Hiroyuki Takewa

Speaker system with image projection screen

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.

Apparatus and method for controlling tone quality

A digital signal represents a desired amplitude frequency characteristic. A desired transmission characteristic is derived from the desired amplitude frequency characteristic. A sound signal is processed in accordance with the desired transmission characteristic. The processed sound signal is converted by a speaker into corresponding sound. The process of the sound signal corrects and compensates for the original sound pressure frequency characteristic of the speaker and thereby actualizes the desired amplitude frequency characteristic.

A High Fidelity Small-sized Loudspeaker

Although bass sound reproduction through a small-sized loudspeaker requires large diaphragm displacement, the conventional supporting system cannot vibrate at an amplitude large enough for high-quality bass sound reproduction. A new supporting system is proposed which solves the problem of the conventional supporting system and focuses on the high excursion supporting system in terms of structure and displacement mechanism, in comparison with the conventional system. Using the supporting system with improved amplitude linearity and a driving system with a high force factor, a small-sized loudspeaker 8 cm in diameter has been developed. Despite the small diameter, this loudspeaker provides a large diaphragm displacement of /spl plusmn/8 mm, and therefore has superior bass sound reproduction characteristics.

Method of manufacturing a speaker diaphragm

A multi-layer block to be developed into a disk having a honeycomb construction is initially developed into a columnar block, and then the bottom of the columnar block is radially developed for obtaining a core of a speaker diaphragm. A suitable circular thin layer is attached to the top and bottom of the core to complete a diaphragm. The columnar block may be developed by means of a cone-shaped tool into a truncated cone, and this truncated cone may be further developed into a flat disk by applying a force to the top thereof. Since the forces on development are applied to the block uniformly, the density of hexagonal sections of the honeycomb construction is uniform throughout the entire circumference of the core providing superior speaker characteristics.