United States of America As Represented by the Secretary of the Air Force

Other

USA As Represented by Secretary of the Navy

The United States of America As Represented by the Secretary of

Douglas S Brungart

Griffin D Romigh

Brian D Simpson

William M Rabinowitz

Benjamin M Sheffield

Dianne K Popik

Victor S Finomore, Jr

The present application describes a plurality of test simulation environment mimic complex listening environment of everyday life, comprising a speech component, and a noise component. The application also describes an auditory testing system and method for evaluating a listener's speech perception and method to test hearing prosthesis or hearing protection device's effect on a person's speech perception in a complex listening environment.

System and method for evaluating speech perception in complex listening environments

A method of analyzing performance of frequency lowering hearing aids. The method includes generating a sequentially of noise signals and transmitting acoustical sounds from a sound output device in response to the sequence of noise signals. A sound input device records the acoustical sounds and saves as a first device data. The sound input device with a frequency lowering hearing aid records the acoustical sounds and save as a second device data. The second device data is compared to the first device data and, in response to the comparison, at least one function of the frequency lowering hearing aid is optionally adjusted.

Method and apparatus for analyzing and visualizing the performance of frequency lowering hearing aids

A multi-modal communications system integrates multiple different communications channels and modalities into a single user interface that enables operators to monitor and respond to multiple audio and text communications.

Multi-modal communications (MMC)

A method of enhancing vertical polar localization of a head related transfer (HRTF). The method includes splitting an audio signal and generating left and right output signals by determining a log lateral component of the respective frequency-dependent audio gain that is equal to a median log frequency-dependent audio gain for all audio signals of that channel having a desired perceived source location. A vertical magnitude of the respective audio signal is enhanced by determining a log vertical component of the respective frequency-dependent audio gain that is equal to a product of a first enhancement factor and a different between the respective frequency-dependent audio gain at the desired perceived source location and the lateral magnitude of respective audio signal. The output signals are time delayed according to an interaural time.

Methods of using head related transfer function (HRTF) enhancement for improved vertical-polar localization in spatial audio systems

A spatial audio system for implementing a head-related transfer function (HRTF). A first stage implements a lateral HRTF that reproduces the median frequency response for a sound source located at a particular lateral distance from a listener, and second stage implements a vertical HRTF that reproduces the spectral changes when the vertical distance of a sound source changes relative to the listener. The system improves the vertical localization accuracy provided by an arbitrary measured HRTF by introducing an enhancement factor into the second processing stage. The enhancement factor increases the spectral differentiation between simulated sound sources located at different positions within the same 'cone of confusion.'

Head related transfer function (HRTF) enhancement for improved vertical-polar localization in spatial audio systems

The present invention provides a means for two or more remotely-located individuals to communicate information about the spatial coordinates of a location of mutual interest in a more rapid, robust, and intuitive manner than is possible with any current voice communication system.

Remote auditory spatial communication aid

A computationally efficient method and device for adding spatial audio capabilities to new and existing centrally switched communication systems without modifying the internal operation of the systems or the switching architecture by producing a digitally filtered copy of each input signal to represent a contralateral-ear signal with each desired talker location and treating each of a listener's ears as separate end users.

Efficient spatial separation of speech signals

An auditory attitude indicator for aircraft that includes an audio source providing an audible signal, a' stereo headset with a left side and a right side, an aircraft avionics system that provides at least aircraft pitch data and roll data to an audio processor unit. The audio processor unit includes at least one lookup table of coefficients corresponding to a plurality of possible aircraft pitch and roll orientations and at least two selectable multipoint finite impulse response filters. The first selectable multipoint finite impulse response filter having a first coefficient selected by the audio processing unit from the lookup table based upon the aircraft pitch data and roll data for varying the audible signal to the stereo headset left side. The second selectable multipoint impulse response filter for varying the audible signal to the stereo headset right side having a second coefficient selected by the audio processing unit from the lookup table based upon the aircraft pitch data and roll data.

Auditory attitude indicator with pilot-selected audio signals

Optimal head related transfer function spatial configurations designed to maximize speech intelligibility in multi-talker speech displays by spatially separating competing speech channels combined with a method of normalizing the relative levels of the different talkers in a multi-talker speech display that improves overall performance even in conventional multi-talker spatial configurations.

Spatial processor for enhanced performance in multi-talker speech displays

Device and method for controlling the perceived distances of sound sources by manipulating vocal effort and presentation level of a synthetic voice. Key components are a means of producing speech signals at different levels of vocal effort, a processor capable of selecting the appropriate level of vocal effort to produce a speech signal, and a carefully calibrated audio system capable of accurately matching the RMS power of the signals reaching the listener's left and right eardrums to the power that would occur for a sound source 1 m directly in front of the listener in an anechoic environment.

Speech-based auditory distance display

System and method for actively canceling the acoustic noise generated by changes in the electric current within the gradient coils of a magnetic resonance imager based on the finding that the acoustic noise in the magnetic resonance imager is highly periodic but that the period of the magnetic resonance imager noise changes substantially during a scan. The acoustic noise signal is measured at the ears of a patient undergoing a magnetic resonance imaging, delayed by a variable number of samples and the resulting signal is subtracted from the acoustic noise signal. Magnetic resonance imaging noise cancellation occurs at the level of 20 decibels or more.

Delay based active noise cancellation for magnetic resonance imaging

A computer controlled, three-dimensional, iterative and reiterative, closed-loop system for automatically positioning the head of a manikin situated on a motorized stand relative to a stationary sound source in order to perform accurate near-field Head-Related Transfer Function (HRTF) measurements. The positioning is based on acoustic signals measured from microphones located at each ear of the manikin and is accomplished with three-axis precision for accurate near-field HRTF measuring.

Manikin positioning for acoustic measuring

Acoustic point source transducer apparatus including a high-output acoustic sound source propagating sound through a long, flexible tubing having an open end with a small diameter. Sound radiates from the small diameter open end effectively acting as an acoustic point source. A flexible sleeve encasing the terminal end of the tubing permits convenient wand-like placement of the acoustic point source by a human operator and an electromagnetic position sensor at the small diameter open end determines point source position. The invention provides a convenient, nondirectional approximated acoustic point source for improved acoustic measuring, especially desirable for near-field Head-Related Transfer Function measuring.

Acoustic point source

A simplified, low-cost analog system for displacing the perceived source of a stereophonic studio signal from an inherent location within the listener's head to selected fixed alternate locations such as thirty degrees on either side of and a few feet in front of the listener. The disclosed system employs selected analog filters including ear canal resonance-simulating pinna related filters and signal delaying multiple poled Bessel filters to displace the apparent sound source to the predetermined external locations. The audio filter elements are preferably implemented with operational amplifiers with the pinna related filter enhancing frequencies around 5 KHz, and with the output of the pinna related filter being sent directly to one audio channel, and the output of the delay filter is sent to the other channel. Two signal channels can be processed simultaneously using a symmetrical circuit for the other input channel and mixing together the outputs. Both use of pinna related filtering in each channel of the system and dual benefit use of a Bessel function based delay are believed notable aspects of the invention.

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Rockville, MD, United States of America

Douglas S Brungart