Abstract: An improved active noise reduction system which has a transducer, an electro-acoustic sensing means including adjacent to the transducer, an attenuation means with electro-acoustic sensing means to attenuate selected sound frequencies, said system utilizing both feed forward control means and feedback control means comprising a heteronomous electronic controller with algorithmic transfer function and said controller being individually operable.

Abstract: An improved personal noise attenuation system which attenuates both tonal and broadband sound and which includes a spatially adjustable acousto-electric sensor and attenuation means including both feedback and feed forward components so as to provide a heteronomous attenuation and more complete active noise attenuation and the adjustable acousto-electric sensor is moved to exploit the changing physical characteristics of spatial silent zones in different noise fields.

Abstract: Active noise reduction headphones for audiometry where the earphone portion of said headphones has a cavity volume greater than 6 cc and including an acoustic-electric sensing means and an electro-acoustic transducing means which are used cooperatively and which has additional passive noise control means in the form of a circumaural seal around the ear for improving high frequency noise control performance, the headphone having a summing junction for combining the active noise reduction signal and an audiometry test signal.

Abstract: The technology of active noise reduction (ANR) is incorporated into audiometry testing in a variety of formats. Analog feedback, digital feedback, adaptive feedforward, and adaptive feedback noise control schemes are presented for use in audiometry to reduce the ambient noise heard by the test subject, allowing subject testing in higher ambient noise fields. Audiometer test signals are appropriately compensated so the test results are accurate and comply with existing calibration standards for audiometers. Existing audiometry headphone technologies are modified so that ANR can be accomplished while satisfying existing standards for audiometric testing. Embodiments are also defined for alternate headphone arrangements that may not conform to current (1997) audiometric testing standards but provide sufficient performance advantages to warrant new standards for audiometry testing in the future.

Abstract: An active noise control system for use in testing hearing using a pure tone audiometry testing procedure and employing multiple switching controllers with pre-filtering means and a switch to select any one controller to provide a predetermined one and having the ability to configure each switching controller so that the maximum threshold shift occurs for the frequency of the test tone and for modifying each test tone in accordance with a standard calibration frequency.

Abstract: An improved personal noise attenuation system which attenuates both tonal and broadband sound and which includes a spatially adjustable acousto-electric sensor and attenuation means including both feedback and feed forward components so as to provide a heteronomous attenuation and more complete active noise attenuation and the adjustable acousto-electric sensor is moved to exploit the changing physical characteristics of spatial silent zones in different noise fields.