Abstract: A speaker system comprises an acoustic panel. The acoustic panel is constructed of a plurality of thin plate-like sound absorbing panels provided close to the loudspeaker and arranged such that major surfaces thereof are disposed with a predetermined space therebetween so that the front space of the loudspeaker is opened for guiding a sound wave forwardly to radiate along the surface of the panels, while components of the sound wave having a radiation direction oblique to the major central axis of the sound absorbing panels are attenuated due to propagation through the sound absorbing panels. The sound absorbing panels are made of a porous sound absorbing material in which metal powders of Al, Ni, Cu, and others are sintered. In the case where one side of the acoustic panel is opened, it is preferable to provide a sound absorbing material at least at that opening and to further enclose the periphery of the sound absorbing material with a sound insulating material.

Abstract: A speaker system comprises a pair of speakers for a higher frequency range and a pair of speakers for a lower frequency range. The speakers for the lower range are disposed with a space d.sub.1 equal to the wavelength .lambda..sub.c of a division frequency f.sub.c of a reproduction frequency range, and speakers for the higher range are disposed with a space d.sub.2 =d.sub.1 /4 to d.sub.1 /2 in the middle of the lower frequency speakers. Another speaker system comprises a speaker for reproducing signals in a lower frequency range of a reproduction frequency range to be reproduced, and a speaker for reproducing a higher frequency range of the frequency range, wherein a sound path dividing construction is provided for dividing the sound path of each of the speakers into two paths to provide openings for the lower frequency range and the higher frequency range. The openings for the lower frequency range are disposed with a space d.sub.

Abstract: An improved ribbon-type speaker having an independent magnetic circuit unit and vibration system assembly to thereby reduce second harmonic wave distortion and to provide a speaker which is easy to assemble and disassemble. The case of the magnetic circuit unit can be used as a jig in assembling the magnetic circuit thereby largely reducing the number of steps and the number of tools needed in assembly. The ribbon-type speaker further incorporates advantageously recess portions in a supporting frame of the vibration system assembly together with semicircular cut-out portions provided at both ends of long sides of the opening in the supporting frame. The rigidity of the vibrating plate is thus enhanced and the deformation and elongation of the damper member of the vibration system assembly is reduced.

Abstract: A piezoelectric electro-acoustic transducer which includes a diaphragm having a piezoelectric property, a base plate of a stiff material, and a resilient backing member which is compressedly covered at one side with the base plate and brought into contact at the other side with the diaphragm to provide the diaphragm with resiliency and/or tension, characterized in that the base plate is provided at one side adjacent said backing member with a surface which has a concave and/or a convex curvature to provide the diaphragm with different suitable pressures through said backing member, whereby it has become possible to improve the frequency characteristics, particularly, the low frequency characteristics of the transducer and a high conversion efficiency thereof.

Abstract: An electro-acoustic transducer with a piezoelectric diaphragm which is backed with a plurality of different resilient members for imparting a suitable resiliency and/or tension to said diaphragm to highly improve its acoustic characteristics with a simple construction.