Band and choral preservice teachers (N = 44) studied band and choral scores, listened to recordings of school ensembles, and identified errors in the recordings. Results indicated that preservice teachers identified significantly more errors when listening to recordings of their primary area (band majors listening to band, p = .045; choral majors listening to chorus, p = .012). Furthermore, band majors identified rhythm errors more frequently than pitch errors when listening to both types of ensembles, while chorus majors listened predominantly for pitch errors. A significant correlation existed between choral majors' ability to detect pitch errors in choral recordings and their ability to detect pitch errors in band recordings (r = .556). Theory course grades were not significantly correlated to error detection abilities, but aural skills course grades were related to ability to identify pitch errors outside the primary area (band majors, r = .441; choral majors, r = .611).A music teacher's ability to detect errors in ensemble performance is a critical skill for effective rehearsing and teaching. Cavitt (2003) found that almost 50% of band rehearsal time was spent on error correction, even as repertoire approached performance dates. Given the many kinds of possible errors (e.g., pitch, intonation, diction, and dynamics), compounded with classroom management demands, it is understandable that preservice teachers have difficulty identifying errors in the rehearsals they