The tuning of a piano is a very complex task that must be carried out by highly qualified personnel, since it requires a sharp ear and great sensitivity. If this task is undertaken without the essential knowledge, could cause irreparable damage to the instrument. For example, in a tuning session not is raised and lowered the instrument more than 30 cents (a cents is the hundredth part of a semi tone), since the sum of the tensions of the strings is 20 tons, approximately, and with a bad manoeuvre runs the risk of fracturing the headstock. The tempered tuning or equal temperament which is used most frequently today, however various types of tunings were used in the past. In the past, for example, was used more than 90 fair tunings, such as mesotonica, kirnberger III, werckmeister III and valotti to name a few, which are used in harpsichords for execution of former music.
These tunings despite having a splendid color and sonority had the disadvantage of not close intervals full circle, having to leave one of them (the fifth of the Wolf), imperfect therefore was impossible to walk through all the shades without changing the tuning. This made fall into disuse this beautiful sonority. Following this came the tuning range of well tempered in this are spread equitably the frequencies of their 12 semi tones. The mathematical representation shows the semi tone as the twelfth root of two. in this way we have to: the 440 hz x 12v2 = 466, 16 Hz (the #) where.
12v2 = 1,0594631 therefore note if it would be: 466,16 x 12v2 = 493, 88hz perform this scramble for hundredths of tone with absolute accuracy is an impossible task for human hearing. Apart from this subdivision there is an additional problem, as climbing octaves these should gradually increase its tone, while the bass octaves must decrease to be perceived in tune. Refers to these deviations inarmonicas curves. Each piano either by the size of their ropes or by hardness of them requires a specific inharmonic curve. Advance in acoustic piano investigations has led to an almost perfect level tuning technique, where the use of computational tools as a support to the ear of an expert is currently inescapable.