After several years of exposure to musical instrument practice, musicians acquire a great expertise in processing auditory features like tonal pitch or timbre. Here we compared the performance of musicians and non-musicians in two timbre discrimination tasks: one using instrumental timbres, the other using voices. Both accuracy (d-prime) and reaction time measures were obtained. The results indicate that the musicians performed better than the non-musicians at both tasks. The musicians also took more time to respond at both tasks. One interpretation of this result is that the expertise musicians acquired with instrumental timbres during their training transferred to timbres of voice. The musician participants may also have used different cognitive strategies during the experiment. Higher response times found in musicians can be explained by a longer verbal-auditory memory and the use of a strategy to further process auditory features.