Tuning is accomplished by twisting the “tuning pins” ever so slightly until the string tension is correct to produce the desired “tone”. If a piano has not been tuned in several years, it will require having the “pitch raised” in order to be tuned correctly. “Standard pitch” is “A440”. This means that the “A” above “middle C” produces sound waves at the rate of 440 per second. Everything else is tuned to that note. After not being tuned for a few years, it takes drastic changes in the strings to return them to the appropriate tension. Because the strings are so close together, a drastic change in tension affects the strings next to the one you are tuning. After the drastic changes are made to all the strings, you must “re-tune” the piano, making only subtle changes to the tension of the strings. Sometimes if it has been 15 or more years, the “pitch” may be so low that it may take 3 tunings to reach “A440”. After a piano has not been tuned for many years, when the pitch is raised, and it is tuned; it will not hold that tuning for very long. The piano literally goes into shock. Because the structure is not used to having that much pressure on it, it will settle. After a few months you should have your piano tuned again. That tuning should last a year or two.
A piano’s tone contains a slight reverb effect. This is due to variations in string length. These variations must be compensated for when you tune the piano. This is called a piano’s “temperament”. Electronic keyboards have attempted to duplicate this effect for many years. Although, to this point they have not. Some very expensive keyboards can sound close, however, no keyboard can exactly match the distinctive tone of an acoustic piano. The age of electronics has also brought us electronic tuners or Strobe Tuners. For guitars, violins, cellos, etc., these work fine. Even pianos can be “rough tuned” (raising the pitch). However, because electronic tuners cannot compensate for string length variations to fine tune a piano, an accurate temperament must be achieved the same way as it has for over 100 years: tuning “by ear” by an experienced, qualified piano tuner.
When you tune a piano “by ear”, the first thing that you do is called “setting a temperament.” This means exactly what it says; you take a center octave and adjust it. Starting with one note, you tune “4ths” (expanding slightly) and “5ths”(contracting slightly) moving back and forth until every note in the “octave” has been tuned. The expansions and contractions are necessary to compensate for the imperfection of the piano. The amount of variations between “4ths” and “5ths” are determined by trial and error until all chords harmonize properly. Whatever these variations end up being is considered the “temperament” of the piano. After accomplishing this, you adjust each string from that “octave” to both the treble and bass ends of the “string scale”. You tune octaves to each other (F sharp to F sharp, G to G, etc.). Most notes have 3 strings. Each must be tuned together. This is called a “unison”. “Unisons” and “octaves” are tuned by adjusting string tension until all “overtones” are eliminated.
The simple mechanics of tuning can be learned in a day. However, it can take many years to develop the concentration and “the ear” to be accurate. Also you must develop “hand and ear” coordination. “Hand and eye” coordination is something you use all day, everyday, in everything you do. However, “hand and ear” coordination is something you never use. In the 1930’s, Don Conder began learning how to tune pianos at the Governor Morehead School for the Blind in Raleigh, North Carolina. Piano tuning is a profession in which blind people actually have a head start because they have already started developing “hand and ear” coordination out of necessity. They used to teach piano tuning in many schools for the blind. You may have noticed that many older piano tuners are blind. However, as more and more blind children are being mainstreamed into regular schools, not as many are learning to tune pianos. Piano tuning is becoming a lost art.