Guide to the piano: Day Five
The strings on a piano are divided into three groups. From the top left the bass strings run diagonally downwards. The next group of strings is the low treble or tenor, and the highest octaves are called the high treble.
A piano needs to have long, thick strings to produce the low notes, and short, thin strings to produce the high notes. In a modern piano, these strings are stretched across the cabinet diagonally to save space. For the low strings, copper wire is wound around them to make them extra thick.
Long, thick strings naturally sound fuller and louder and carry on sounding for longer than short, thin strings. To prevent them overbalancing the high ones, the strings are arranged so that you actually strike three strings all tuned to the same note, simultaneously when you play any key in the highest five octaves. In the lowest bass section, each hammer only strikes one string at a time, and in between there are a small number of notes – each with two identially-tuned strings. These sets of two or three strings are called unisons.
Most pianos have around two hundred and twenty strings in total. Together, they exert a force of up to twenty tons. To resist this huge tension, pianos have a heavy cast-iron frame, otherwise known as a plate. Together with the backposts, this frame is the backbone of a piano.
The strings are tuned by turning the tuning pins, which are set into the pinblock, a sturdy block made up of layers of wood: this is usually hidden behind the frame. All strings run over a bridge: a long narow piece of wood which transmits the vibrations of the strings to the soundboard. The bass strings have a separate, smalller bridge.
Tomorrow… Grand pianos
