assembled on this plate with precision jigs and tools, and assembled on the drive part.

In the network section, the circuit constant is based on -12dB/oct., and phase correction is performed according to the sound latitude characteristics and the sound pressure synthesis state of each unit. After hearing test, the latest parts are carefully selected and determined.
The capacitors used are mainly large metallized film capacitors with low loss. Two or more capacitors are connected in parallel for luxurious use. Four types of capacitors are selected according to the bandwidth of each unit.
The coil used for the woofer is an L-type silicon steel plate with a high purity copper wire of φ 1.4 mm wound firmly in consideration of power loss. The coil used for the mid-range tweeter is an air-core coil with little distortion even for large input.
In addition, in order to minimize loss due to circuit resistance, the printed circuit board circuit is eliminated and direct connection is used.

Equipped with level control for middle and high frequencies.

The enclosure is set to 185L, which drives a 40 cm woofer optimally in a bass reflex system. Each dimension ratio is adopted to minimize the generation and influence of standing waves. In addition, two types of sound absorbing materials are installed at the optimum position to eliminate standing waves.
In addition, the cabinet vibration mode is made into a sandwich structure with robust side plates. The side plates are 35 mm thick with 3 types of high density particle boards of 10 mm thick, 10 mm thick and 15 mm thick to reduce plate resonance, and the center core is composed of a surface layer with especially high density.
The baffle plate and top, bottom and back plates are made of 25 mm thick high-density particle board, and are firmly tightened by side plates from both sides.

A multi-channel terminal is also provided so that each unit can be driven by a dedicated amplifier.

Model Rating
Method 3-Way, 3-Speaker, Bass Reflex System, Floor Type
Units Used For low band : 40 cm cone type
For Medium Range : 15 cm cone type
For high-pass : 5 cm cone type
Frequency characteristic 25 Hz to 30 kHz
Impedance 8 Ω
Maximum allowable input 300W (program source)
1 kW (instantaneous maximum)
Average output sound pressure level 97dB/W/m
Crossover frequency 400 Hz, 3.2 kHz
Level control Continuously variable mid - and high-frequency range
External dimensions Width 572x Height 925x Depth 445 mm
Weight 70kg
Unit Characteristics
Unit Woofer Mid-range Tweeter
Average output sound pressure level 98dB/W/m 97dB/W/m 97.5dB/W/m
Lowest resonance frequency 36Hz 150Hz
(with enclosure installed)
1.25kHz
Maximum allowable input (program source) 300W 300W 300W
Instantaneous maximum sound pressure 128dB/m
(200 Hz, 1 kW)
127dB/m
(1 kHz, 1 kW)
122.3dB/m
(5 kHz, 300W)
Playback frequency band Fo ~ 4 kHz Fo ~ 15 kHz Fo ~ 30 kHz
Recommended cutoff frequency (-12dB/oct) 500 Hz or less 350 Hz or more to 5 kHz or less 2 kHz or more
Weight 14.4kg 3.2kg 2.6kg
Remarks When using a network with less attenuation than -12dB/oct, the maximum allowable input is reduced (especially the tweeter is about 100W).