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A brief description of how the piano worksThere are normally 88 keys on a modern piano, each of which plays a different note. There are 52 keys coloured white, the naturals and 36 coloured black, the accidentals. As you depress a key on the piano a felt covered hammer strikes tensioned strings via several mechanical linkages - this mechanical assembly is called the 'Action'. There are normally over 200 strings all adjusted (tuned) to give the correct pitch for the note played. There are 3 strings per note in the tenor and treble, 2 in the upper bass and 1 in the lower bass. The tension of each string varies from 225 pounds in the bottom bass to 180 pounds in the top treble. The overall tension exerted on the frame of the piano is around 18 tons. As the key moves down to the bottom of it’s' travel a felt covered damper is moved off the strings so they can vibrate. When the key is released the damper is allowed to move back on to the strings, thus muting the note. When the sustain pedal (right hand pedal) is depressed all the dampers are held off the strings, allowing the played notes to carry on sounding even after the key is released. The vibrations of the strings pass through the soundboard bridge onto the soundboard which amplifies the sound to make it loud enough to be heard. Each string is terminated by a small tuning pin firmly driven into a laminated plank of wood called the Wrest Plank. The piano tuner has a special tool that fits onto the tuning pins to allow the instrument to be tuned. Piano tuning is a very precise art that takes several years of training. When the tuner increases the tension of the string the pitch gets sharper and when the tension is reduced the pitch gets flatter. A piano should be tuned twice a year to keep it in good tune and at pitch. The pitch of the instrument is measured at note A (49), the A above middle C, which should have a frequency of 440 Hertz - this is often referred to as Concert Pitch or British Standard Pitch.
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