Abstract: The invention refers to a programmable signal processing device mainly intended for hearing aids and of the kind which include an electronically controlled signal processor. Hearing aids for persons having impaired hearing are normally adjusted for only one frequency response and are adapted to amplify the frequencies which the patient has difficulties to hear. At different sound environments as for example conversations with disturbing background sounds, normal conversation in quiet environments or at lectures, the conditions of listening are different. Up to now this problem has not been solved satisfactorily for hearing aids. With the present invention a number of different signal processes, can easily be selected to suit different sound situations automatically or by the user himself.