Piano Tuning Basics


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Problems with Temperature

It is very often the case that fluctuations in temperature go hand in hand with fluctuations in relative humidity, but it is not an absolutely necessary correlation. Nevertheless, the piano's reaction to very sudden or sizable temperature variations is similar to changes in humidity. Significant variance in the air temperature surrounding the piano will inevitably alter the pressure of the piano's strings against the bridge. The result is altered modulation. A significant increase in temperature will cause the piano to go sharp, while a decrease in temperature will cause the piano to go flat.

American homes with modern, forced air conditioning units often keep interior air temperatures at a fairly constant level, even between seasons. With such units, fluctuations in temperature are usually slight enough and within a small enough degree range that changes in the piano's down bearing are kept to a minimum. Although problems can arise when the units are suddenly turned off for periods of time, such as weekend trips or extended summer vacations. To avoid drastic changes in temperature, it is better to very gradually adjust the temperature in the room to one that is not greater than ten degrees of normal. Upon returning, avoid any rapid change by slowly adjust the temperature back to the desired level.

Problems with New Strings

Even though piano strings are usually made with amazingly strong, high quality steel, they inevitably stretch, especially when new. The stretching phase of new strings on an older piano, as well as factory installed strings on a new piano, takes some time. During the first two years after new strings have been installed, the piano will go flat after each tuning. If the piano is tuned every six months during the first year and a half, usually by the third tuning, the piano strings will have stabilized. By the fourth tuning, the strings will have stretched and the pitch becomes much more stable and, other structural and environmental circumstances notwithstanding, the piano begins to stay in tune for longer periods of time.

There is a string stretching tool that is sometimes used on new strings, but if used improperly, the tool can over stretch the strings. Because of this, professional technicians usually prefer to allow the strings to stretch on their own.

Problems with Tuning Pins

One of the main reasons why piano owners choose to have their pianos restored is because the pinblocks are in need of replacing. Good pinblocks are made of strong, dense hardwood. When newly installed, the pinblock holds the tuning pins tightly in place, which helps the piano stay in tune. Through years of climate change, the holes in the wooden pinblock fluctuate. With higher levels of humidity, the holes expand. As the humidity lowers, the holes contract. This reaction to climate is inevitable, and over time, the holes will no longer be able to hold the strings tight within the block. New, slightly larger pins can replace the old pins to once again achieve a tight fit. Certain types of 'super glues' can be applied as well. Eventually, though, the pinblock will ware itself out and in order for the piano to maintain a proper pitch level, the pinblock will need to be replaced.

Replacement of the pinblock is a main feature of professional piano restoration. The pinblock is very carefully removed from the piano and used as a template for building a new one. Once an exact replica has been cut from new, kiln dried hardwood stock, the pin holes are newly drilled using an industrial drill press. With the technician's expertise, the new pinblock is glued and doweled into place, the pins are inserted into their new holes, and the piano is restrung.

A Note About Work Performed

As a part of the Terms of Service at Sweeney Piano, it is good to know that all diagnostic judgments made by Michael Sweeney and other qualified employees of Sweeney Piano are based upon the fact that each piano is unique with its own particular, individual and exclusive needs. This is to say that because each piano calls for differentiating judgments based upon its literal and factual origin, its design and architecture, its quality of parts, its present physical condition, its environmental history, its maintenance history and other incidental factors, the judgment for and determination of the exact plan and sequence of technical procedures to be performed will differ from piano to piano. Because each piano is unique, Michael Sweeney guarantees a prescribed repair, restoration and/or maintenance plan that matches your piano's particular needs. Be assured that your piano will not receive unnecessary work, nor will you be billed for work that is unnecessary.

Why Pianos Need Tuning

It's a fact of the physical world: all pianos go out of tune. There are objective and environmental reasons which, if discovered, will help explain why some pianos go out of tune more quickly than others. Once discovered, certain conditions can be removed or controlled. Still, all pianos are susceptible. In typical American homes, but and even in halls designed and built specifically for housing pianos and other acoustic instruments, such factors are common and will surely affect even the highest quality pianos.

The professional technician looks for clues: How new or how old are the strings? Is there rust present? How much time has lapsed between tunings? Is the pinblock damaged? Are the tuning pins tight? Are there major temperature changes taking place in the room? Is the room drafty? Are there windows left open, then closed, then opened again? Does the piano sit next to a window? Does the piano receive direct sunlight? Does the piano sit next to an exterior wall? Does the piano sit over a furnace or air conditioning vent? Is there high humidity or extreme moisture fluctuations between the seasons? Is the piano played often? Is the piano played loudly?

Contributing factors and combinations of factors will vary from situation to situation, but every piano will inevitably be exposed to one or more of these typical circumstances. It is the professional technician who will diagnose the piano's situation, and work to correct or eliminate the possible causes.

Problems with Humidity

The problem of extreme changes in relative humidity is probably the most common reason for a piano to go out of tune, especially in regions where humidity fluctuations between the seasons are severe. In the East Coast, for example, especially in older homes using oil heated radiators for heat in the winter, it is often the case that the moisture content of the air inside the house is anything but constant. Summers are humid, moist and muggy while winter interiors become bone dry. These changes affect the piano's pitch because the soundboard absorbs the moisture in the wet season, then dehydrates again during the dry season. The changes, which are not visibly noticeable, cause the crown to expand and contract. The slight variations alter the string's pressure against the bridge (what's called the "down bearing"). Thus, as the humidity increases, the piano goes sharp and as the humidity decreases, the piano goes flat. In other parts of the country, it might be the case that the seasonal changes are reversed, such as in the desert regions of the Southwest, where the summers are hot and dry and the winters are cold and moist. Nevertheless, the results will be the same: a piano that needs tuning.

There are ways to help control changes in pitch caused by seasonal fluctuations in humidity. The most common, least expensive and efficient climate control solution is to have a professional piano technician equip your piano with a humidity control system especially built for this very purpose.