Patent ID: 8687832

Claim:
A hearing aid system, comprising: a first input transducer for converting an acoustical signal to a first electrical input signal comprising a direct or external part and an acoustical feedback part; an output transducer for generating an acoustical signal from an electrical output signal; an electrical signal path between the input transducer and the output transducer and comprising a signal processing unit including an amplifier part for enabling frequency dependent gain of an input signal, the amplifier part being on an input side of the signal path between the input transducer and the amplifier part and an output side of the signal path between the amplifier part and the output transducer; an electrical feedback cancellation path between the output side and the input side of the signal path for compensating acoustic feedback between the output transducer and the input transducer by subtracting from a signal on the input side of the amplifier part, the electrical feedback cancellation path comprising an adaptive filter for providing a variable filtering function providing an estimate of the acoustical feedback; a probe signal generator for generating a probe signal for use in characterizing an acoustical feedback path, the probe signal being fed to the adaptive filter of the electrical feedback cancellation path; and a feedback enhancer unit, providing an output signal for improving the estimate of the feedback cancellation path made by the adaptive filter, the hearing aid system being further adapted to provide a second electrical input signal from which the direct or external part of said first electrical input signal can be estimated, said second electrical input signal being connected to the feedback enhancer unit, wherein the feedback enhancer unit is configured to estimate the part of the first input transducer signal that does not originate from the probe signal from said second electrical input signal, which is substantially free from the probe signal, said estimate being subtracted from the first input transducer signal to provide the output of the feedback enhancer unit.