Most musicians can tune their own instruments, but with a piano, it requires the services of a highly trained and experienced technician. It is because high tensions are involved, the sheer number of strings, and the complex nature of the instrument are combine.
Tuning is the adjustment of its individual string’s tension so that they vibrate at the frequencies that give the correct pitch. A piano is a fixed-pitch instrument, which means the tuning interval cannot be changed through the player’s technique as they can with wind, brass, and unfretted stringed instruments.
Since the 1850s, pianos has been tuned in equal temperament, a tuning system that ensures every interval played within any key will sound in harmony. This in effect means that all intervals within an octave are tuned fractionally sharp or flat so that the overall effect sounds pleasing.
The octaves in the middle register of the piano are then tuned pure, gradually being stretched in the top treble and flatter in the extreme bass. This helps to balance the ends of the piano, as the higher harmonics heard in the bass strings sound much sharper than the actual notes in the upper register.
So the piano tuner’s job is actually to mistune a piano in order that all keys sound pleasing . There are two possible ways to pursue this. Most experienced tuners use a tuning fork (invented by John Shore in 1712) to set either C40 (middle C) or A37 to the correct pitch and then work empirically by ear to equalize the rest of the piano.
Some, however, use an electrical device that gives the desired pitch for each note. Whichever system is used, this is only half the job. Probably the toughest area of skill to master is in stabilizing a piano’s tuning, so that the strings do not shift their position once finely set.
It is awe-inspiring to think that there are something like 220 strings on a piano. Each one holding up to 200 pounds (90kg) of tension, running over two bridges and rubbing against sidegraft pins. Also, there is the twisting and bending opportunities within the pin block itself; and that it only needs one to slip a fraction to destroy a piano’s sound.
To master piano tuning, it takes a great amount of patience, time, and good instruction. Most technicians are trained at a college or in a workshop for four years before gaining the basic competence. Finding a good tuner is essential for a piano’s potential.
It is always best to have a recommendation from a trusted source. Most countries now have recognized trade bodies whose members have to pass a stringent test, like the Piano Technicians Guild in the U.S. or the Piano Tuners Association in the U.K.
All pianos need tuning periodically and the frequency depends on the severity of climatic change, age and condition of the instrument, and how it is used. It is important to keep a piano regularly tuned, because its pitch will dropflat when neglected. And it may take several tunings to achieve stability at the correct pitch.
For anybody starting piano lessons, particularly children, it is essential to develop not only the finger coordination to press the right notes but also the ear to recognize pitch and the tone colors of the piano.
To keep a domestic instrument tuned to concert pitch and to maintain a degree of stability requires a minimum of two tunings a year. Pianos with new strings may need more, as these strings need to stretch out much of their elasticity before they become stable enough to hold a constant tension.
A teacher’s piano should be tuned more often, because it will receive much more varied use than a practice piano. Also, it will aid a student’s ability to recognize the pitch and the tone. Concert and studio pianos are tuned before each use; this can be twice a day. A technician may be held on call unit the session has finished, in case something goes wrong with the piano.