A piezoelectric cone-type speaker having a multiple structure in which a plurality of piezoelectric elements and speaker diaphragms individually coupled to them are coaxially or multi-axially arranged. It has a wide frequency range. A cushioning member is interposed between one diaphragm and another so that each element is isolated from the vibrations of another element.
A coaxial type composite loudspeaker has at least three coaxially arranged loudspeakers of different opening diameters and different allocated frequency bands. This composite loudspeaker can reduce the synergistic interference among the component loudspeakers to prevent deterioration of the characteristics of the respective component loudspeakers and also can centralize the sound sources of the component loudspeakers upon a single axis to enhance the localization of sound image and improve the directivity on the horizontal plane.
A multi-driver, coaxially mounted loudspeaker array utilizing a high frequency bi-morph driving element (tweeter) that is preferably contained within the air-core of the voice coil former of a lower frequency loudspeaker (woofer). The outwardly extending conical edge of the high frequency device's diaphragm is annularly fixed by a compliance to the inner surface of the referenced voice coil former or to the woofer diaphragm which extends outwardly therefrom. Alternately, the bi-morph element is attached to other dynamic parts of the woofer such as the dust cap or at the rim of, or otherwise on, an extension of the former. In this mode, the bi-morph element may first be mounted to a section of a cylinder or cone which acts as a frame of the same circumference or more/less than that of the coil former. Thereafter, the frame is mounted to the end of, over or inside the coil former, or any moving part of the woofer.
The present invention provides a speaker device in which assembly is easy, and which has high sensitivity and low distortion. The speaker device comprises a frame member, a piezoelectric element to which a sound signal is applied, a diaphragm attached to the piezoelectric element, a coil for boosting the sound signal, and a damper attached to the piezoelectric element in the opposite side face to the diaphragm to elastically support the piezoelectric element. The coil is wound with respect to the frame member, and the damper is attached on the frame member.
A piezoelectric speaker including a plurality of piezoelectric vibrating elements, each including a piezoelectric vibrating plate and a weight connected to near the point of center of gravity thereof through a viscoelastic layer, and having the vibramotive force designed to be taken out of the outer edge thereof, which are connected at their peripheral ends to each other through connectors, one of said elements being connected at its peripheral edge directly to a cone type acoustic radiator to give thereto a vibramotive force mainly in a high-frequency portion, and the remaining elements adjacent thereto producing a vibramotive force adapted to share middle- and low-frequency portions for energization of said cone type acoustic radiator.
An electroacoustic piezoelectric transducer comprises a concave diaphragm and at least two planar bimorph elements having different respective resonance frequency characteristics coupled to the diaphragm. The bimorph elements may comprise larger and smaller bimorph elements providing frequency responses in lower and higher frequency ranges respectively, and are preferably directly connected to the inner concave surface of the diaphragm.
