Following are excerpts from
THE PIANO: A Piano Technicians Guide for the Piano Owner
by Phil Gurlik, RPT
Fifth Edition Copyright © 2010 by Potter Press
A Division of the
Randy Potter School of Piano Technology, Inc.
61592 S.E. Orion Drive, Bend, Oregon 97702
Used by permission.
How the piano works
When you play a note on the piano, there can be over 130 parts in motion. The moving mechanism of the piano that the keys act upon is called the ACTION. The entire action can contain 11,500 or more moving parts. The proper relationships between these parts and their conditions are critical for the action to respond properly.
These thousands of small wood, felt, metal, leather, and sometimes plastic parts in the piano action have dozens of adjustments which need to be correct within thousandths of an inch. Some adjustments are so small that they need to be done by "feel." The proper adjustment of these moving parts, including the keys, is called REGULATING the action.
Most pianos have three pedals, some have only two. Most pianists use only the one on the right; the sustain pedal. The sustain pedal lifts all the of the dampers, allowing the strings of all the notes to vibrate. Any note played will be sustained while the sustain pedal is depressed. It is often inaccurately called the "loud" or "damper" pedal.
The left pedal is the soft pedal. In most vertical and some older grand pianos this pedal operates a lever which moves the hammers closer to the strings. While not that effective, it does allow the instrument to be played more lightly. On most grands, this is the una corda pedal. Depressing it shifts the action over so that the hammers strike only one or two strings, lowering the volume level.
The middle pedal operates the bass sustain on most vertical and some grand pianos; depressing it will sustain only the bass notes. With some verticals, it lowers a strip of muffler felt (a practice bar) between the hammers and the strings, muffling the tone. On other pianos, primarily grands and more expensive uprights, the middle pedal is the sostenuto. This pedal sustains only the notes that are held down while it is depressed.
Caring for the Piano
Bartolommeo Cristofori is credited with designing the first piano action in 1707. He built the first piano forte (meaning soft and loud) about 1720. Before then, almost all stringed keyboard instruments had strings that were plucked, rather than struck by hammers, which limited the dynamic possibilities. To achieve dynamic control, the piano forte action had to be much more intricate and therefore more carefully adjusted to function reliably.
Though pianos have changed extensively since these early instruments were developed, the basic principles have remained the same. It remains a challenge to keep these mechanical marvels working to their maximum potential.
Have the piano serviced regularly; you will save money in the long run.
Piano manufacturers recommend 3 to 4 tunings during the first year and a minimum of 2 tuning per year thereafter. Teachers, professional pianists, and club owners will often have their pianos serviced much more frequently - some have them checked every week or two. Pianos in concert halls are tuned before every performance; a piano will stay in perfect tune only a short time.
Although many piano owners do not have their instruments tuned the minimum twice per year that is recommended, at the very lest the piano should be stabilized at standard pitch and tuned yearly.
Because a piano's strings exert some 40,000 pounds of tension on the frame and harp, a piano will go out of tune even if it is not played. In addition, changes in humidity and temperature, string stretching, heavy playing, and frequent moving, such as in the school environment, all have an effect on the length of time a given piano will remain in adequate tune. The most critical time for a piano is when it is new. Many people are surprised to learn that a newer piano will go out of tune much sooner than one which has been used and serviced for a year or two. New piano strings stretch and drop in pitch quickly, much like new guitar or violin strings. Structural parts of a new piano settle, which prevents string positions from stabilizing.
What is A = 440?
A = 440 is the standard pitch level used on all instruments throughout the world. Because of this pitch standard, any instrument in the world can be in tune with any other. The particular note A = 440 on the keyboard is the 'A' above middle 'C'. The 440 means that the string is vibrating 440 times per second. The rest of the keyboard is tuned to this reference note.
A piano needs to be "up to pitch" at A = 440 for it to deliver its most pleasing tone. A piano low in pitch can be in tune with itself, but the tone quality will suffer. This is the case on some very old pianos where the danger of structural failure prevents them from being raised up to pitch. Most pianos in this condition make unsatisfactory musical instruments. If a piano is not up to A = 440, it will be difficult or impossible to play with other musical instruments. Students will develop a good sense of pitch if exposed to a properly tuned instrument.
A piano which is not close to the proper pitch level requires extra work to get it up to pitch. If the pitch is low, the tuner must go over the piano more than once, perhaps several times before fine tuning. He may even have to make another trip or two before the piano is stabilized. In any case, the piano should be tuned again before the pitch drops back down. A basic tuning fee generally includes tuning the piano once. If extra pitch raising works is necessary, there will usually be an additional charge. Often customers are surprised at the overall improvement in tone quality of their piano when it has been raised up for 1/4 to 1/2 step or more in pitch - aside from the improvement in the tuning itself.
Sometimes during pitch raising or even regular tuning, a weak string will break because of the additional strain of tuning. It is the responsibility of the customer to pay for its replacement. A new string will quickly stretch and drop in pitch. The piano technician can either mute off the new string with a piece of felt so that it will not sound objectionable, or he can return in a week or two and re-tune it.
What Time of Year Is Best To Tune a Piano?
Piano owners often ask which time of the year is best for having a piano tuned. This is an area of great confusion. As the seasons change, humidity and temperature levels fluctuate within the home. Climactic factors can have a dramatic effect on the tuning of a piano, depending upon the severity of the fluctuations. There are humidity control devices available at modest cost which limit the severity of climatic and seasonal changes on a piano; these are discussed in greater depth under "Humidity Control."
The wisest thing the owner can do is be consistent in tuning the piano. If the piano is tuned only once per year, it should be tuned approximately the same time each year, whether it be summer, fall, winter or spring. Likewise, if the piano is tuned two or more times per year, the spacing should be consistent. If a piano is badly out of tune, the best time to tune it is as soon as possible -- whatever time of year it is!
Piano owners sometimes wonder if tuning the piano on a rainy day is a good idea. Due to the relatively short time period involved, the humid air of a rainy day will not have a great effect on the tuning of a piano. The sensitive wooden parts of the piano, especially the soundboard, will generally take a week or two to have major reactions toward normal humidity and temperature changes. It is best if the piano is at normal temperature when the tuner arrives, and the temperature remains constant while he tunes.
Excessive humidity can cause rust to develop on the piano strings, tuning pins and other metal parts. It can also cause sticking keys and sluggish action parts, an even more immediate frustration for the piano's owner.
Excessive dryness can cause rattling keys, wobbly action parts, slipping tuning pins and cracks to appear in the sound board.
Winter dryness and summer humidity each cause tuning instability: Changes in humidity can also cause regulation problems.
The numerous wood parts (an average piano has from 9,000 to 14,000 parts), and especially the soundboard, absorb moisture and expand as the humidity rises. As the sound board accepts moisture it swells, pulling the strings tighter and raising the pitch. When the humidity decreases the wood shrinks, allowing the strings to slacken slightly, and the pitch to fall. There can be quite a dramatic rise or fall in the pitch level during a drastic humidity change, and the piano will change unevenly, throwing it out of tune. This is a common problem in churches and schools, where the air conditioning or heating units are turned on and off during the week.
Humidity control devices are available for pianos, and they are highly recommended. They are installed directly in the piano by your piano technician for a modest expense. The system is designed to maintain the piano's humidity level at approximately 42% Relative Humidity (R.H.), the recommended level by piano manufacturers. These devices are most effective on vertical pianos, as they are installed inside the case, out of sight, and can better control the pocket of air inside the instrument. For grand pianos the system is installed under the sound board, inside the rim of the piano. All of the major piano manufacturers recommend properly installed humidity control systems to control the humidity in the piano.