Pitch
raising
If
your piano hasn't been tuned for say a year or more, your piano technician will
most likely recommend that the
overall pitch of the of the piano be brought up
to A440 before fine tuning.
This
overall pitch adjustment is referred to as a pitch raising or lowering. In some
cases, during high humidity seasons, the piano will tend to go sharp in pitch
overall and need to be brought down to concert pitch.