Why does a piano go out of tune?
Humidity
Temperature Changes
Stretching of the strings
Slipping tuning pins
Playing
Summary
Piano strings are under a great deal of tension which is supported by the frame, plate, pin block, tuning pins, bridges and sound board. Anything which affects the positions of these parts will cause a change in tension and make the piano go out of tune.
Even though a soundboard is varnished, moisture from the air can seep into and out of the wood, causing the crown to increase and diminish. This is the most important factor causing a good piano to go out of tune. Atypical piano goes sharp in the spring when rain increases the humidity and thus the crown, and flat again in the early winter when the dry heat of the furnace removes moisture from the soundboard, diminishing the crown. This seasonable pitch change is noticeably absent from pianos which are kept in climate controlled (temperature and humidity controlled) environments.
When the temperature rises, the soundboard expands and increases its push on the strings. Since the room temperature surrounding a typical piano usually stays within 20° or so, this factor does not affect the tuning as much as humidity does. Temperature changes also have a slight effect on the strings, frame and plate, but this factor is even less important.
New music wire is very elastic; it begins to stretch as soon as it is pulled up to pitch. New strings stretch the most during their first few years in a piano. Because of its stretching, many new pianos sink a quarter step flat within a few months after each tuning, for two or three years; then the stretching decreases, and the pitch becomes stable for longer periods of time. Some piano makers and rebuilders stretch their new strings with a small roller immediately after a piano is pulled up to pitch. This procedure can be effective, but if overdone it may cause objectionable false beats in the treble.
This factor does not enter into the tuning of a good quality new piano. The pins in a new piano should be so tight that the string tension does not cause them to turn. In an older piano, however, which has been exposed to regular seasonal humidity changes for many years, the pin block loses its tight grip on the pins, from continual expansion and contraction. When the pins get loose enough, the strings rotate them slowly in the pin block and the pitch gradually goes down. Piano's which are transferred from a wet to a dry climate tend to get loose tuning pins.
The louder and more often a piano is played, the faster it goes out of tune. A piano with tight tuning pins is not "knocked" out of tune as fast, of course, as one with loose pins. But playing is a factor even in fine quality pianos.
Any piano has one or more factors at work to make it go out of tune. In addition, a poor tuner can leave a piano in tune but in a state that it will not stay that way very long. Some of these factors may be controlled by skill of the tuner; other may be corrected only by restringing or by controlling the climate. Humidity and temperature changes and hard use normally affect even a fine piano: that is why pianos must he tuned regularly. How often should a piano be tuned? This depends upon the condition of the piano and the musical demands of the owner. A piano which is mainly used as a piece of furniture probably would not "need" tuning more than once a year. A piano which is in regular use and is in good condition may get by with being tuned twice a year, each time a seasonal humidity change. A piano given a daily workout by a professional musician or serious student might need monthly or even more frequent tuning.
You can contact us to have your piano tuned.

Webmaster | Back to Top of Lukas van der Walt Piano Tuners Cape Town Western Cape South Africa - Piano Tuning | Site Map
Lukas van der Walt Piano Tuners is registered with the
South African Association of Professional Piano Tuners