Abstract: An electro-acoustic transducer having a sound-generating diaphragm and means for driving the diaphragm in which the diaphragm is provided with perforations filled with damping material to oppose the formation of standing waves in the diaphragm. The perforations are arranged in between three and eight generally radially extending curved bands, each band being formed of a plurality of parallel rows of perforations extending along the length of the band.

Abstract: An electrodynamic type electroacoustic transducer wherein a diaphragm of a nonmagnetic and insulative material having thereon a series of conductors is disposed between a pair of magnetic circuits opposing one another through a slight clearance so that the conductors will lie in magnetic flux flowing between opposite polarity ends of at least a pair of permanent magnets in each magnetic circuit and will move in directions transverse the flux when the diaphragm is vibrated, in which the diaphragm is resiliently held in said clearance by means of an elastic support means inserted at least between the diaphragm and the respective opposing pole ends of the magnets in both circuits so as to be prevented from contacting the pole ends when vibrated.

Abstract: A disposable noise reducing hearing aid attachment is provided for covering the sound inlet of a hearing aid to reduce the amplitude of random noises such as wind noises and to prevent dirt and moisture from entering the sound inlet. The attachment includes a flexible foam pad having an aperture formed therethrough for alignment with the sound inlet. The pad is supported by a backing having a coating of adhesive for removably supporting the attachment to the hearing aid. A wool filter is associated with the pad aperture to reduce the random noise, and dirt and moisture from entering the sound inlet.