Abstract: A sound collecting system and a sound reproducing apparatus by means of which an actual audio image can be reproduced. The sound collecting system includes a plurality of microphones for producing sound signals and a plurality of position detecting apparatus for detecting locations of the microphones and/or positions of sound sources to produce position signals. The sound signals and the position signals are multiplexed by a plurality of multiplexers, and the multiplexed signals are stored into respective audio channels or different channels by a signal recording apparatus. The multiplexing may be performed by a frequency multiplexing method, a time division multiplexing method or the like. Since also position information is stored into corresponding audio channels together with acoustic sound signals, at the reproducing stage, reproduction is possible taking the positions into consideration and an actual audio image can be produced.

Abstract: An earphone device includes an acoustic tube having an inner diameter substantially identical to that of the external auditory canal has an ear mounting portion at one end and an acoustic non-reflecting portion at the outer end. An earphone unit and an internal microphone unit are mounted on the periphery of the acoustic tube adjacent each other and communicate with the interior of the acoustic tube with their respective vibration plates facing inwardly of the tube. The phase of the signal representing the external noise in the acoustic tube picked up by the internal microphone unit is reversed and combined with the audio signal fed to the earphone unit.

Abstract: A hearing aid is disclosed in which the outside sound collected by a microphone is amplified and radiated from the earphone unit so as to be conducted to the user's external auditory meatus. The auditory tube is of an inside diameter approximately equal to that of the user's external auditory meatus and has one end arranged as a section for attachment to the user's auricle and the other end arranged as a reflectionless terminal. The earphone unit is mounted on the peripheral surface of the auditory tube with the sound radiating surface facing the inside of the tube.

Abstract: An acoustic signal reproducing apparatus for reproducing acoustic signals through headphone devices is disclosed. The left channel and right channel acoustic signals are provided by a device for processing the transmission characteristics with constant transmission characteristics representing the location of an imaginary sound source relative to both of the listener's ears. The left channel and right channel acoustic signals, processed in this manner by the device for processing the transmission characteristics, are provided by an acoustic signal processing device with a level difference and a time difference consistent with changes in orientation of the user's head. In this manner, optimum binaural reproduction with respect to the imaginary sound source may be achieved.

Abstract: In a speaker which comprises a diaphragm having a vibrating portion and an annular conductive portion, a current feeding coil facing the conductive portion with a predetermined gap therebetween, and a magnetic circuit including a top plate, a magnet and a yoke plate to which the current feeding coil is attached; the diaphragm is formed so that an electrical resistance of its conductive portion is lower than an electrical resistance of its vibrating portion.

Abstract: A sound reproducing apparatus is provided formed of an acoustic tube having first and second opposite ends, and having substantially a same inside diameter as that of an external acoustic meatus of the user who is wearing the sound reproducing apparatus. A loudspeaker unit is mounted to the acoustic tube intermediate the first and second ends such that a sound radiating surface thereof is directed to one side of the acoustic tube. The acoustic tube has at its first end an auricular attachment which is received at the external acoustic meatus. A second end is formed as a non-sound-reflecting end. The sound reproducing apparatus may also be adapted to have two loudspeaker units mounted to one or more acoustic tubes, respectively, and two auricular attachment sections may be provided, one for each ear. Left and right channel acoustical signals may be respectively input to the respective first and second loudspeaker units for stereo operation.

Abstract: A dynamic loudspeaker comprises first and second device means each having a coil disposed in a magnetic gap formed in a magnetic circuit, a vibratory member driven by a first drive means, and a massive member opposingly disposed to the vibratory member and being driven by a second drive means, whereby reaction force generated by said vibratory member is substantially eliminated by reaction force of said massive member.