Makoto Yamagishi

Open-air type earphone

An earphone has a housing divided by a driver unit into front and back cavities with a sound generation opening at the front thereof, a duct extending from the back cavity of the housing and having a length substantially larger than its diameter, and a casing attached to the housing and communicating with the back cavity through a pipe having a length longer than its diameter, with the resonant frequency determined by the casing and pipe being made near to the resonant frequency determined by the equivalent mass of the vibration system, that is, the diaphragm and voice coil of the driver unit, and by the compliance of the back cavity, so that the lowest resonant frequency of the earphone can be lowered while the peak that would otherwise be formed in the frequency characteristic of the earphone by the resonance between the back cavity and mass of the vibration system can be supressed for improving the high frequency characteristic.

Ear piece transducer

An ear piece transducer having a housing incorporating therein an electroacoustic transducer element, the housing being inserted into a concave portion of an auricle, and a ring member having resiliency sufficient to enable it to be attached to the outer peripheral portion of the housing, the ring member being formed so as to be thickest in one radial direction.

Stereo loudspeaker system with tweeters mounted on rotatable enlongated arms

A speaker system has a first baffle (2) supporting a first speaker unit for producing sounds in a first frequency range (low frequencies), at least one second baffle (27L), (27R) supporting a second speaker unit for producing sounds in a second frequency range which is higher than the first frequency range (middle and/or high frequencies), the second baffles (27L), (27R) being smaller than the first baffles (2). The second baffle (27L), (27R) are spaced a predetermined distance from the first baffle (2). The speaker system has a reduced baffle effect, and increases direct sounds radiated directly from the speaker units, as compared with indirect sounds radiated backwards from a baffle, thereby improving frequency characteristics in the middle frequencies and providing excellent sound image localization.

Electro-acoustic transducer and housing

An electro-acoustic transducer for a sound reproducing system includes an electro-acoustic transducer in a cabinet and a sound guide tube for conducting the sound from the transducer unit out of the cabinet. The sound guide tube has a sound radiating end with a smaller diameter than the external acoustic meatus to allow the sound radiating end to be inserted into the external auditory meatus.