An ear piece device (10) configured for being supported in the ear and providing a microphone (17) which primarily detects only sounds originated by the user is contained within a housing (11) which is configured at one end to fit snugly at the ear canal of the user, but not to extend within the ear canal A microphone element (18) is coupled within the housing in a position such that the microphone element is separated from contact with the skull of the user by the housing This microphone element (18) is contained within a casement (25) which is mechanically and acoustically isolated from vibrations occurring within the housing

Unidirectional ear microphone and method

A method and apparatus for stereophonic reproduction uses conventional left and right stereophonic signals to energize a point source transducer in a complementary manner. The resultant interference sound pattern is interpreted by the brain of a listener to enable the listener to experience stereophonic hearing in a wide region surrounding the transducer, not just in the region of the plane of symmetry. A point source transducer may be simulated by a plurality of transducers positioned with the spacing therebetween less than a determinable maximum distance. While conventional stereophonic signals may be employed in the reproduction of sound, improved reproduction is obtained by producing the signals by recording sound with a pair of microphones arranged with the apogees of their respective field of polar response patterns facing substantially at 180° to one another.

Stereophonic reproduction method and apparatus

A microphone assembly (1700) includes one or more transducers (1702) positioned in a housing (1732). Circuitry (Fig. 8) is coupled to the transducer for outputting an electrical signal such that the microphone has a main lobe directed forwardly and attenuates signals originating from the sides and/or rear. The transducers can advantageously include multiple transducers, which, with the circuit, produce a desired sensitivity pattern. The microphone assembly can be employed in a vehicle accessory.

Vehicle accessory microphone

A differential input hearing aid with a programmable frequency response provides the hard of hearing with the capability to listen to individual conversations in the midst of high ambient background noise, and to have the frequency response of the hearing aid tailored to the individual user by programming the desired response characteristics into the hearing aid by digital signals. The audio inputs of two microphones are applied to a subtractive circuit with the balance of the inputs being controllable. Digitally controlled band pass filters with selectable band and selectable level of amplification are provided.

Differential hearing aid with programmable frequency response

A one-piece two-way voice communication earset is situated in or at the ear of the user and is operated hands-free. It includes either two separated microphones having their outputs combined or a single bidirectional microphone. In either case, the earset treats the user's voice as consisting of out-of-phase signals that are not canceled, but treats ambient noise, and any incidental feedback of sound from received voice signals, as consisting of signals more nearly in-phase that are canceled or greatly reduced in level. The microphones are preferably electret microphones. In addition, a logarithmic amplification circuit reduces residual ambient noise during non-speaking intervals. The earset includes a receiver coupled to a communication medium and a speaker coupled to the receiver for emitting sound from received voice signals primarily to the user's ear canal. A transmitter, a part of the earset also coupled to the communication medium and located outside the ear canal, houses the two microphones or the one bidirectional microphone.

Two-way communications earset

A microphone unit comprises a pair of like electroacoustic transducers each having sound-responsive elements in the form of identical diaphragms which are parallel to each other and mounted in a common housing that is open at at least one end for the reception of desired sounds in a direction perpendicular to the diaphragms. The diaphragms are spaced apart a distance no greater than one-quarter of the shortest wavelength of the range of frequencies of the noises to be cancelled; and the housing has further apertures that open into the housing in directions parallel to the planes of the diaphragms, these further apertures being disposed at least one on each side of each diaphragm and the interior ones of said further apertures being spaced apart from their associated diaphragm a distance no greater than one-eighth of the shortest wavelength of the range of frequencies of the noises to be cancelled. The noise sources and channels that the microphone may be exposed to are 1. air-borne ambient noises; 2. air-borne noises due to reflection and echoes; 3. direct vibration transmitted to the microphone housing through non-air channels by contact and/or mounting; and 4. microphony effects of the housing, that is, vibration produced by the housing due to all air-borne sources. Air-borne ambient noises, direct vibrations, and microphony noises will be cancelled by the arrangement of the transducers; while echoes, and reflections, as well as ambient noises, will be attenuated by the presence of the further apertures.

Noise cancelling microphone

Electro-acoustic transducer arrangement are disclosed in which the tendency to diaphragm distortion between the drive and suspension positions is reduced and the efficiency as well as linear characteristics are improved especially at lower frequencies. A loudspeaker arrangement has an externally electrically driven transducer and one or more additional transducers pneumatically coupled therewith. Such additional transducer or transducers can be suspended in the same chassis as the electrically driven transducer. An additional transducer can be suspended in a separate chassis in the same enclosure as the electrically driven transducer or in a separate enclosure connected by an acoustic transmission line with that containing the electrically driven transducer. A pneumatically driven diaphragm can actuate an electromechanical transducer the output of which is used to drive another transducer and/or to modify or control its own movement and/or that of the diaphragm of the electrically driven transducer. The relative sizes of the transducer diaphragms, their weights, their form, their suspension, the voice coil, size, weight and impedance, as well as the load values applied to the voice coils and the field strength of the associated magnet systems, will determine the frequency ranges handled by each of the pneumatically operated transducers. In this and various other embodiments of the invention, these factors are distinctively different among the various speakers, with the result that the frequency ranges of the various speakers will be different, although they may overlap. Thus the driven speaker may have a full frequency range, while the pneumatic one or ones may correct e.g. the bass or the top. The pneumatic speaker or speakers control the acoustical characteristics of the enclosure or cabinet, to improve efficiency at specific frequencies, which can be narrow bands or wide bands.

Saad Z. M. Gabr

Papers

Noise cancelling microphone

Current loaded pneumatically driven loudspeaker arrangements