Yamaha Corporation

Yupo Corporation

Tomoya Miyata

Yu Tsuchihashi

Hiroshi Koike

Seiichiro Iida

Kunio Hiyama

Hidekazu Kodama

Asumi Matsuda

Kazuyuki Kobayashi

Takayuki Nose

A composition for an acoustic member includes a non-diene butyl rubber, and a liquid polymer having a molecular weight of 1,000 to 120,000. A difference in an SP value between the liquid polymer and the butyl rubber is within ±0.5.

Composition for acoustic member and acoustic member

Provided is a measurement method including measuring, by using a piezoelectric sheet sensor in contact with a measurement object, vibration transmitted from the measurement object to the piezoelectric sheet sensor and measuring pressing force between the measurement object and the piezoelectric sheet sensor.

Measurement method and measurement apparatus

An electroacoustic transducer includes a housing, one or more partition walls, a diaphragm, and a tube. The one or more partition walls divide an inner space of the housing into a plurality of spaces, such that a volume of a first of the plurality of spaces is different from a volume of a second of the plurality of spaces except the first of the plurality of spaces. The diaphragm is disposed in the housing, such that one surface thereof faces the plurality of spaces. The tube establishes communication between a sound wave emission opening that is open to an outer space of the housing and each of the plurality of spaces.

Electroacoustic transducer

A electroacoustic transducer includes a housing, a piezoelectric element, a partition wall, a first tube, and a second tube. The piezoelectric element is disposed in the housing and includes a porous film and a pair of electrodes that sandwich the porous film therebetween. The partition wall divides an inner space of the housing into a first space closer to one of the pair of electrodes, and a second space closer to another of the pair of electrodes. The first tube establishes communication between a sound wave emission opening that is open to an outer space of the housing and the first space. The second tube establishes communication between the sound wave emission opening and the second space.

A sensor unit capable of protecting a piezoelectric element and detecting vibration and sound is provided. The sensor unit comprises a sheet-like piezoelectric element having a porous layer, and a sound propagation sheet covering at least one face of the piezoelectric element and permitting transmission of sound from a first face toward a second face of the sound propagation sheet. A difference in acoustic pressure level between the sound incident on the sound propagation sheet and the transmitted sound is preferably no greater than 10 dB. A surface density of the sound propagation sheet is preferably from 0.03 g/mto 100 g/m. The sound propagation sheet is preferably flexible and preferably has voids. The sensor unit preferably further comprises a sound insulation sheet covering another face of the piezoelectric element and substantially preventing transmission of sound from a second face toward a first face of the sound insulation sheet.

Sensor unit and musical instrument

A transducer includes a hollow housing, and a piezoelectric sheet which is disposed on a first portion of an inner wall of the housing, and a block which is disposed on a second portion of the inner wall of the housing.

Transducer

The board for a musical instrument according to the present disclosure includes: a first base layer; and a pair of first reinforcement layers laminated on both face sides of the first base layer, in which the first reinforcement layers includes a fiber and a binder, and the fiber is a polyparaphenylenebenzobisoxazole fiber, a liquid crystal polyester fiber, an aramid fiber, a polyarylate fiber, an ultra high-molecular weight polyethylene fiber, a polyethylene naphthalate fiber or a glass fiber.

Board for musical instrument, and stringed instrument

A cellulose fiber can reduce environmental burden while providing an enhanced modulus of elasticity easily and reliably. A composite material contains the cellulose fiber. A method of producing the cellulose fiber includes preparing a solution where needle-shaped phases each comprising a cellulose I crystal structure are dispersed in a matrix phase comprising a cellulose II crystal structure. The cellulose fiber includes the matrix phase and the needle-shaped phases contained in the matrix phase and the needle-shaped phases are oriented along an axial direction.

Cellulose fiber, composite material, and method of producing the cellulose fiber

An electronic percussion pad includes: a pad main body that is formed of a foaming elastomer; and a composite layer that includes an expandable fiber sheet laminated on a front surface of the pad main body. In the composite layer, fiber of the fiber sheet and a foaming elastomer of the pad main body are present, and the composite layer contains bubbles.

Method of manufacturing electronic percussion pad

An electronic percussion pad includes a pad layer and a holding layer that holds this pad layer from a back surface thereof, in which the pad layer is formed of polyurethane foam laminated on a front surface of the holding layer. This pad layer is directly bonded to the holding layer by allowing a polyurethane foam composition, which is supplied to one surface of the holding layer, to foam and be cured.

Growing community of inventors

Hamamatsu, Japan

Tomoya Miyata