Abstract: Certain embodiments of a noise canceling microphone with acoustically tuned ports are disclosed herein. In one aspect of the invention, the noise canceling microphone may comprise a housing, a transducer for converting received energy received into electrical signals, where the transducer is located in the housing, a front and rear sound pathways to a front and rear sound openings in the transducer, where the front and rear sound pathways may be located on opposite sides of the housing and may be displaced 180 degrees off a vertical axis. The noise canceling microphone may further comprising a boom for supporting the noise canceling microphone, where the boom may be deformed to place the noise canceling microphone near the mouth of the user. For example, the boom may be deformed to place the noise canceling microphone at least ten millimeters away from the edge of the mouth of the user.

Abstract: A directional microphone assembly suitable for subsurface mounting. A directional pickup pattern is developed from the outputs of a plurality of omnidirectional microphone elements mounted in an assembly behind a surface such that their acoustic excitation comes from the opposite side of the surface through small openings in the surface. The openings may have varying dimensions and may be covered with acoustically semi-transparent material without significantly degrading the assembly frequency response or polar pattern. Precautions are taken to ensure design robustness considering practical microphone element characteristics and potential high levels of low-frequency excitation.

Abstract: A hearing aid apparatus is disclosed that employs both an omnidirectional microphone and at least one directional microphone of at least the first order. The electrical signals output from the directional microphone are supplied to an equalization amplifier which at least partially equalizes the amplitude of the low frequency electrical signal components of the electrical signal with the amplitude of the mid and high frequency electrical signal components of the electrical signals of the directional microphone. A switching circuit accepts the signals output from both the omnidirectional microphone and the directional microphone. The switching circuit connects the signal from the omnidirectional microphone to an input of a hearing aid amplifier when the switching circuit is in a first switching state, and connects the output of the equalization circuit to the hearing aid amplifier input when the switching circuit is in a second switching state.

Abstract: A hearing improvement device using a multi-coil coupling system and methods for operating such a device are disclosed. An embodiment of the present invention may use an array microphone to provide highly directional reception. The received audio signal may be filtered, amplified, and converted into a magnetic field for coupling to the telecoil in a conventional hearing aid. Multiple transmit inductors may be used to effectively couple to both in-the-ear and behind-the-ear type hearing aids, and an additional embodiment is disclosed which may be used with an earphone, for users not requiring a hearing aid.

Abstract: A hearing test device and method are disclosed which involve the placement of a testing probe in the ear canal of a test subject. The device analyzes responses to stimuli applied to the ear canal to determine whether the testing probe has been properly placed in the ear canal. The device may determine, for example, whether the probe is stable, whether it is sealed in the ear canal, whether the resulting volume of the ear canal is acceptable, and/or whether the stimuli delivery system is blocked in any way. If the device determines that the testing probe has been properly placed in the ear canal, the device automatically starts a hearing test without requiring any operator input.

Abstract: An improved analog-to-digital converter device suitable for use in digital hearing aids, and methods for operating such a device are disclosed. Aspects of the present invention may provide a full 16–18 bits (96–108 dB) of dynamic range in a digital hearing aid circuit using 14-bit analog-to-digital converters typically available for hearing aid use. An embodiment of the present invention may use two analog-to-digital converters that are clocked by the same sampling trigger. One of the converters may be preceded by an amplifier having, for example, 24 dB of gain, while the other converter may be preceded by an amplifier having 0 dB of gain. The output of the first converter or the output of the second converter may be used, or a combination of the two outputs may be used to produce audio for the hearing aid user, depending upon input signal level.

Abstract: An improved insert earphone for audiometric testing is provided, having a housing, a receiver located within the housing, a flexible eartip located externally to the housing, and a tube nipple acoustically coupled between the receiver and the flexible eartip. The flexible eartip has a flexible tube portion that is coupled to an output end of the tube nipple, which may be rigid. The housing and tube nipple are configured and arranged such that the angle between a longitudinal axis of the tube nipple and the vertical axis is obtuse, minimizing the stress on the ear canal when the flexible eartip is inserted therein. An acoustic damper may be located at or near the input end of the tube nipple to prevent ear wax from clogging the damper and minimize the need for damper replacement.

Abstract: A microphone assembly generally for hearing aid and communications applications is disclosed. The microphone assembly operates in both directional and non-directional or omni-directional modes. The microphone assembly has front and rear sound inlet tubes, and an actuator switch that may be moved between a first position in which the rear tube is plugged, defining the omni-directional mode, and a second position in which the rear tube is unplugged, defining the directional mode. Circuitry senses the position of the actuator switch and selects a microphone output based on the position sensed.

Abstract: An acoustic resistor or damper and method of manufacturing the same is disclosed. The damper has mesh material and mounting material attached to the mesh material. The mounting material defines an open region for transmission of sound through the mesh material, and has a mounting surface for mounting the damper on a surface surrounding an acoustic port or tube. The mounting surface is located on a plane different from the mesh material, thereby shielding the mesh material from adhesive applied between the mounting surface and the surface surrounding the acoustic port or tube. The method of manufacturing an acoustic damper comprises exposing emulsion applied to a mesh material through at least one opening in a photographic mask to ultraviolet light and removing the emulsion exposed. A portion of the remaining emulsion and mesh material is cut in a shape surrounding the removed emulsion.

