A purpose‐built tinnitus synthesizer interfaced to a computer has been designed which can be used to characterize most types of subjective tinnitus. A patient is able to match his own tinnitus by making responses to simple questions using push buttons on a hand‐held box. The system can be used to determine the characteristics of tinnitus consisting of tones, random noise or combinations of these sounds; any sounds can also be pulsed synchronoulsy with a patient's pulse beat in order to match pulsatile tinnitus. It is then possible to use the frequency and loudness characteristics of tinnitus in order to determine the sitability of masking therapy for a pati