Transient evoked otoacoustic emissions (TEOAE) are an objective means for measuring cochlear hearing loss in newborn infants. TEOAEs are low-intensity sounds produced by the normal cochlea that are elicited by acoustic stimuli and then recorded in the outer ear canal. Protocols are being developed for clinical use, and pass/fail criteria are usually based on the size of the emission. The common practice is to wait until an emission of 6 dB is achieved before recording a positive result. Within subject, stimulus-related characteristics may influence the results. Quantifying the sources of variability can effect the analysis of the results. This study will investigate the effects of gender and ear canal volume on TEOAE size. Five male and five female young adult volunteers will serve as subjects. None of the volunteers will have a history of otologic disease or use of medication. All subjects will have normal hearing and normal middle ear function. Pure-tone audiometry and single frequency immittance testing (226 Hz probe tone) will be made. TEOAE will be measured using ILO88 hardware controlled by an IBM PC.