Abstract: A microphone capsule for an in-the-ear hearing aid is disclosed. The capsule can include a top plate having first and second spaced openings defining front and rear sound inlets, and a directional microphone cartridge enclosing a diaphragm. The diaphragm is oriented generally perpendicular to the top plate and divides the directional microphone cartridge housing into a front chamber and a rear chamber. A front sound passage communicates between the front sound inlet and the front chamber, and a rear sound passage communicates between the rear sound inlet and the rear chamber. Front and rear acoustic damping resistors are associated with the front and rear sound passages. The acoustic resistor pair provides a selected time delay, such as about 4 microseconds, between the front and rear sound passages. The use of two acoustic resistors instead of one levels the frequency response, compared to the frequency response provided by a rear acoustic damping resistor alone.

Abstract: A directional microphone assembly for a hearing aid is disclosed. The hearing aid has one or more microphone cartridge(s), and first and second sound passages. Inlets to the sound passages, or the sound passages themselves, are spaced apart such that the shortest distance between them is less than or approximately equal to the length of the microphone cartridge(s). A sound duct and at least one surface of a microphone cartridge may form each sound passage, where the sound duct is mounted with the microphone cartridge. Alternatively, each sound duct may be formed as an integral part of a microphone cartridge.

Abstract: An improved hearing aid is disclosed having a switched release automatic gain control. In one embodiment, an input signal is presented to a comparator with a reference typically around, for example, 65 dB SPL instantaneous. The output of the comparator controls a switch in a release circuit of an automatic gain control. While the instantaneous input level exceeds the threshold, the release circuit is enabled and the automatic gain control behaves normally. While the instantaneous input level does not exceed the threshold, the release circuit is disabled and the automatic gain control maintains its current gain setting, essentially indefinitely. Because speech, even soft speech, has a very high positive peak content, this circuit will recover any needed gain in the presence of speech (assuming an appropriate threshold) but not recover gain to background noise whose positive peak content is below the threshold.

Abstract: A low battery detection circuit is disclosed for detecting low battery voltages in hearing aids and other battery operated devices. The low battery detection circuit operates reliably on a small amount of current, which does not significantly increase overall battery drain. An output signal is generated whose amplitude and frequency increase as battery voltage decreases below a predetermined level. The circuit's minimal number of components and output signal characteristics make it particularly applicable as a low battery early warning device for hearing aid devices.

Abstract: A hearing aid assembly having a directional microphone mounted externally to a hearing aid body is disclosed. The hearing aid, which may be, for example, an in-the-canal (ITC) or completely-in-the-canal (CIC) hearing aid, has a mounting arm attached to an external surface of the hearing aid body, and the mounting arm in turn has a directional microphone mounted therewith. The mounting arm provides mechanical and electrical connection between the directional microphone and the hearing aid. The mounting arm is also configured such that, upon insertion of the ITC or CIC hearing aid into the ear canal of a wearer, the microphone is located in the region above the tragion portion of the ear.

Abstract: A hearing screener apparatus is provided. In one embodiment, the hearing screener comprises a housing, a testing probe and one or microphones mounted with the testing probe. An elastic coupler may be used to suspend the testing probe from the housing. The testing probe may include a shaft and a removable probe tip mounted on the shaft. An ear tip is fitted onto an end of the removable probe tip. The ear tip may have a flexible flange arranged at its end to seal within the ear canal of the patient. The screener allows the testing probe to be manipulated about all axes and may have an isolation body or assembly that acts as the elastic coupler. The elastic coupler provides vibrational noise isolation due to movement of the patient and the user.

Abstract: A hearing aid system for selecting one of two audio sources is disclosed. The hearing aid system comprises hearing aid circuitry, such as, for example, a hearing aid amplifier and speaker, as well as a primary source for audio, such as, for example, a hearing aid microphone. The hearing aid system also comprises a secondary source for audio, such as, for example, a directional microphone worn or otherwise supported by a person speaking or by the hearing aid user, as well as detection and switch circuitry to select which of the primary and secondary audio sources should be directed to the hearing aid circuitry. In operation, the detection and switch circuitry receives a signal transmission (preferably wireless) from the secondary audio source and determines whether the signal received is desirable. If the signal transmission is desirable, the circuitry selects that signal for coupling with the hearing aid circuitry.

Abstract: An acoustic resistor or damper and method of manufacturing the same is disclosed. The damper has mesh material and mounting material attached to the mesh material. The mounting material defines an open region for transmission of sound through the mesh material, and has a mounting surface for mounting the damper on a surface surrounding an acoustic port or tube. The mounting surface is located on a plane different from the mesh material, thereby shielding the mesh material from adhesive applied between the mounting surface and the surface surrounding the acoustic port or tube.

Abstract: A hearing aid system is disclosed that enables a two-wire configuration for power, data and ground, and two-way communication between a hearing aid and an external programming device or system. In one embodiment, the hearing aid includes a receiver and a bypass capacitor, such as commonly found with Class D receivers. Circuitry is included that switches between a normal hearing aid operating mode in which the bypass capacitor is connected, and a programming mode in which at least the bypass capacitor is disconnected. Switching may occur in response to the input voltage of the hearing aid rising above and falling below a predetermined threshold. The hearing aid may operate using three different voltages, one for normal operation and two others representative of logic signals during the programming mode.

Abstract: An insert earphone is provided in which a piece of foam material is used to resiliently mount a receiver within a chamber portion of a one-piece plastic housing member. The receiver has an output port extending through a central aperture of the piece of foam material and into one end of a passage defined by a tubular portion of the housing member with a damper being disposed in the other end of the passage. The tubular portion is inserted into an ear tip or other coupling device and has an enlarged diameter end section to achieve a locking action. Two such insert earphones may be coupled through cables to a junction unit and filters are provided for enhancing the drive of the earphones at high frequencies, the filters being preferably mounted in the junction unit.