SONY SS-7090
¥ 27,000 (a set of two cars, around 1974)
Commentary
This speaker system uses a low-distortion magnetic circuit and newly developed cone paper.
A 20 cm cone woofer is installed in the low range and a 6.5 cm cone tweeter is installed in the high range.
The diaphragm is made of Scandinavian pulp, and Sony's proprietary papermaking technology is used to increase rigidity and expand the range of piston motion.
In addition, we clarified that abnormal noise of an extremely large level is radiated in a band 2 to 3 times of the upper limit frequency due to abnormal vibration of the voice coil bobbin and the joint between the bobbin and the cone. We adopted a dust-proof cap with a large sound insulation effect to suppress abnormal noise radiation. In addition, we made a notch in the center of the center pole and added thick copper plating or copper cap to the notch to eliminate nonlinear distortion caused by magnetic material.
A newly developed adhesive made of special rigid resin is used in order to cope with large output shafts. In addition, a metal bobbin (winding frame) is used in the woofer to increase the allowable input.
In addition, a thin special rubber cloth is applied to the edge for airtight treatment to eliminate the valley that tends to occur near 400 Hz. In addition, high-purity imported copper foil processed with special resin is used for the lead wire to prevent disconnection to extend the life.
In order to bring out the performance of the unit, a large air-core coil with low DC resistance is used in the network section.
Hard particle board is used for the enclosure.
By carefully examining the material, thickness and reinforcement method, resonance such as box rumbling is reduced.
The Sa RUNNET uses a Beat Orange colored urethane grill net.
Model Rating
| Method | 2-Way, 2-Speaker, Airtight Type, Bookshelf Type |
| Unit | For low band : 20 cm cone type For high pass : 6.5 cm cone type |
| Frequency characteristic | 45 Hz to 20 kHz |
| Output sound pressure level (new JIS) | 88.5dB/W/m |
| Impedance | 8 Ω |
| Maximum allowable input | 30W(Weighted pink noise) |
| Crossover frequency | 6kHz |
| External dimensions | Width 290x Height 508x Depth 272 mm |
| Weight | 8kg |