One aspect of this study involves a comparison of the behavior of subjective tinnitus (tinnitus for which no acoustical correlates can be measured in the ear canal) for various psychoacoustic procedures (e.g. pitch and loudness matching, masking) with the behavior of external stimuli which approximate the estimated frequency and level of the subjective tinnitus, in the same subjects. The long-term goals of this aspect of the study are: 1) to determine the degree to which subjective tinnitus behaves like an external stimulus; 2) to correlate the results of these psychoacoustic procedures with the etiology with which the tinnitus is associated, and 3) to make some determination of the level of origin of subjective tinnitus. The results of this aspect of the study will be particularly relevant to the current symptomatic treatment of tinnitus with tinnitus maskers. The other aspect of the study involves a comparison of the behavior of objective tinnitus (tinnitus for which an apparent acoustical correlate can be measured in the ear canal) for various psychoacoustic procedures with changes in the acoustical correlate [i.e. an otoacoustic emission, (OAE)] due to the same parametric variations. In addition to long-term goals analogous to those mentioned above, detailed studies of the pitch behavior of OAE's, and their effect on the pitch of external tones, may provide information relevant to the question of how pitch is coded by the auditory system.