Murata Manufacturing Co., Ltd.

Rohm Co., Ltd.

Takeshi Nakamura

Takayuki Kaneko

Hiroshi Nishiyama

Yoshiaki Heinouchi

Ikuo Matsumoto

Tohru Kasanami

Keiichi Okano

Akira Mori

Yoshiko Morishita

Katsumi Fujimoto

Kenji Ando

Takao Mouri

Yutaka Murai

Yoshimasa Yamashita

Kazuhiro Ebara

Suehiro Kato

Akira Kumada

Satoshi Matsuda

Yukio Sakashita

Jiro Inoue

Nobuyuki Ishitoko

Satoru Fujishima

Yoshio Kawai

Kiyoshi Iwai

Takao Mori

Toshinori Miura

Tsutomu Okada

Kazuhiro Yoshitani

Tsuguji Kanbayashi

Yoshiki Morishita

Atushi Morikawa

Jyunichi Hashimoto

Yoshiko Kitayama

A speaker box and a speaker device that can be manufactured at low cost and that provide a sound-absorbing effect. A speaker box of a speaker device includes a baffle, four intermediate plates, and a rear plate. The baffle plate has a speaker mount hole at the center. Each intermediate plate has a hole. The intermediate plates are stacked such that they are alternately reversed or rotated so that the holes in the adjacent intermediate plates communicate with each other while the holes are shifted from with each other. A hollow space with a sound-absorbing effect is formed by the holes in the speaker box.

Speaker box and speaker device

A speaker system includes a main speaker and a subordinate speaker arranged around the main speaker. A pseudo-spherical wave is generated around the main speaker as a whole such that both speakers are vibrated in the frequency range of piston vibration and are in phase and that the propagation speed of a sound wave produced by the vibration of the subordinate speaker is preferably lower than the propagation speed of a sound wave produced by the vibration of the main speaker.

Speaker system

A speaker cabinet includes a cabinet having a side board to which a speaker driver can be fixed, a substantially cylindrical tube which is inserted into the cabinet such that a vertical line passing through the center of gravity of a horizontal plane of the cabinet coincides with the axis of the substantially cylindrical tube and which is in contact with the base board and the top board of the cabinet, and a support rod which is inserted into the substantially cylindrical tube through a through-hole formed in the base board of the cabinet and which supports the top board of the cabinet at the upper end portion of the support rod such that the cabinet undulates so as to move like a see-saw.

Speaker cabinet and speaker device

A spherical wave generating diffuser positioned in front of the sound emission side of a sound source. The diffuser comprises an inner horn and an outer horn positioned concentrically around the inner horn. The diffuser generates pseudo-spherical waves centered on the inner horn because the emission speed of the sound waves emitted from between the outer horn and the inner horn are slower than the emission speed of sound waves emitted from within the inner horn.

Diffuser and speaker using the same

A speaker has a very small size and is arranged to emit sound waves in a non-directional manner. The speaker includes a case and a speaker unit attached to a plate provided at an opening of the case. The speaker is arranged so that the speaker unit is mounted or attached to a floor or support surface such that a space formed by the case, the plate and the speaker unit is airtight and so that the back-and-forth motion of a vibrator of the speaker unit generates expansion and contraction of the case.

Speaker and speaker device

A transformer includes a bobbin having a cavity, a primary winding wound around the bobbin, and a secondary winding wound around the bobbin and magnetically coupled with the primary winding. In the transformer, at least one of the primary winding and the secondary winding is divided into at least two portions which include a portion wound at an inside region of the transformer and a portion wound at an outside region of the transformer. Also, at least a portion of the other one of the primary winding and the secondary winding is wound between said at least two portions obtained by dividing the one of the primary winding and the secondary winding, and at least a portion of the cavity of the bobbin is used as a space to dispose another member therein.

