Patent ID: 8218802

Claim:
A method for an occlusion reduction in an acoustic appliance, comprising: processing an audio signal in a transmission path of the acoustic appliance by a signal processing unit; emitting the processed audio signal as an acoustic signal by an output transducer; detecting a sound signal by an auditory channel microphone; supplying the sound signal to a loop filter arranged in a feedback loop of an occlusion reduction unit; injecting an output signal of the loop filter into the transmission path; observing a transfer function in the acoustic appliance, wherein the observing of the transfer function comprises observing changes in the transducer transfer function; and readjusting the loop filter based on a change in the observed transfer function for optimizing the occlusion reduction, wherein the processed audio signal passes through a compensation filter before being combined with the output signal from the loop filter, wherein the compensation filter is readjusted based on the change in the observed transfer function for optimizing the occlusion reduction, and wherein the output signal from the loop filter is injected into the transmission path between the compensation filter and the output transducer, and wherein the transfer function from the input of the output transducer to the output from the auditory channel microphone is determined based on the input signal to the output transducer and an output signal from the compensation filter, wherein the input signal to the output transducer and the output signal from the compensation filter are evaluated for determining a filter coefficient of the loop filter and the compensation filter, and wherein a determination of said transfer function based on the input signal to the output transducer and the output signal from the compensation filter is not performed when an occlusion signal is present.