Possible Clues:

• A team captain who knows the score?
• Musical conductor ... and what the end of 18-, 23-, 40- or 51-Across can be?
• Music director
• Count Basie, notably
• Conductor, perhaps, excluded songs in audition
• One who must face the music?
• Baton waver
• Ricky Ricardo was one
• Musical director also featured in British editorial
• Miller, say, stopped songs being heard