Abstract: A piezoelectric speaker (100) includes: a chassis (110) having a wall surface including an opening; a plurality of diaphragms including at least a first piezoelectric diaphragm and second piezoelectric diaphragms (120, 130a, 130b) which vibrate in phases opposite to each other when a voltage is applied; and a joint member (140a, 140b) which connects the first and second piezoelectric diaphragms (120, 130a, 130b) in a positional relationship such that the diaphragms are located at positions different from each other in a thickness direction, and one of the diaphragms is provided, in the opening of the chassis (110), to have one surface facing an outside of the chassis (110) and an other surface facing an inside of the chassis (110), and functions as a radiation plate which radiates a sound wave by vibrating at an amplitude generated by synthesizing amplitudes of the first and second piezoelectric diaphragms (120, 130a, 130b).

Abstract: A speaker device according to the present invention is a speaker device including a plurality of speaker units arranged in a line when seen from the front side of the speaker device. At least one of intervals between effective vibration regions of adjacent speaker units is set to a predetermined length. The predetermined length is a length that is set such that a difference between a distance from an end of one of the effective vibration regions, which form the at least one of intervals therebetween, to a listening position, and a distance from an end of the other of the effective vibration regions to the listening position can be less than half the shortest wavelength of a reproduced sound of each of the speaker units.

Abstract: A piezoelectric type loudspeaker, which achieves both space-saving and high sound quality without increasing the number of parts, is provided. In order to achieve this, the present invention includes: a piezoelectric element constructed of a piezoelectric material interposed between two surface electrodes; and a diaphragm of which at least one principal surface is provided with a print wiring and at least one principal surface is bonded to the piezoelectric element, and the diaphragm includes: a frame section; a vibrating section which is bonded with the piezoelectric element, and which vibrates; and at least one supporting section which connects the frame section and the vibrating section, and which supports the vibrating section, and either the frame section or the at least one supporting section includes at least one electrical resistance which is integrally formed to the print wiring, and which constructs, in combination with the piezoelectric element, a series-RC circuit.

Abstract: The speaker system according to the present invention is a speaker system in which a sound is emitted into a closed space from the back surface of a speaker unit, and has characteristic that gas in the closed space is physically adsorbed by a gas adsorber obtained by adding a binder to a porous material including a plurality of grains so as to perform molding. The speaker system according to the present invention is capable of reproducing, even when a small cabinet is used, low frequency sound while suppressing reduction in sound pressure level as compared to a conventional art.