Piano maintenance

The piano requires various forms of maintenance to produce its best sound. Maintenance is also important for the appearance of the piano.

Care by Technician

Tuning

Main article: Piano tuning

Pianos that are prized by their owners are tuned regularly, usually once every six months for domestic pianos, and always just before a performance in concert halls. The longer a piano is left out of tune, the more time and effort technician will need to restore it to correct pitch. When a piano is only slightly out of tune, it loses the glowing tonal quality characteristic of a freshly tuned piano, probably because strings slightly out of tune with one another have weaker sympathetic vibrations. Pianos that are more than slightly out of tune tend to be unpleasant to play and listen to, to an extent that varies with the ear of the listener. Tuning hammers are the main tool that piano technicians use.

Pianos go out of tune primarily because of changes in humidity. Tuning can be made more stable by installing special equipment to regulate humidity, inside or underneath the piano. There is no evidence that being out-of-tune permanently harms the piano itself. However, a long-term low-humidity environment may eventually crack the soundboard and warp keys and other wooden parts. In particular, pianos located in arid climates and otherwise very dry rooms (for example, a cold climate with an extended heating season) require special attention to humidity control.

There are a growing number of musicians and composers who are tuning the piano to non-standard tunings, in order to achieve different kinds of harmony not possible with the standard 12-tone equal temperament tuning (normally found on the piano). Examples of such persons are La Monte Young, Terry Riley, and Michael Harrison - to name a few. Their tunings create never before heard of combinations of intervals (some large and some "micro") that lend themselves to many beautiful and interesting new harmonies, scales, and textural effects not possible in equal temperament. Of course, these brands of tuning are limited by the internal structure of the instrument itself. One must be very careful because the piano can only hold so much tension before it breaks.

Voicing

The felt hammers of the piano tend to harden over time. They also form grooves at the points of contact with the strings. Harder hammers produce a brighter tone quality, which may ultimately become harsh and undesirable. Piano technicians can soften hammers using special tools called voicing needles. They also sometimes use special hardening agents when the hammers are too soft (though this practice is controversial among some technicians). In either case, an important goal is uniform tone quality across the piano, since the hammers are not used with equal frequency and therefore tend to wear unevenly. How much and how forcefully the piano is played is a factor in how often a piano is voiced, as are the piano's setting and the preferences of its players.

Over time, the strings will wear grooves into the surface of the hammers. The grooves eventually become deep enough, and the head of the hammer flattened enough, that voicing cannot restore the piano's tone. At this point, a technician can file the hammers, restoring their original ovoid shape and pristine surface at the expense of making them somewhat smaller. This process may repeat several times, until there is not enough felt left on the hammers for another filing, and they must be replaced.

Regulation

Over time, the performance of a piano action tends to decline, due to the compression of felt, warping of wood, and other types of wear. A skilled technician can restore it to optimal precision, in a process called regulation, which involves adjustments ranging from turning a small screw to sanding down a wood surface. Many new pianos are not perfectly regulated when released from the factory, or quickly lose their regulation when moved to their new home, and benefit from regulation in the store or in the home.

The goal of regulation is to make the piano's touch and sound consistent across all notes, allow it to comfortably achieve the widest possible range of dynamics, and make the keys responsive to even the most rapid or most subtle motions of the player.

There are many dozens of types of regulation a piano may require. The most important include adjustment of:

Let-off, the point when the hammer disengages from the jack and flies freely. If the let-off is too large, it can be very difficult to achieve a pianissimo, to execute rapid trills, and to play powerful fortes; if too small, notes can acquire a "pinched" sound, or even block.

Drop, how far the hammers fall back after let-off. This affects the responsiveness of the action.

Repetition springs in a grand piano, which allow a hammer to repeatedly strike with minimal lifting of a key. If a spring is too springy, it can cause double-strikes; if not springy enough, it becomes difficult to repeat a note.

Key weights (and, in some actions, weight-regulating springs) control the inertia of the keys. A technician can add, remove, or change lead weights in the keys to change how light or heavy the keys feel to the player.

Restoration and Rebuilding

Pianos have a limited lifetime, usually measured in decades. However, different parts have different lifetimes: for example, on a heavily used but well-cared-for instrument, the hammers might last only ten years while the soundboard might last over a century. Regular replacement of worn parts can therefore extend a piano's lifetime by decades — even indefinitely, provided that the piano's structural support (i.e. the frame) remains sound.

In decrepit pianos, the frame and some parts of the action parts may remain in good condition, and piano rebuilders are able to restore or rebuild an instrument by replacing a large fraction of its parts. These include the strings, pinblock, bridges, soundboard and ribs, hammers, and many parts of the action. Colloquially, "restoration" implies more replacement work than mere "repair" or "maintenance," and "rebuilding" implies yet more intensive work than restoration. However, there is no precise definition of these terms.

