Piano Technicians Glossary
Or, what do you mean when you say…?
Tuning, like just about everything else and the piano depends very much on the instrument and the player. All things being equal on an instrument there's the general pitch and then there is the temperament.
Generally a piano is designed to be tuned to the International Pitch Standard of A440 which is 440-wave cycles per second for the note, A above middle C. If you scratch the surface of that idea you'll discover a whole world of pitch standards.
Back when Handel wrote his Messiah he tuned the orchestra to A423, we know this because his tuning fork is still around and it was a very early tuning fork at that, since it had only just been invented by Handel's main trumpet player, John Shore.
Most pianos made in the last 100 years are engineered for A440, but tuning to slightly different pitch standards is not damaging to the instrument.
Tuning temperament is the way the 12 notes of the scale are distributed within an octave and almost without exception most pianos in the 21st century are tuned to Equal Temperament, which just means the pitches of the notes are equally far apart. Wasn't always that way and still isn't, as some pianists specialize in playing music from different historical periods and want to hear the music as it sounded under tuning systems of the time.
From a technicians point of view I can't recommend getting away from A440 and Equal Temperament unless you plan to keep the instrument that way. Changes in pitch and temperament can be destabilizing in the short term.
This is a situation where the piano has not been tended to for quite a few years or it's been living in an unsuitable environment. It is substantially off standard pitch and requires several tunings then and there.
It is destabilizing for the instrument, so regular care and attention is best.
Piano technicians divide the idea of Repair into two areas — Reconditioning and Rebuilding.
Most pianists can benefit from some level of reconditioning for their instrument but some pianos, while they still make music, are no longer candidates for anything other than a tuning.
If there are serious structural faults then rebuilding services are required if the instrument is to continue to make music. This sort of area requires a very clear understanding between the technician and the pianist about the value of the instrument before and after the rebuilding.
Making the mechanism's thousands of parts function as evenly and consistently as possible.
Sometimes this involves minor adjustments made during the tuning process and at no extra charge, other times it can require many hours of work. Everything happens 88 times on a piano.
This is making adjustment to the tonal quality of individual notes, again seeking evenness and consistency across the keyboard. Also, a highly subjective area of piano technology so communication is critical.