Automated smartphone-based threshold audiometry has the potential to provide affordable audiometric services in underserved contexts where adequate resources and infrastructure are lacking. This study investigated the validity of the threshold version (hearTest) of the hearScreen™ smartphone-based application using inexpensive smartphones (Android OS) and calibrated supra-aural headphones. A repeated-measures, within-subject, study design was employed, comparing automated smartphone audiometry air conduction thresholds (0.5 to 8 kHz) to conventional audiometry thresholds. A total of 95 participants, with varying degrees of hearing sensitivity, were included in the study. 30 participants were adults, with known bilateral hearing losses of varying degrees (mean age of 59 years, 21.8 SD; 56.7% female). 65 participants were adolescents (mean age of 16.5 years, 1.2 SD; 70.8% female), of which 61 had normal hearing and 4 had mild hearing losses. Within the adult sample, 70.6% of thresholds obtained through smartphone and conventional audiometry corresponded within 5 dB. There was no significant difference between smartphone (6.75 min average, 1.5 SD) and conventional audiometry test duration (6.65 min average, 2.5 SD). Within the adolescent sample, 84.7% of audiometry thresholds obtained at 0.5, 2 and 4 kHz corresponded within 5 dB. At 1 kHz 79.3% of the thresholds differed by 10 dB or less. There was a significant difference (p&#060.01) between smartphone (7.09 min, 1.2 SD) and conventional audiometry test duration (3.23 min, 0.6 SD). The hearTest application using calibrated supra-aural headphones provided valid air conduction hearing thresholds. Therefore, it is evident that using inexpensive smartphones with calibrated headphones provides a cost-effective way to provide access to threshold air conduction audiometry. / Dissertation (M Communication Pathology)--University of Pretoria, 2016. / Speech-Language Pathology and Audiology / M Communication Pathology / Unrestricted