Abstract: An audio communication apparatus for an MRI apparatus performs unidirectional or bidirectional audio communication between a subject in a gantry provided in an examination room and an operator in a control room. An acoustic transducer for transmission and/or reception provided on the subject side is formed by a bone conduction microphone and/or speaker. The bone conduction microphone/speaker transmits a sound to or from the subject by contacting the subject directly or via a protection member, without relying on air as a transmission medium. The apparatus carries out audio transmission without being affected by noise, even in a high-noise environment. The apparatus allows the use of earplugs or sound insulation earmuffs.

Abstract: In a moving coil type stereophonic pickup cartridge, an armature is provided having first, second, and third leg portions which extend in three directions. A source of magnetic flux is disposed with only one pole thereof adjacent to the first, second and third leg portions of the armature. The magnetic circuits thus constructed, having an open return path, generate signals by changes in the magnetic flux through coils wound on the second and third leg portions due to the movement of the armature relative to the magnetic source. Variations in the design of the three leg armature and the magnetic source are disclosed. Practical embodiments of the invention include disclosure of cartridge replacement features providing convenient electrical connection between moving coils and remainder of the sound reproduction system.