Transformer, loudspeaker device, loudspeaker network, and loudspeaker system

A speaker includes a disk-shaped base. A substantially hemispherical surface vibrator is fitted into a substantially circular groove formed in the base to be bonded therein. Terminals are attached to electrodes located on both surfaces of the vibrator. The edge portion of the vibrator is bonded with a first adhesive, and further, its circumference is bonded with a second adhesive. The first adhesive has a sufficient bonding strength between the vibrator and the base. The second adhesive has a lower elastic modulus than the first adhesive.

Speaker

A speaker system includes a speaker box and a speaker mounted thereon. A bass reflex duct is provided in the speaker box at a position corresponding to an approximate center portion of the speaker. In addition, another duct is provided around the speaker in the speaker box. The bass reflex duct is arranged inside of a duct so that the bass reflex duct and the duct overlap each other. The speaker system is arranged to efficiently direct the back pressure of a speaker to the bass reflex duct and greatly increases the sound pressure in resonance even when a compact speaker box is used.

An amplifier circuit includes an input terminal and a first amplifier. A node between the input terminal and the first amplifier is connected to a first input of a comparator circuit. A node between a second amplifier at the final stage and an output terminal is connected to a second input of the comparator circuit. The output of the comparator circuit is connected to a signal blocking circuit. The comparator circuit compares voltages of two input signals. When the output voltage of the second amplifier falls below the input voltage of the first amplifier, the signal blocking circuit is switched from an ON state to an OFF state. Thus, the second amplifier can be protected from excessive current caused by short-circuiting of the output terminal, without deteriorating the dumping factor and the transient characteristic. Even when the signal level is so low that only a minute current flows, it is possible to detect short-circuiting of the output terminal and to protect the second amplifier.

Amplifier circuit and electronic apparatus using the same

A speaker device is capable of accurately generating sound even within a high audio region, without high sound pressure even when generating a large sound. The speaker device includes a sound-producing vibrator having a vibrating body which is, for instance, a semi-spherical piezoelectric ceramic. Electrodes are provided on both surfaces of the vibrating body. An input signal from an amplifier is input between the electrodes so that the vibrating body is vibrated and sound is produced. The resonant frequency of the sound-producing vibrator is set higher than about 20 kHz, which is the upper limit of the human audible range. Furthermore, the thickness of the vibrating body is increased and its mass is increased.

Speaker device

A speaker has a semi-spherical vibration section and a ringed plate-like base section. The vibration section and the base section are formed as a single, unitary piezoelectric body. Driving electrodes are located on the single unitary body comprising the vibration section and the base section. The driving electrodes are connected with lead electrodes and the lead electrodes are connected with connecting terminals.

A method of making a speaker with a semi-spherical vibration section and a ringed plate-like base section is disclosed. The vibration section and the base section are formed as a single, unitary piezoelectric body. Driving electrodes are located on the single unitary body comprising the vibration section and the base section. The driving electrodes are connected with lead electrodes and the lead electrodes are connected with connecting terminals.

Method of making a piezoelectric speaker with a unitary body comprising a base section and dome shaped vibrating section

A speaker includes a disk-shaped base. A substantially hemispherical surface vibrator is fitted into a substantially circular groove provided in the base and bonded therein. Terminals are attached to electrodes provided on both surfaces of the vibrator. The terminals, passing through the terminal grooves provided in the base, are led out in a direction that is substantially perpendicular to the plane of the base. Further, a horn as a separate member may be attached to the outer surface side of the vibrator.

Speaker having a hemispherical vibrator

A 3D woofer drive circuit achieves miniaturization of a 3D sound system and reduces the cost thereof. The drive circuit includes two resistors arranged to synthesize an L-channel sound signal with an R-channel sound signal. Each end of a capacitor constituting part of a low pass filter and two fixed terminals of a variable resistor are respectively connected between a connection point of the resistors and a ground terminal which is a reference potential. A speaker terminal for the woofer is connected to a movable terminal of the variable resistor through a buffer amplifier.

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Nagaokakyo, Japan

Takeshi Nakamura