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R&D / Technology – B4C High Sound Quality Speaker Diaphragm

  • B4C High Sound Quality Speaker Diaphragm
B4C High Sound Quality Speaker Diaphragm

A new manufacturing method and acoustic analysis technology combine to control unwanted resonances, enabling the reproduction of sound that is more true to the original.

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Overview

A new manufacturing method and an original acoustic analysis technology have come together in the development of a B4C*1 high sound quality speaker diaphragm. Our new manufacturing method realizes the world's highest propagation velocity*2 among B4C speaker diaphragms, and our acoustic analysis technology has boosted performance. Unwanted resonances are normally unavoidable in speaker diaphragms, but the new diaphragm realizes reproduction that is more true to the original, with no resonances even in the high-frequency range.

Technology Point

The diaphragms are formed using a new atmospheric pressure ceramic sintering method

ZOOM

A new atmospheric pressure ceramic sintering method*3 developed in a joint project with Mino Ceramic Co., Ltd. and the National Institute of Advanced Industrial Science and Technology (AIST) is employed in the formation of the B4C diaphragms with high density.

Realizes high propagation velocity and an appropriate level of internal loss

ZOOM

The new manufacturing method realizes levels of propagation velocity and internal loss approaching theoretical values. At 12,700m/sec, the diaphragm achieves the world's highest propagation velocity for a B4C speaker diagram.

Optimization of diaphragm shape using original acoustic analysis technology

ZOOM

An acoustic analysis technology enabling prediction of sound dispersion and sound pressure for each frequency under study was applied in the development of the new speaker diaphragm. This enabled the realization of an optimal shape that would boost the performance of the B4C.

*1
Boron carbide. This is an ultra-hard material (second only to diamond) with a specific gravity lower than that of aluminum. Because of these qualities, it possesses a high propagation velocity. Boron carbide also displays a moderate level of internal loss similar to that of paper, making it ideal for use in high sound quality speakers.
*2
As of December 2014 (Mitsubishi Electric study).
*3
A method in which the item to be formed is baked at high temperatures without being pressurized, developed in cooperation with Mino Ceramic Co., Ltd. and the National Institute of Advanced Industrial Science and Technology (AIST).
This development was announced by the National Institute of Advanced Industrial Science and Technology (AIST) on March 13, 2008.

A novel and practical method for pressureless sintering of boron carbideOpen new window

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