Abstract: A hearing aid comprises a forward path comprising a) an input transducer for converting sound (x(n), v(n)) in an environment around the hearing aid to an electric input signal (y(n)) representing said sound; b) a hearing aid processor for processing said electric input signal (y(n)), or a signal originating therefrom (e(n)), and to provide a processed signal (u(n)) based thereon; c) an output transducer for converting said processed signal (u(n)), or a signal originating therefrom (ua(n)), to acoustic stimuli presented to said eardrum of the user. The hearing aid further comprises d) a feedback control system for attenuating or cancelling feedback propagated via a feedback path (H) from an electric input signal to said output transducer to an electric output from said input transducer.

Abstract: A hearing system comprises a) a multitude of M of microphones providing M corresponding electric input signals xm(n), m=1, ..., M, and n representing time, b) a processor connected to said multitude of microphones and providing a processed signal in dependence thereof, c) an output unit for providing an output signal in dependence of said processed signal, and d) a database (?) comprising a dictionary (?pd) of previously determined acoustic transfer function vectors (ATFpd). The processor is configured A) to determine a constrained estimate of a acoustic transfer function vector (ATFpd,cur) in dependence of said M electric input signals and said dictionary (?pd), B) to determine an unconstrained estimate of a current acoustic transfer function vector (ATFuc,cur) in dependence of said M electric input signals, and C) to determine a resulting acoustic transfer function vector (ATF*) for a user of the hearing system in dependence thereof and of a confidence measure related to said electric input signals.