Technics SB-501 ￥39,800(1台、1973年発売) ￥46,800(1台、1974年頃)
These speakers were made for Japanese market only. Sound is very pleasant, detailed and rich
Dome type 3 way speaker system developed by combining the advancement of technics’ acoustic technology. The 30 cm cone type Woofer is carried in low-pass. The cone paper used for the diaphragm prevents split resonance by lowering the beating degree (standard for knowing the degree of leakage volume)) to increase the internal loss. Furthermore, in order to increase the density, the surface is coated with a special resin, the surface is hard and strong, the back side is light structure. For the magnetic circuit, a 4-layer voice coil using a light aluminum wire and a large ferrite magnet with 145 φ are adopted. By increasing the force coefficient, we realized a design that has plenty of flexibility in setting fo and Qo, improving efficiency and improving distortion characteristics. Urethane edge is adopted as an edge. The midrange has a 15 cm dome-shaped midrange. The diaphragm is provided with a roll type free edge and a back cavity is furthermore equipped. As a result, fo is reduced to 230 Hz to improve low-frequency playback ability. Moreover, by using double damper method, rolling phenomenon which tends to occur at large input is suppressed. The 10 cm dome tweeter is carried in the high region. A titanium diaphragm is adopted as a diaphragm, and by using a newly developed processing technology, 20 μm thick ultra-thin titanium foil is realized. In addition, by adopting titanium diaphragm, we succeeded in weight reduction by 30% compared with conventional aluminum type. Titanium foil is also adopted for the edge part, and we succeeded in lowering fo to the low frequency of 1.7 kHz. Edge resonance that tends to occur in low frequencies is suppressed with a special braking agent. Independent level control is carried in the midrange and the high region respectively. The enclosure is sealed. Tweeters were replaced with Monacor dt-352nf, resulting in a more detailed impressive treble. Crossover were refreshed with Matsushita and Nichicon new Bipolar capacitors, resulting a in clearer sound.
20 Hz to 30000 Hz Impedance 8 Ω Output sound pressure level 92 dB / W / m Maximum input 45 W Crossover frequency 600 Hz, 4000 Hz (12 dB / oct) Level control For mid range: +2 to 0 to -6 dB For high range: +2 to 0 to -6 dB Dimensions Width 380 x Height 660 x Length 324 mm Weight 23 kg