Abstract: The speaker disclosed in this invention comprises: (a) a central cap fixed on voice coil bobbin; (b) a shaft fixed in the center of the central cap; and (c) a bearing filled with lubricating fluid and fixed in a through-hole disposed in the center of a magnetic circuit. The speaker has excellent characteristics without sliding noise or harmful rolling phenomena but with reduced harmonic distortion due to the introduction of a magnetic fluid or a lubricant used as a lubricating fluid.

Abstract: A microphone includes a diaphragm for receiving a sound pressure, a back plate disposed parallel to the diaphragm, a support for holding the diaphragm and the back plate with a fixed gap in between, and a mechanoelectric transducer coupled to the back plate. These items are housed in a case, and a hole is provided on the side of the case that is not directly opposite the diaphragm. By making the volume of the confined space small by using the diaphragm as the boundary surface, mechanical resistance can be increased, and sensitivity to an excessive sound pressure can be reduced thus enabling suppression of generation of distortion.

Abstract: In a sound reproducing apparatus, a target control value is determined automatically from a noise and a sound radiated from a loudspeaker unit, and a volume of a reproduced sound is naturally compensated according to an amount of the noise against a masking due to a noise at a listening point. A first microphone is located near a loudspeaker box, and a second microphone is located in the loudspeaker box. A gain of s variable gain amplifier is changed so that an integrated value of a signal obtained by filtering and adding the outputs of the microphone may be equal to an integrated value of the filtered signal of the output of the variable gain amplifier.

Abstract: A microphone includes a diaphragm for receiving a sound pressure, a back plate disposed parallel to the diaphragm, a support for holding the diaphragm and the back plate with a fixed gap in between, and a mechanoelectric transducer coupled to the back plate. These items are housed in a case, and a hole is provided on the side of the case that is not directly opposite the diaphragm. By making the volume of the confined space small by using the diaphragm as the boundary surface, mechanical resistance can be increased, and sensitivity to an excessive sound pressure can be reduced thus enabling suppression of generation of distortion.

Abstract: In a sound reproducing apparatus, a target control value is determined automatically from a noise and a sound radiated from a loudspeaker unit, and a volume of a reproduced sound is naturally compensated according to an amount of the noise against a masking due to a noise at a listening point. A first microphone is located near a loudspeaker box, and a second microphone is located in the loudspeaker box. A gain of s variable gain amplifier is changed so that an integrated value of a signal obtained by filtering and adding the outputs of the microphone may be equal to an integrated value of the filtered signal of the output of the variable gain amplifier.

Abstract: The speaker disclosed in this invention comprises: (a) a central cap fixed on voice coil bobbin; (b) a shaft fixed in the center of the central cap; and (c) a bearing filled with lubricating fluid and fixed in a through-hole disposed in the center of a magnetic circuit. The speaker has excellent characteristics without sliding noise or harmful rolling phenomena but with reduced harmonic distortion due to the introduction of a magnetic fluid or a lubricant used as a lubricating fluid.

Abstract: A speaker having a voice coil bobbin wound around with the voice coil and a detection coil together. The detection coil is formed by a wire whose diameter is smaller than one fourth of that of the wire used for the voice coil, and wound in a space among the voice coil wires. In another example, the voice coil and the detection coil are formed using a flat type wire. In a speaker made in accordance with the present invention, the outer diameter of the whole coil structure containing a voice coil and a detection coil does not increase; as a result, decrement of the magnetic flux density in magnetic gap does not occur. Thus, the signals that proportionately represent the speaker vibration are made available without inviting deterioration in the efficiency of a speaker, nor an increased Q0.

Abstract: A signal produced by a speaker is removed from a totaled sound of noise around the speaker and the signal from the speaker, thereby extracting correctly the noise around. This structure allows an audio reproducing apparatus of the present invention to masking compensation more naturally. This audio reproducing apparatus includes a detecting coil (17) disposed on a bobbin (16) of the speaker (13), and a microphone (15) disposed around the speaker (13). An output signal from the detecting coil (17) and an output signal from the microphone (15) are respectively filtered, and then undergo an adding process. An input signal is adjusted its magnitude based on these processed signals.

Abstract: An audio reproducing apparatus is utilized in noisy environment in which noise level greatly varies. The apparatus includes first and second microphones placed respectively inside and outside a speaker box. Outputs of respective microphones are filtered, and then added with each other so that signals proportional to outside noise can be extracted. A gain of variable gain circuit can be changed with these extracted signals, whereby sound can be reproduced in noisy environments.

Abstract: The object of the present invention is to offer an sound reproduction apparatus equipped with a speaker having a drastically improved acoustic characteristics securing a stable and high S/N ratio over a wide frequency range. In order to accomplish these objects, the inputted audio signal is amplified by a power amplifier and is reproduced in an acoustic output by driving a speaker, and the reproduced acoustic output is detected by a microphone disposed in a closed cabinet together with said speaker and the detected signal is amplified by a microphone amplifier and is processed by a filter. Then, the output signal from said filter and the input signal to said power amplifier are added and processed, and the difference signal between the added signal and said inputted audio signal is used as an input signal to said power amplifier constituting a negative feedback circuit accomplishing the objects of this invention.

Abstract: An acceleration sensor includes a case having a bottom part, a pair of opposed walls substantially perpendicular to the bottom part, and a pair of first projections located on the bottom part. The sensor further includes a detection section attached to the case via the pair of first projections for detecting an acceleration and outputting a signal indicating the acceleration, and a spacer located on the bottom part of the case. In addition, the sensor includes an amplifier circuit board attached to the case in the state of being opposed to the detection section with the spacer interposed therebetween and having an amplifier on a substrate thereof for amplifying the signal output by the detection section. Relay terminals are provided for electrically connecting the detection section and the amplifier circuit board, together with output terminals electrically connected to the amplifier circuit board for supplying the amplified signal to an external circuit.

Abstract: A starter with a gear reduction mechanism including an internal ring gear formed of synthetic resin and a reinforcing member. The internal ring gear has a cylindrical portion and a toothed portion formed on an inner peripheral surface of the cylindrical portion. The reinforcing member is secured around an outer surface of the cylindrical portion.

Abstract: A planetary gear starter with a molded synthetic resin ring gear supported by a frame is disclosed. The ring gear has longitudinally-extending ribs formed in its outer surface which confront longitudinally-extending inward projections formed in the inner surface of the frame. A cylindrical elastic member has an annular portion which is press fit over the ring gear and longitudinally-extending projections which fit into the cavities formed between adjacent ribs and inward projections in the frame. The projections of the elastic member serve as shock absorbers and elastically transmit torque from the ring gear to the frame. The elastic member has an annular portion which reinforces the open end of the ring gear.

Abstract: In a waterproof device for an electric motor having a cylindrical motor frame body which is split into a discrete portions in the axial direction of the motor, an annular elastic member is attached onto the motor frame body in a manner to cover the joined portions of the split frame body, and a lead-out portion having an insertion port is formed in the elastic member to enable a power supply lead wire for the electric motor to be pushed into the insertion port.