Matsushita Electric Industrial Co., Ltd.

Tadashi Tamura

Yasutoshi Nakama

Hiroyuki Hashimoto

Kenichi Terai

Kazue Sato

Shuji Saiki

Akihisa Kawamura

Akira Kurozuka

Masaharu Matsumoto

Satoshi Takayama

Hiroyuki Takewa

Katsuji Hattori

Shuichi Obata

Toshihiko Date

Tsuneo Tanaka

Katsuaki Satoh

Toshio Nakamura

Michiko Ogawa

Kosaku Murata

Youichi Kimura

Mituhiko Serikawa

Naomi Kimura

Susumu Urata

A sound field controller of the invention reproduces a sound field which provides a distance perspective depending on a position of a sound image for a listener. The sound field controller includes: an A/D converter; a signal processing section for processing the digital signal using predetermined parameters, and generating a sound signal; an input device for inputting conditions which include a position of a sound image to be localized and a distance from a listener; a parameter controller for setting the parameters in the signal processing section so that the sound signal has characteristics in accordance with the input conditions; a D/A converter; and a reproducing unit for amplifying and reproducing the signal output from the D/A converter.

Sound field controller and control method

The noise control system of this invention includes: a noise detector for detecting a noise generated from a noise source in order to output a noise detection signal; an adaptive filter portion for outputting a control signal based on the noise detection signal so as to cancel the noise; a control loudspeaker for receiving the control signal that is to radiate a control sound to a predetermined region; and an error detector for detecting a residual error of the noise and the control sound in the predetermined region, wherein the adaptive filter portion includes: an adaptive filter for receiving the noise detection signal and processing the noise detection signal to output a control signal; an IIR filter section for receiving the noise detection signal, performing a filtering process to the noise detection signal according to a predetermined frequency characteristic, and outputting a first processing signal; an operation section for receiving the first processing signal, performing convolution with the first processing signal and a predetermined transfer function, and outputting a second processing signal; and a multiplying section for receiving the second processing signal and the error signal, multiplying the second processing signal by the error signal, and outputting an update signal for updating coefficients of the adaptive filter to the adaptive filter, the predetermined frequency characteristic and the predetermined transfer function being determined based on a control transfer characteristic from the control loudspeaker to the error detector.

Noise control system and method

An active noise controller includes a prediction filter which includes a delayer for delaying the noise or error detection signal by a predetermined period of time, a first adaptive filter for processing the output of the delayer to deliver its periodic component, and a subtractor for subtracting the output of the first adaptive filter from the noise detection signal to deliver a random component of the signal. More specifically, the prediction filter is capable of dividing the noise or error detection signal into two, periodic and random, components. In addition, two, second and third, adaptive filters are provided for processing the periodic and random components respectively. Accordingly, the second and third adaptive filters become responsive precisely to their respective periodic and random components regardless of the ratio in level between the two components, whereby any undesired noise consisting of the two discrete components will be suppressed.

Noise controller

A speaker system has an acoustic diaphragm and an image projection screen provided on a surface of the diaphragm integrally therewith so as to enable the user to enjoy both realistic image on the screen and powerful sound reproduced through the diaphragm. The rear surface of the diaphragm is closed at a peripheral portion thereof while the central portion of the rear surface of the diaphragm is opened to the exterior, so that the speaker system can provide a high level of reproduced sound pressure in low-pitched region, while the thickness of the speaker is reduced remarkably. The diaphgram can be driven by a plurality of driving units so that the speaker system can operate only with an ordinary stereophonic amplifier. The diaphragm can be composed of a pair of diaphragm elements capable of vibrating independently of each other and the screen may be integrally and commonly attached to the surfaces of these diaphragm elements in such a manner as to allow the diaphragm elements to vibrate independently of each other, whereby the speaker system can operate in stereophonic mode. Any variation in the acoustic characteristic attributable to variation in the condition of installation is compensated for by a change in the ratio of the opened area of the rear surface of the diaphragm to the whole effective vibration area or by a selective provision of a sound absorbing member on the rear side of the cabinet.

Speaker system with image projection screen

A speaker system which has a speaker unit with a diaphragm and an acoustic path provided on the front side of the diaphragm so as to guide sound waves emitted from the diaphragm. The acoustic path is defined by a sound absorbing member. The space in the acoustic path and the sound absorbing member is separated by a partition member which is disposed in such a manner that at least a portion of the sound absorbing member is exposed to the space in the acoustic path, except that the portion of the sound absorbing member just adjacent the diaphragm is not exposed to the acoustic path. This arrangement eliminates peaks and troughs of resonance determined by the length of the acoustic path, so that flat sound pressure frequency characteristics can be obtained over a wide range up to high-pitch tone region.

Speaker system

Electric coffee maker

Growing community of inventors

Toyonaka, Japan

Tadashi Tamura