What is a Pitch Raise?
Technicians use many different terms for this process: Double or Triple Tuning, Tension Adjustment and Pitch Raise all mean the same thing, and that is this:
Your piano is designed to sound its best when tuned to A-440 (when the A above middle C vibrates 440 times per second). When your piano varies from A-440, pitch adjustments are required to bring it back to standard.
If a piano has gone without tuning for an extended period, its pitch may have dropped far below A-440.