Restoration is labor-intensive, and therefore expensive; it is therefore generally done only if the original piano was of high quality, or the instrument has historical or sentimental value.

Care by Owner

Moving a piano

Moving a piano is a complicated process. There is risk to the piano, risk of bodily injury to the movers and others and risk to other property. Although moving a piano may appear to be a simple process, hidden factors compound the task. Pianos are complicated to move and should only be moved by professionals who are careful, properly trained, and insured. They must also have the proper equipment.

Upright (vertical) pianos are the most common and the easiest to move. They are moved by tipping the piano and sliding a piano movers' dolly underneath or lifting the piano up onto the dolly. The dolly has a strong frame for moving and large rubber wheels for ease of moving and not scratching the floor. The piano is transported to its new location and removed from the dolly. The piano should be covered to avoid scratching or damaging it.

The wheels attached to vertical pianos themselves are rarely designed for moving, and are primarily used for cosmetic effects. With studio pianos that have larger, double wheels, they are designed for short moves. When moving studio pianos beyond the immediate room or for more than just a few feet, a dolly should still be used.

Grand pianos are moved by covering the piano, removing the left leg, and gently lowering the piano over onto its straight side. The piano is then lifted up onto a flat, padded board called a 'skid board'. The lid is allowed to overhang the side so as to not pressure it. The piano is blanketed, strapped down and the other legs and pedal lyre are removed. (*NOTE: The "pedal lyre" should be removed first before removing the left leg, since it does not support any weight) Additional care should be added to insure that the piano parts that can rub together and scratch must be secured. The skid board with piano is tipped and a piano movers dolly is slid underneath for transport to its new location, where the procedure is reversed.

Contrary to popular legend, proper piano moving does NOT affect the tuning. Tuning is affected by changes in climate such as temperature and humidity. If a piano is properly covered during the move, it will not feel the environmental changes such as going from indoors to outdoors and back indoors again. The piano WILL go out of tune if exposed to a climate change such as going from a dry home to a humid home.

Humidity

Much of a piano is made of wood, and pianos are therefore extremely sensitive to the fluctuations in humidity. The piano's wooden soundboard is designed to have an arch, or crown. The crown increases or decreases with changes of humidity, changing the tension on the strings and throwing the instrument out of tune. Larger fluctuations in humidity can affect regulation, and even cause parts to crack. If humidity changes are extreme, the soundboard can warp so much that it collapses and loses its crown, which may require rebuilding or replacement of the instrument.

Piano owners can prevent these problems by controlling humidity. Most technicians recommend an indoor relative humidity in the range of 30% to 50%, kept as constant as possible. Keeping the piano away from air vents, heaters, open windows, open doors, direct sunlight, and the kitchen can help prevent damage, since all these are potential sources of sudden changes in humidity. However, even with these precautions, changes in weather will affect indoor humidity. Ideally, a piano owner would use a hygrometer in conjunction with a humidifier and dehumidifier and/or air conditioner to keep the humidity of the room housing the piano constant year-round. In cases where controlling room humidity is impractical, an in-piano humidity control system (such as the Dampp-Chaser) may help, though there is some controversy among technicians about the efficacy of these systems.

Contaminants

Pianos are easily damaged by liquids. Liquid spills may only damage the exterior finish; however, a spill which reaches the inside of the piano can cause costly damage to the action or soundboard. Piano owners should protect their instruments by keeping liquids away from the instrument. Dust in between the keys can interfere with the action but can be minimized by keeping the lid closed when the instrument is not in use, however, the lid should be opened at times to ensure air circulates to prevent mold from growing. If a spill occurs, immediate action should be taken by removing the keys, cleaning them in a grease cutting solution and allowing them to dry. Careful disassembly, and reassembly should be taken if done by anyone other that a technician

Appearance

Pianos are fine furniture, and in this role they benefit from cleaning and polishing, done carefully to avoid introduction of any fluids into the piano's interior. For many piano finishes, dust removal is better done with a feather duster than a cloth, which minimizes the abrasive effect of the dust. A piano technician should be consulted for recommendations on cleaning and polishing products suitable for a piano.

References

Arthur A. Reblitz: Piano Servicing, Tuning and Rebuilding/ for the Professional, the Student and the Hobbyist. ISBN 0911572120) (HC), ISBN 1879511037 (Pbk.). Lanham, Maryland: The Vestal Press, 1993.
Larry Fine, The Piano Book. ISBN 1-929145-01-2
PIANO SOLUTIONS XXI, Piano Restoration Shop.

External links

Piano Technicians Guild - Information on piano maintenance and becoming a Registered Piano Technician.