Why Does A Piano Go Out Of Tune?
There are several factors that may cause a piano to go out of tune, but the main culprit is usually climate. The piano's soundboard is made of wood, which will expand in humid weather and contract in dry weather, altering the pitch of the piano. Changes in humidity are more significant than changes in temperature, but the more stable all climate conditions are kept, the more stable the piano will be.
Other common causes of tuning instability are moving a piano, which introduces a new climate, and new piano strings which will need time and sometimes multiple tunings before they are fully stretched. Loose tuning pins are common in older pianos, and are often to blame when one or two notes sound much worse than the others.
It is therefore important to keep your piano away from heating vents, exterior doors, and open windows. Tuning your piano twice a year will help each tuning perform better by keeping the piano stable.
