An eyeglass frame and electroacoustic device combination for the improvement of natural hearing has temples that contain or carry electronic and electroacoustic devices. To enable persons with reduced hearing to again be able to follow a conversation in noisy surroundings, e.g. to concentrate on a partner during a cocktail party situation, to clearly understand speech in reverberant rooms, to concentrate on sound from a specific direction, to enjoy again theater and concert performances, each temple of the eyeglass frame comprises, directly at its front end, a directional microphone. The direction of maximum sensitivity extends to the front of the wearer, and its direction of minimal sensitivity faces toward the electroacoustic transducer at the rear end of the temple, near the ear of the wearer. This electroacoustic transducer is arranged at the rear end of the temple on an arm of a temple. In the position of use, the transducer is applied gently against only parts of the auricle, possibly also with the interposition of a foam member, which must be acoustically fully transparent. This provides access for the natural sound from the users surrounding to the auditory meatus. This direct and undistorted access is necessary for the buildup of pinna transfer functions which help perceive the directional information of the sound source(s).
Directional hearing in noisy environments is enhanced using small conventional microphones. In one embodiment a conventional first order bidirectional gradient microphone is employed in connection with a barrier to produce sound shadow at the rearward end of the microphone. In other embodiments such as hearing assistive devices worn on a person's head or body, the head or body of that person serves as the barrier. The result is a significant reduction in gain for all frequencies of acoustic energy emanating from generally rearward of the microphone. The sound shadow creates an apparent change of direction of arrival for rearwardly arriving acoustic energy, thereby making it appear to the microphone that the sound is approaching from the high attenuation 90.degree. direction. Two spaced bidirectional microphones worn on a person's body may be positioned to take advantage of this effect while simulating binaural hearing in an assistive listening device. A similar directional result is obtained with two conventional cardioid microphones mounted on a common casing to face in opposite directions. Electronic circuitry subtracts the output signal of the rearward facing microphone from the output signal of the forward facing microphone to render the combination highly directional. Case noise and other mechanical vibrations modulating the two output signals are nulled out in the subtraction process.
The present invention increases the aperture size of a microphone array by introducing a diffracting structure into the interior of a microphone array. The diffracting structure within the array modifies both the amplitude and phase of the acoustic signal reaching the microphones. The diffracting structure increases acoustic shadowing along with the signal's travel time around the structure. The diffracting structure in the array effectively increases the aperture size of the array and thereby increases the directivity of the array. Constructing the surface of the diffracting structure such that surface waves can form over the surface further increases the travel time and modifies the amplitude of the acoustical signal thereby allowing a larger effective aperture for the array.
The present invention increases the aperture size of a microphone array by introducing a diffracting structure into the interior of a microphone array. The diffracting structure within the array modifies both the amplitude and phase of the acoustic signal reaching the microphones. The diffracting structure increases acoustic shadowing along with the signal's travel time around the structure. The diffracting structure in the array effectively increases the aperture size of the array and thereby increases the directivity of the array. Constructing the surface of the diffracting structure such that surface waves can form over the surface further increases the travel time and modifies the amplitude of the acoustical signal thereby allowing a larger effective aperture for the array.
This invention relates to a hearing enhancement system having an ear device for each of the wearer's ears, each ear device has a sound transducer, or microphone, and a sound reproducer, or speaker, and associated electronics for the microphone and speaker. Further, the electronic enhancement of the audio signals is performed at a remote digital signal processor (DSP) likely located in a body pack worn somewhere on the body by the user. There is a down-link from each ear device to the (DSP) and an up-link from the DSP to each ear device. The DSP digitally interactively processes the audio signals for each ear based on both of the audio signals received from each ear device. In other words, the enhancement of the audio signal for the left ear is based on the both the right and left audio signals received by the DSP. In addition digital filters implemented at the DSP have a linear phase response so that time relationships at different frequencies are preserved. The digital filters have a magnitude and phase response to compensate for phase distortions due to analog filters in the signal path and due to the resonances and nulls of the ear canal.
Headphones with two receivers, which can be inserted, each preferably surrounded by a foam pad, into the two auricles of the user and fixed with a hoop, and the hoop, which fixes the two receivers in the auricles of the user, is formed by spectacles, the two receivers being fixed to the free ends of the side pieces and the free ends of the side pieces running essentially in a straight line to the center of the auricles.
