The overall pitch of a piano is the total overall balanced tension in the pounds-pull of all of the 230 odd strings in the instrument. For example, in a typical piano each string, (according to length thickness, tautness, and location in the scale), exerts a calculated torsional tension or pull (in pounds) on the structural unit (back, plate, and tuning-pin block). The average tension or pull per strings is approximately 170 pounds. When we multiply the average string tension by 230 odd strings, we come up with an overall strings tension of approximately 39,000 pounds, or almost 20 tons of torsional pull with in the framework of the piano. This varies slightly between different makes and models.

It must be remembered that when a piano is constructed, the basic structural parts, (piano back, cast-iron plate, and tuning -pin block) are engineered as a unit to remain at their structural best when holding up the correct overall balanced string tension. Therefore, when the correct overall pitch is lacking, parts of the piano are apt to warp, loosen, crack, spit, bulge or otherwise suffer damage. This means loss in both the value and the performance of the instrument. If the damage is great and is sustained over a long period of time (several or more years), it can render the piano worthless.

Other critically important parts of the piano , such as the soundboard, bass bridge, treble bridge, and soundboard ribbing, suffer extensive damage from loss of overall balanced string tension. For example, the average piano string (loaded with about 170 pounds of tension) also exerts a secondary force against the bridges and "crown" of the soundboard. This push amount is about 7 pounds per string. If we multiply this by 230 odd strings, we have 1600 pounds of push force against the bridges and soundboard of a piano pitched at A-440 cps. To counter balance this tremendous push force we have the crown of the board and the curved ribs exerting force in the opposite direction. When overall piano pitch is allowed to change too much, the balanced forces between the strings tan the bridge soundboard combination are upset. The results in damage to the bridges, soundboard, ribbing, and associated parts, such damage usually takes the form of warps, splits, cracks, or broken glue bonding on the bridges.

Structural damage to the piano can be minimized by keeping the proper balanced overall string tension or proper overall pitch on the piano at all times. This can be accomplished only through regular service and tuning to the pitch of A-440 cycles per second (American Standard Pitch) Piano manufacturers continue to recommend servicing your piano at least two times a year. New pianos, or pianos that have been rebuilt require more frequent service for the first one to two years. It should be apparent why piano manufacturers and dealers will only honor the warranty of a piano if the piano owners takes proper care of the instrument.

Unfortunately, many amateur tuners do not address the need to establish the correct pitch or the consequence of leaving a piano at an incorrect pitch. Such practice allows the piano pitch to sink lower and lower, until the lack of proper overall balanced string tension results in serious structural failures in the instrument. Where lack of proper care has allowed the overall pitch to sink a quarter tone, the loss in proper overall string tension is 1500 to 2500 pounds, Where overall pitch has sunk a half tone, the loss improper overall string tension is 3000 to 5000 lbs. In many older pianos that have gone without proper care for years, the loss in proper overall balanced string tension can amount to several tons.

Once the overall tension (pitch) is correct, the piano tuner can focus on the sounds that the strings make when they are struck by the piano hammers. Every note is comprised of many different frequencies or partials which we hear as a "single" note. The technician must focus on each of these partials when tuning the instrument, adjusting the sound or number of string vibrations of each note to bring all 230 odd strings into an exact relationship. He is dealing in infinitesimal differences in sound and variations in strings vibration which are very difficult for the untrained ear to detect. Your piano tuner has switched from mechanical engineer to artist. He is conceiving beauty in sound waves in relation to the human ear. He will adjust and listen intently to the sounds of every string. In so doing he will be engaged in adjusting and making comparisons in piano string tensions, but only in infinitely small fractions of an ounce per string, and only as a byproduct of the exact sound that he must achieve. When he has finished tuning he will have 230 odd fundamental tones, each with its quota of lesser tones (partials) so arranged in harmonious relationship with one another within the framework of eighty-eight notes that only the presence of a pianist is needed to open the doors to the joys of music.

A piano will only sound its best when tuned to the correct pitch. While it may sound "in tune with itself" at other pitches, it does not sound the same. As string tension changes, the relationship of partials does not stay in balance. As pitch drops, pianos sound duller as these partials fade in intensity.