Tamotsu Ito

Moving voice coil transducer with diaphragm having concentric sections of opposite curvature

An electroacoustic transducer in which a diaphragm of a loudspeaker for converting an electrical signal into an acoustic signal comprises a lower section and an upper section thereof which are split axially of a center pole of a magnetic circuit. The lower section of the diaphragm has a concave-curved surface such as an exponential-curved surface while the upper section of the diaphragm has a parabolically-curved surface. A roll is provided at the joint area of the upper and lower sections of the diaphragm. In this manner, a high-band resonance frequency of the loudspeaker is raised to a high frequency and Q of high-band resonance is lowered to broaden a reproduction frequency range of the loudspeaker.