Answer: bflats

AnswerCrossword Clue
BFLATSWind ensembles usually tune to them
BFLATSA-sharps, by another name
BFLATSMusical tones.
BFLATSNotes hit by divas
BFLATSThey're a couple short of C notes
BFLATSThey're higher than A's
BFLATSA sharps