The purpose of this study was to investigate relationships of teaching effectiveness, ensemble performance quality, and selected rehearsal procedures to various measures of intrarehearsal achievement (i.e., musical improvement exhibited by an ensemble during the course of a single rehearsal). Twenty-nine high school bands were observed in two rehearsals of a common music selection. Separate panels of experts evaluated ensemble performance quality from audio recordings and teacher effectiveness from video recordings. Rehearsal frames were identified in second-day rehearsals, and "before" and "after" rehearsal trials for each target ("N" = 404) were extracted and evaluated for achievement. Selected rehearsal procedures within each frame also were measured. Results indicated no significant relationships between rehearsal effectiveness scores and any of five conceptualizations of intrarehearsal achievement. Significant, positive correlations were found between performance quality and three achievement computations, and between performance quality and rehearsal effectiveness. With one exception, none of the selected rehearsal procedures were associated with achievement differences within rehearsal frames. These findings suggest limitations of considering ensemble teacher evaluation in terms of student achievement. An ensemble's extant skill level may contribute more to short-term rehearsal achievement than does the quality of its conductor's rehearsing.