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. This means that each of its approximately 220 strings needs to be tightened considerably, adding tremendous additional tension to the piano's structure.
The challenge is that as each string is tightened, the tension causes the pitch of previously adjusted strings to change. The very process of "tuning" causes the already tuned strings to go "out of tune". This is why, in the case of a very out-of-tune or long-neglected piano it is impossible to make a substantial change in pitch and end up with a fine, accurate tuning in one step. Instead, a process called "pitch raising" must first be done, in which all strings are restored to their correct tension levels. Only then can the piano be accurately tuned.
In other words, accurate tuning is only possible when all strings are close enough to their proper tension that only small further changes are needed during tuning. These small changes then do not disturb the tuning of other strings.
How far from standard pitch must a piano be before a pitch raise is necessary?
Realistically, a pitch difference of a few percent can usually be accommodated successfully during tuning.
Any more than that - when a piano's pitch is noticeably different from that of other standard pitched instruments, a pitch correction procedure is necessary before tuning.
If a piano has been neglected for a very long time, it may not be possible to raise the pitch in one pass. In this case, two or more pitch-raises may be required prior to tuning. Some call this process "Triple Tuning". Each additional pitch-raise takes time; therefore there may be an additional charge.
Like your car, your piano is a major investment which deserves regular servicing to keep it working well and preserve its value. Most importantly, the well-maintained piano sounds better, plays better, and gives you and your family a wealth of musical pleasure.
The preceding article is edited from a Technical Bulletin published by the Piano Technicians Guild, Inc. It is provided on the Internet as a service to piano owners. Piano Technicians Guild is an international organization of piano technicians. Registered Piano Technicians (RPTs) are those members of PTG who have passed a series of examinations on the maintenance, repair, and tuning of pianos. For a list of Registered Technicians in your area visit our online member directory. For a copy of this or other PTG Bulletins and Pamphlets contact:
Piano Technicians Guild, Inc
4444 Forest Avenue
Kansas City, KS 66106-3750