‘If you move a piano it goes out of tune?’ Everyone knows that!
Well, this may have been true once but has now turned into a bit of a myth. It is my opinion that old wooden framed pianos give rise to the traditional belief that if a piano is moved, even slightly, it will go out of tune. The wooden construction could distort easily affecting the tuning. Pianos with an iron frame will not go much out of tune if they are moved, if at all.
So why do pianos go out of tune?
A change of environment, whether from being moved or any other reason, can affect the tuning, usually over a period of days or weeks. This is because of the way the soundboard expands and contracts due to changes of temperature and humidity, causing the tension on the strings to alter. Playing the piano will affect the tuning too, because of the hammers striking the strings and causing them to vibrate.
So why do pianos go out of tune?
A change of environment, whether from being moved or any other reason, can affect the tuning, usually over a period of days or weeks. This is because of the way the soundboard expands and contracts due to changes of temperature and humidity, causing the tension on the strings to alter. Playing the piano will affect the tuning too, because of the hammers striking the strings and causing them to vibrate
Seasonal changes
The soundboard is the light coloured board seen through the strings.
Our changing seasons will often affect the tuning of the piano, usually because of the way changes of temperature and humidity affect the soundboard. The soundboard is a large, flat board, usually made from spruce and is responsible for resonance and volume. The strings are connected to the soundboard via what is called a ‘bridge’. When a note is played, vibrations from the string are transmitted to the soundboard which in turn vibrates the air.
Because of central heating, homes are often drier in the winter so the soundboard may shrink a little, causing the strings to lose some tension. The result is that the pitch of the piano goes slightly flat during the colder months. The process is then reversed during the summer when the soundboard expands, increasing the tension on the strings, causing the pitch to go higher.
This seasonal rise and fall in pitch is not uniform throughout the whole piano though. Usually a section in the centre, roughly from the octave below to the octave above middle C moves up or down the most. While the bass and top treble are affected to a lesser degree, if at all. Sometimes, if the higher notes seem suddenly to have gone flat it could be seasonal changes have caused the middle section to go sharp instead.
If a piano is not tuned at all for many years the tendency is for the pitch to gradually drop. This does not happen uniformly though. The bass section tends to hold up better and the treble goes increasingly flat making the instrument sound terrible. Provided the piano is in good enough condition, it can usually be tuned back up to the correct pitch without any permanent damage having occurred.
Problems such as loose tuning pins can cause notes to go out, or even render the piano un-tuneable. I’ll explain more about this and other piano related problems in another section.