Abstract: A piezoelectric acoustic transducer achieves both space-saving and high sound quality without increasing the number of parts. In order to achieve this, the transducer 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. 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. 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: A sound field measuring device uses a measurement signal which has at least one change point and whose frequency spectrum has a shape corresponding to a shape of a frequency spectrum of a background noise. This enables a sound field measurement, which is for measuring an impulse response or transfer function of a sound field space which is a linear time-invariant system to be measured, to be performed with a high S/N ratio over a wide frequency band.

Abstract: A wide frequency range signal from a test sound source is reproduced successively by a plurality of speakers, and the reproduced sound is detected by a plurality of microphones, after which the frequency characteristics are obtained at FFTs, while obtaining the frequency characteristics of the wide frequency range signal at an FFT. A high frequency range level is normalized with a low frequency range level, and a determination section compares the normalized value with a reference value stored in a reference value storage section to determine the number and positions of people in the sound field. The transfer functions between the speakers and the microphones are calculated at transfer function calculators, and impulse responses are obtained at IFFTs, after which a reverberation time calculator calculates the reverberation time based on the impulse responses. An audio signal is adjusted based on the results.

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: A sound field measuring device according to the present invention uses a measurement signal which has at least one change point and whose frequency spectrum has a shape corresponding to a shape of a frequency spectrum of a background noise. This enables a sound field measurement, which is for measuring an impulse response or transfer function of a sound field space which is a linear time-invariant system to be measured, to be performed with a high S/N ratio over a wide frequency band.

Abstract: A speaker system for a picture receiver provides for lessening of the casing width of the picture receiver while assuring highly uniform acoustic characteristic at listening points in a sufficiently broad range. The speaker system for picture receiver and its speaker installing method comprises a first speaker for reproducing medium and high range sound at the right and left of the screen of a picture receiver and a second speaker for reproducing medium and low range sound under the screen, wherein the speaker system is set in such place that when a listening point is set at a position a first distance apart from the picture receiver and within a second distance from the front axis at the center of the right and left of the screen, the distance from the first speaker to the listening point is R1, the distance from the second speaker to the listening point is R2, and the crossover frequency is f, then R1, R2 and f satisfy the specified relative formula.

Abstract: A speaker system for a picture receiver provides for lessening of the casing width of the picture receiver while assuring highly uniform acoustic characteristic at listening points in a sufficiently broad range. The speaker system for picture receiver and its speaker installing method comprises a first speaker for reproducing medium and high range sound at the right and left of the screen of a picture receiver and a second speaker for reproducing medium and low range sound under the screen, wherein the speaker system is set in such place that when a listening point is set at a position a first distance apart from the picture receiver and within a second distance from the front axis at the center of the right and left of the screen, the distance from the first speaker to the listening point is R1, the distance from the second speaker to the listening point is R2, and the crossover frequency is f, then R1, R2 and f satisfy the specified relative formula.

Abstract: A wide frequency range signal from a test sound source 1 is reproduced successively by a plurality of speakers 101 to 104, and the reproduced sound is detected by a plurality of microphones 111 and 112, after which the frequency characteristics thereof are obtained at FFTs 4b and 4c, while obtaining the frequency characteristics of the wide frequency range signal at an FFT 4a. A high frequency range level is normalized with a low frequency range level, and a determination section 8 compares the normalized value with a reference value stored in a reference value storage section 9 to determine the number and positions of people in the sound field. At the same time, the transfer functions between the speakers and the microphones are calculated at transfer function calculators 10a and 10b, and impulse responses are obtained at IFFTs 12a and 12b, after which a reverberation time calculator 13 calculates the reverberation time based on the impulse responses.

Abstract: A piezoelectric loudspeaker includes: a piezoelectric vibrator including a diaphragm and a piezoelectric member provided on at least one face of the diaphragm, the diaphragm being vibrated by the piezoelectric member; a frame for supporting the piezoelectric vibrator; and a visco-elastic member provided on at least one face of the piezoelectric vibrator. The visco-elastic member is disposed in a substantial center of the piezoelectric vibrator. The visco-elastic member has a bottom face area which accounts for about 11% to about 80% of a bottom face area of the diaphragm.

