Abstract: An attenuator is disclosed that enables a microphone's relatively undistorted pick up of a voice that is generated in close proximity to the microphone. This attenuator is a key component of a groundbreaking assistive device or handset/headset that empowers individuals with speech impairments to effectively communicate and reintegrate into society. By leveraging advanced acoustic hardware, intelligent voice algorithms, and a comprehensive image-or-vocabulary-to-impaired-voice database, the handset/headset facilitates understanding the user's impaired speech by harvesting understood terminology and outputting the same in a communicative context. Thus, the handset/headset enables seamless public interaction, independence, and improved quality of life to the user with speech impediments and ensures equal participation and inclusion in everyday verbal interactions.

Abstract: The acoustic attenuator also serves as a protective microphone enclosure that reduces exposure to debris as well as environmental humidity 5 and harmful gases.

Abstract: Disclosed is a precisely controlled microphone acoustic attenuator that lowers the sound pressure level to minimize microphone distortion. The acoustic attenuator also serves as a protective microphone enclosure that reduces exposure to debris as well as environmental humidity and harmful gases.

Abstract: A head-gear mounted bone-conducting microphone includes a housing attachable to a helmet and a transducer housed in a flexible shroud. The shroud is attached to the housing. A resilient material is disposed within the shroud. A void is provided between the resilient material and the housing to prevent the transducer from transmitting vibrations directly from the housing to the transducer. This configuration allows the microphone to effectively mechanically isolate the minuscule vibrations associated with speech from the enormous vibrations associated with most loud environments (machinery, equipment, transportation, aircraft, tanks, construction, sporting events, etc.).

Abstract: The present invention relates to dual-diaphragm electroacoustic transducers wherein a common magnetic flux path comprises first and second magnetic gaps and a magnet assembly. The invention may provide a miniature transducer with a compact magnetic flux path of improved performance. Electroacoustic transducers in accordance with the invention may comprise a small number of separate parts and provide good acoustic conversion efficiency in a miniature or compact housing.

Abstract: A feed forward technique is used to provide active noise reduction within an ear canal blocked with a passive noise reducing apparatus such as an earplug. Sound outside the ear is monitored and converted into an electronic signal that is opposite in phase from the anticipated sound leakage in the ear canal. The electronic signal is converted back into sound and fed forward into the ear to provide a cancellation effect with the actual sound leakage.

Abstract: A JFET preamplifier for use with a high impedance transducer, having an inherently capacitive input bias impedance. The capacitance of the input bias impedance is effectively neutralized by capacitively coupling the JFET gate bias circuit to the source electrode of the JFET. The JFET preamplifier is configured as a source follower which reduces any capacitance between the JFET gate and source electrode by the open loop gain of the amplifier. By capacitively coupling the JFET gate bias circuit capacitance to the JFET source electrode, the overall input capacitance of the preamplifier stage is reduced.

Abstract: A preamplifier for use with high impedance audio frequency transducers, having two capacitance coupled stages each including a field effect transistor connected in follower mode. The two stages provide an impedance converter. The first field effect transistor is of substantially smaller geometry than the second, providing a low noise, low input capacitance. The second stage further reduces output impedance while maintaining low power supply feedthrough. A capacitor connected in shunt between the stages is employed for frequency shaping.

Abstract: A housing and diaphragm assembly for use in an acoustic transducer comprises a performed face plate having a ring shaped ridge for mounting the diaphragm. The housing includes a tubular sleeve having one end received over the ridge and secured to the face plate. Additional elements comprising an electret transducer are mounted with the diaphragm on the ridge internally of the housing.

Abstract: An in-the-ear electroacoustic transducer is constructed to limit the effect of accretion of cerumen on acoustically active surfaces: to prevent cerumen from plugging passages for acoustical energy to the tympanic membrane and to facilitate the removal of cerumen from the transducer by the user. A casing has a hollow tubular wall, and diaphragm means is mounted to the casing near one end thereof, the casing being shaped for insertion in the ear to define a space generally bounded by the ear canal, the tympanic membrane and the diaphragm means. The diaphragm means has a flexible film surround, and stop means are provided to limit its movement inwardly of the casing. The transducer can be incorporated in or utilized as various hearing aids respectively adapted for different depths of insertion within the ear canal.

Abstract: An audio frequency amplification circuit for use with low level, high impedance signal sources, such as a miniature electret microphone, particularly useful where the power supply range is variable or may be limited to a single cell. The preferred embodiments of the circuit include a field effect transistor preamplifier stage operating as a voltage follower which is biased by a first and second impedance network coupled to the gate electrode of the FET transistor. A first impedance network is coupled between the power source terminals to provide a floating bias point. A second, high impedance network comprising (in one embodiment) a pair of parallel, reverse oriented diodes and a high impedance resistor is coupled between the bias point and the gate terminal of the transistor. In a further embodiment, the first impedance network comprises series connected high impedance resistors, and the second impedance network includes only the parallel, reverse oriented diodes.

Abstract: An amplifier having improved input impedance and reduced susceptibility to power supply ripple, particularly suited for use with a high impedance signal source, utilizes at least two field-effect transistors; the signal source is connected to the gate of the first FET, which is connected to a reference potential by a high resistance, whereas the source electrode of the first FET is connected to the reference potential (usually ground) through a much smaller load resistance and is also connected to the gate of the second FET. The source of the second FET is connected to the drain of the first FET and the drain of the second FET is connected to a power source, usually a low voltage source.

Abstract: A high frequency emphasis microphone particularly adapted to a hearing aid application provides a steeply rising frequency response characteristic relative to frequency, and has a low pass sonic attenuator for providing to the undriven side of the microphone diaphragm a sonic counterpressure which at low frequencies substantially cancels ambient sound pressure delivered to the driven side of the diaphragm, the attenuator reducing this counterpressure at elevated frequencies to provide accentuated high frequency response. The attenuator includes a pair of inertance-forming restricted passageways passing a portion of incoming sound to a bypass port leading to the undriven side of the diaphragm, the passageways being defined by a U-shaped plate disposed within a chamber confronting the driven side of the diaphragm.

Abstract: A stepped frequency microphone particularly adapted to a hearing aid application provides a stepped frequency response characteristic relative to frequency, and has a low-pass sonic attenuator for providing to the undriven side of the microphone diaphragm a sonic counterpressure which at low frequencies substantially cancels ambient sound pressure delivered to the drive side of the diaphragm, the attenuator reducing this counterpressure at elevated frequencies to provide accentuated high frequency response.

Abstract: An acoustic transducer with an improved electret assembly mounting for providing spacings between the fixed and movable electrodes, and having as one feature the lowering of the undesired capacitance therebetween.

Abstract: An acoustic transducer with an improved electret assembly mounting for providing spacings between the fixed and movable electrodes, and having as one feature the lowering of the undesired capacitance therebetween.