Pioneer CS-755
¥ 69,800 (1 unit, around 1977)
Commentary
A 3-way speaker system using beryllium diaphragm.
A newly developed 30 cm aperture unit is used for the woofer.
The cone paper has a shallow straight shape, high strength enough to withstand moderate internal loss and back pressure, a wide piston motor cortex range, a low fo of 18 Hz, and an expanded low-frequency playback limit.
A ferrite magnet of 156 mm diameter is adopted for the magnetic circuit, and a pure copper cap is attached to the center pole to reduce the strain.
The voice coil is a long type with excellent linearity that suppresses the generation of strain even under Dainyu force. An aluminum-alloy mass balancer is attached to the upper part of the bobbin to balance the weight of the cone and voice coil and to prevent dynamic deformation of the cone neck due to vibration, thereby eliminating the generation of strain.
The edge uses a deformation roll Cross Edge, which improves the connection boundary conditions between the cone and the edge and causes buckling, resulting in a good linear operation.
The frame is made of aluminum die-cast.
The mid-range uses a 65 mm dome shape. The material is a hard aluminum alloy with a thickness of 22 μ m and beryllium is evaporated to a thickness of 60 μ m. It is lightweight and has excellent rigidity.
In addition, the top of the dome is cut off to eliminate resonance.
The suspension is a dual suspension system with tangential edges on both inner and outer sides of the dome.
In addition, the outer edge of the diaphragm is covered with an aluminum die-cast flange to control the chamber between the flange and the diaphragm to provide an edge equalization effect.
In order to deal with the back pressure of the diaphragm, a high-density resin back chamber is installed in the rear part. The chamber is filled with a special sound absorbing material to prevent standing waves and to make the chamber non-resonant to effectively prevent the reaction to the diaphragm.
The tweeter uses a 25 mm diameter beryllium dome diaphragm to ensure a wide playback band of up to 40000 Hz and excellent directivity.
A tangential edge with good linearity is adopted, and the edge is covered with an aluminum die-cast flange to provide an edge equalizing effect. This compensates for the dip in the characteristics of the dome alone, and realizes excellent directional characteristics without the equalizer on the front of the diaphragm.
The enclosure is a completely sealed type consisting of 20 mm thick, high-density, high-elasticity softwood particle board with 24 mm thick lauan plywood.
In addition, the same conifer particle board reinforcement is effectively arranged inside to suppress plate vibration.
The devices used in the network are carefully selected. In particular, the choke coil is made of a laminated core made of silicon steel and covered with thick copper wires. It is a soft distortion type with little loss and strain, and the strain does not increase rapidly even when Dainyu is applied. Metallized paper capacitor with little loss are mainly used as capacitors.
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Model Rating
| Method | 3-Way, 3-Speaker, Airtight Type, Bookshelf Type |
| Units Used | For low band : 30 cm cone type For Middle Area : 6.5 cm Dome Type For high-pass : 2.5 cm dome type |
| Impedance | 6.3 Ω |
| Playback frequency band | 30 Hz to 40000 Hz |
| Output sound pressure level | 90dB/W/m |
| Max Input | 100W |
| Crossover frequency | 650 Hz, 5500 Hz |
| External dimensions | Width 375x Height 665x Depth 315 mm |
| Weight | 26kg |