This invention relates to a system (100) and method for synthesizing an audio input signal of a hearing device. The system (100) comprises a microphone unit (102) for converting the audio input signal to an electric signal, a filter unit (110) for removing a selected frequency band of the electric signal and pass a filtered signal, a synthesizer unit (118) for synthesizing the selected frequency band of the electric signal based on the filtered signal thereby generating a synthesized signal, a combiner unit (120) for combining the filtered signal and the synthesized signal so as to generate a combined signal, and finally an output unit (122, 124, 126) for converting the combined signal to an audio output signal.