Pioneer Electronic Corporation

Sumio Hagiwara

Tsunehiro Tsukagoshi

Toshikazu Yoshino

Yasuyuki Arai

Shinichi Yokozeki

Masataka Uchidoi

Keishi Saito

Hirofumi Yanagawa

Shinichi Yokozseki

Etsuro Nemoto

Kazuyoshi Kobayashi

A speaker system including a common input terminal for receiving an audio signal to be acoustically radiated; several speaker units; several digital filters connected between the common input terminal and the speaker units, and a filter coefficient for each of the digital filters. The speaker units are arranged linearly, in a matrix form or in a honeycomb form.

Speaker system and method of controlling directivity thereof

A molding composition is obtained by blending flaky graphite with a resin component comprising a mixture of a thermoplastic resin having a glass transition temperature higher than room temperature and another thermoplastic resin having a glass transition temperature lower than room temperature. The composition is kneaded and rolled into a sheet to orient the graphite flakes parallel to the surface of the sheet. The rolled sheet is then molded into an article, for example, speaker diaphragm, arm pipe and head shell, which may be optionally be carbonized or graphitized. The resulting article exhibits improved physical properties, especially high specific modulus of elasticity comparable to aluminum and beryllium as well as good internal loss comparable to paper.

Molding compositions and diaphragms, arm pipes and head shells molded

Elements for a tone-arm system such as arm pipes, head shells, cartridge bodies, and arm bases are fabricated from a kneaded mixture comprising polypropylene and flaky graphite powder. The mixture may further include polymethyl methacrylate and/or rubber-like material. Graphite flakes are preferably oriented parallel to the surface of the element. The elements show improved temperature resistance.

Tone-arm elements

Vibratory elements for use in audio equipment are fabricated from a kneaded mixture comprising polypropylene and flaky graphite powder. The kneaded mixture is rolled into a sheet in which graphite flakes are oriented parallel to the surface, and the sheet is then formed into a desired shape, for example, a dome- or cone-shaped diaphragm and a cantilever, as by vacuum forming, air-pressure forming or press molding. The mixture may further include polymethyl methacrylate and/or rubber-like material. The elements are characterized by improved temperature resistance.

Vibratory elements for audio equipment

Vibratory elements for use in audio equipment are fabricated from a kneaded mixture comprising post-chlorinated polyvinyl chloride and flaky graphite powder. The kneaded mixture is rolled into a sheet in which graphite flakes are oriented parallel to the surface and the sheet is then formed into a desird shape, for example, a dome- or cone-shaped diaphragm and a cantilever, as by vacuum forming, air-pressure forming or press molding. The mixture may further include polymethyl methacrylate and/or rubber-like material. The elements are characterized by improved temperature resistance.

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Tokorozawa, Japan

Sumio Hagiwara