Abstract: A hearing aid has a sound-receiving microphone from which an incoming signal is supplied to a number of different channels, each channel being allocated to a different frequency range within a total expected range of frequencies for the incoming signal. Each channel includes a circuit for measuring the strength of the signal within the frequency range for that channel and for changing the respective strengths of the signals in the other channels by suppressing weak signal channels in favor of strong signal channels.

Abstract: A hearing aid which can be built into a frame, such as eyeglasses, to be worn by a hearing-impaired person has a first microphone arrangement having a directional reception pattern, and a second microphone arrangement for sound locating. The second microphone arrangement includes a first locating microphone disposed in the region of one ear of the hearing-impaired person, and a second locating microphone disposed in the region of the other ear. The signal from both locating microphones are mixed by a low-pass filter with the signal from the microphone arrangement having a directional reception pattern, and the output of the mixing operation is supplied in common to both ears of the hearing-impaired person.

Abstract: A directional microphone arrangement has a number of discrete microphones each having an electrical output and elements for deriving first and second electrical signals which are 180.degree. out of phase with respect to each other from the outputs of the microphones. A third signal is also derived through differentiation from one of the microphone outputs which is 90.degree. out of phase with respect to one of the first or second signals. All of the first, second and third signals are added in a summing unit, the output of the summing unit forming the output for the arrangement.