Patent ID: 8116489

Claim:
An electro-acoustic system including: an electro-acoustic circuit including a negative-feedback loop, the negative feedback loop comprising of: a microphone for generating an internal signal from an acoustical signal located within or closely coupled to an occluded or partially occluded ear; a second electronic circuit (B) for modifying the internal signal to produce a processed internal signal; a combiner for combining the processed internal signal with a processed external signal to produce a combined signal; a first electronic circuit (A) for modifying the combined signal to produce a receiver signal; and a receiver for generating an acoustical signal from the receiver signal at a location within or closely coupled to the occluded or partially occluded ear; the electro-acoustic circuit further comprising of: a third electronic circuit (C) for modifying an external signal to produce the processed external signal; and a fourth electronic circuit (D) for estimating the level of the receiver signal either directly from the receiver signal or from the combined signal and producing a control signal from this estimate; wherein the processing performed by the second electronic circuit (B) is controlled by the control signal.