Abstract: A programmable patient controlled master hearing aid is disclosed which consists of a hearing aid test module, an operator's console and a patient's console, both of which are microprocessor based, and all of which are interconnected to provide a testing apparatus which is used by the patient to select electronic components to be imployed in a hearing aid. The testing device has selectable electronic components that match the components which will be used in the hearing aid which the patient selects as best assisting or addressing the patient's hearing loss. The patient is located in the center of a sound field created by multiple speakers which accurately reproduce both pre-recorded environmental background sounds and pre-recorded or live "target-stimuli" such as speech. Thus surrounded by a simulation of real-world listening situations, the patient initially selects a hearing aid shell assembly which comfortably fits in the patient's ear.