Abstract: A damper 3A is provided with an inner peripheral waveform portion 11 and an outer peripheral waveform portion 12. A flat portion 10 is provided between the inner peripheral waveform portion 11 and the outer peripheral waveform portion 12. When the damper is used for a loudspeaker, the flat portion 10 does not elastically deform in a radial direction R, so that linearity of the damper 3A in a vibrating direction Z is ensured by elastic deformation of the waveform portions. In addition, a rolling phenomenon of a voice coil bobbin and a diaphragm can be suppressed.

Abstract: A damper 3A is provided with an inner peripheral waveform portion 11 and an outer peripheral waveform portion 12. A flat portion 10 is provided between the inner peripheral waveform portion 11 and the outer peripheral waveform portion 12. When the damper is used for a loudspeaker, the flat portion 10 does not elastically deform in a radial direction R, so that linearity of the damper 3A in a vibrating direction Z is ensured by elastic deformation of the waveform portions. In addition, a rolling phenomenon of a voice coil bobbin and a diaphragm can be suppressed.

Abstract: The loudspeaker includes: a frame; a magnetic circuit portion; a diaphragm transmitting air vibration; a cylindrical voice coil bobbin connected to the diaphragm; a voice coil fixed to an outer peripheral portion of the voice coil bobbin; and a damper holding the voice coil in such a manner that the voice coil is capable of vibrating in a magnetic gap formed between an annular top plate and a center pole included in the magnetic circuit portion. The damper includes a flat portion which has a hole for passing the voice coil bobbin therethrough at its center, and a plurality of roll structures connected to a periphery of the flat portion and having a cross-section including a bent periphery. Each of the plurality of roll structures is fixed to the frame, and the hole of the flat portion is fixed to an outer peripheral surface of the voice coil bobbin.

Abstract: A speaker has a diaphragm of which plane shape as seen from a vibrating direction has a major axis and a minor axis, a band-shaped edge connected to the outer circumference of the diaphragm for holding so that the diaphragm may be free to vibrate, and a frame for holding the outer circumference of the edge, wherein a viscoelastic member is affixed to part of the edge and/or diaphragm.

Abstract: The loudspeaker of the invention includes: a frame; a diaphragm, a planar shape thereof being non-axisymmetric having a larger diameter and a smaller diameter when the diaphragm is viewed from a vibration direction thereof; a band-shaped edge portion provided around an outer periphery of the diaphragm, an outer periphery of the edge portion being connected to the frame and an inner periphery of the edge portion being connected to the diaphragm; a cylindrical voice coil bobbin in a non-axisymmetric shape having a larger diameter and a smaller diameter which includes a pair of opposed faces parallel to each other in a larger diameter direction, one end portion of the voice coil bobbin being connected to the diaphragm; a voice coil wound around the voice coil bobbin; a plurality of voice coil bobbin reinforcing members in a plate shape which are bridged between the pair of opposed faces parallel to each other of the voice coil bobbin; and a plurality of magnetic circuits having a gap for applying magnetic fluxes

Abstract: In a speaker system capable of controlling the directivity, a first pair of speaker units are disposed at a cabinet from face having vertical and horizontal axes, so that the diaphragm centers are located along a line which is parallel with the horizontal axis of the front face. A second pair of speaker units are disposed so that the diaphragm centers are located along a line which is parallel with the vertical axis of the front face. The horizontal distance between the centers of the diaphragms of the first pair of speaker units and the vertical distance between the centers of the second pair of speaker units are different from each other. The center of the line which links the diaphragm centers of the first pair of speaker units and the center of the line which links the diaphragm centers of the second pair of speaker units are located at the same position. A fifth speaker unit may be disposed on the front face of the cabinet at a center of an area surrounded by the first and second pair of speaker units.

Abstract: In a speaker system, the rearward area of a diaphragm is separated into two acoustic regions. One of the two acoustic regions is a rear opening type and the other is a base-reflex type. An acoustic mass, such as a port or a passive radiator, is located between the first and second acoustic regions for providing a phase inversion characteristic.