抄録
The speaker of condenser type has an advantage over the speaker of moving coil type in high frequency region of acoustic waves, for in the former the driving force acts directly upon the whole of the vibrating diaphragm and the diaphragm can be made very light, less than a milligram per cm2. But for obtaining the response in medium and low frequency regions as high as in high frequency region, use of a large diaphragm, high direct bias voltage and high signal voltage becomes necessary, which is not practical.
Condenser type speakers with diaphragm made of ribbon-shaped vibrating units have been made. Because of a large electric capacity of the speaker and a large effective area of the diaphragm, the speaker can be driven by a direct bias voltage of 300400 volts and a signal voltage of 50_??_60 volts. Of these speakers, electric capacity, dumper and driving force are described and several frequency-response characteristics obtained experimentally are shown. These speakers have a nearly constant response over the range of 500-12000 c. p. s.
