Keyboard and pedals
Almost every modern piano has 88 keys (seven octaves and a bit, A to C). Many older pianos only have 85 (from A to A), while some manufacturers extend the range further in one or both directions. The most notable example of an extended range can be found on Bösendorfer pianos, some of which extend the normal range downwards to F, with others going as far as a bottom C, making a full eight octave range. On some models these extra keys are hidden under a small hinged lid, which can be flipped down to cover the keys and avoid visual disorientation in a pianist unfamiliar with the extended keyboard. The extra keys are added primarily for increased resonance; that is, they vibrate sympathetically with other strings whenever the damper pedal is depressed. Only a very small number of works composed for piano actually use these notes. More recently, the Stuart and Sons company has also manufactured extended-range pianos.
For the arrangement of the keys on a piano keyboard, see Musical keyboard. This arrangement was inherited from the harpsichord without change, with the trivial exception of the color scheme (white for naturals and black for sharps) which became standard for pianos in the late 18th century.
Pianos have had pedals, or some close equivalent, since the earliest days. (In the 18th century, some pianos used levers pressed upward by the player's knee instead of pedals.) The three pedals that have become more or less standard on the modern piano are the following.
The damper pedal is often simply called "the pedal," since it is the most important. It is placed as the rightmost pedal in the group. Every note on the piano except for (approximately ) the top two octaves is equipped with a damper, which is a padded device that prevents the strings from vibrating. The damper is raised off the strings of its note whenever the key for that note is pressed. When the damper pedal is pressed, all the dampers on the piano are lifted at once, so that every string can vibrate. This serves two purposes. First, it permits notes to be connected (i.e., played legato) when there is no fingering that would make this possible. More important, raising the damper pedal causes all the strings to vibrate sympathetically with whatever notes are being played, which greatly enriches the tone.
Piano music starting with Chopin tends to be heavily pedaled, as a means of achieving a singing tone. In contrast, the damper pedal was used only sparingly by the composers of the 18th century, including Haydn, Mozart and Beethoven; in that era, pedaling was considered primarily as a special coloristic effect.
The soft pedal or "una corda" pedal is placed leftmost in the row of pedals. On a grand piano, this pedal shifts the action to one side slightly, so that hammers that normally strike all three of the strings for a note strike only two of them. This softens the note and also modifies its tone quality. For notation of the soft pedal in printed music, see Italian musical terms.
The soft pedal was invented by Cristofori and thus appeared on the very earliest pianos. In the 18th and early 19th centuries, the soft pedal was more effective than today, since it was possible at that time to use it to strike three, two or even just one string per note—this is the origin of the name "una corda", Italian for "one string". In modern pianos, the strings are spaced too closely to permit a true "una corda" effect—if shifted far enough to strike just one string on one note, the hammers would also strike the string of the next note over.
On upright pianos, the soft pedal is replaced by a mechanism for moving the hammers' resting position closer to the strings. This reduces volume, but does not change tone quality as a true "una corda" pedal does.
The sostenuto pedal or "middle pedal" maintains in the raised position any damper that was raised at the moment the pedal was depressed. It makes it possible to sustain a note while the player's hands have moved on to play other notes, which can be useful for musical passages with pedal points and other tricky situations. The sostenuto pedal was the last of the three pedals to be added to the standard piano, and to this day many cheap pianos—and even a few good ones—do not have a sostenuto pedal. A number of twentieth-century works call for the use of this pedal.
The materials of the piano
Many parts of a piano are made of materials selected for extreme sturdiness. The outer rim of the piano, is made (in quality pianos) of a hardwood, normally maple or beech. According to Harold A. Conklin, the purpose of a sturdy rim is so that "the vibrational energy will stay as much as possible in the soundboard instead of dissipating uselessly in the case parts, which are inefficient radiators of sound." The rim is normally made by laminating flexible strips of hardwood to the desired shape, a system that was developed by Theodore Steinway in 1880.
The thick wooden braces at the bottom (grands) or back (uprights) of the piano are not as acoustically important as the rim, and are often made of a softwood, even in top-quality pianos, in order to save weight.
The pinblock, which holds the tuning pins in place, is another area of the piano where toughness is important. It is made of hardwood, and generally is laminated (built of multiple layers) for additional strength and gripping power.
Piano strings, which must endure years of extreme tension and hard blows, are made of high quality steel. They are manufactured to vary as little as possible in diameter, since all deviations from uniformity introduce tonal distortion. The bass strings of a piano are made of a steel core wrapped with copper wire, to increase their flexibility. For the acoustic reasons behind this, see Piano acoustics.
The plate, or metal frame, of a piano is usually made of cast iron. It is advantageous for the plate to be quite massive. Since the strings are attached to the plate at one end, any vibrations transmitted to the plate will result in loss of energy to the desired (efficient) channel of sound transmission, namely the bridge and the soundboard. Some manufacturers now use cast steel in their plates, for greater strength. The casting of the plate is a delicate art, since the dimensions are crucial and the iron shrinks by about one percent during cooling. The inclusion in a piano of an extremely large piece of metal is potentially an esthetic handicap. Piano makers overcome this handicap by polishing, painting, and decorating the plate; often plates include the manufacturer's ornamental medallion and can be strikingly attractive.
The numerous parts of a piano action are generally hardwood or plastic. The choice between these two materials is controversial. Some varieties of plastic, incorporated into pianos in the 1950's and 1960's, were clearly disastrous, crystallizing and losing their strength after one or two decades of use. The Steinway firm once used Teflon, a plastic, for some action parts, but ultimately abandoned the experiment. More recently, the Kawai firm has built pianos with action parts made of more modern and effective plastics; these parts have held up better and have generally received the respect of piano technicians.
The part of the piano where materials probably matter more than anywhere else is the soundboard. In quality pianos this is made of solid spruce (that is, spruce boards glued together at their edges). Spruce is chosen for its high ratio of strength to weight. The best piano makers use close-grained, quarter-sawn, defect-free spruce, and make sure that it has been carefully dried over a long period of time before making it into soundboards. In cheap pianos, the soundboard is often laminated; i.e. made of plywood.
Piano keys are generally made of spruce or basswood, for lightness. Spruce is normally used in high-quality pianos. Traditionally, the white keys were covered with strips of ivory, but since ivory-yielding species are now endangered and protected by treaty, plastic is now universally used. The Yamaha firm innovated a plastic, since imitated by other makers, that mimics the feel of ivory on the player's fingers.
The requirement of structural strength, fulfilled with stout hardwood and thick metal, makes pianos heavy. Even a small upright can weigh 300 pounds (136 kg.), and the Steinway concert grand (Model D) weighs 990 pounds (480 kg). The largest piano built, the Fazioli F308, weighs 1520 pounds (691 kg).
Care and maintenance of pianos
Pianos that are prized and appreciated by their owners are tuned regularly, roughly once every four to six months for domestic pianos, and always just before a performance in concert halls. The effect of being out of tune depends on degree. 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.
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 actually harms the piano itself.
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 undesirable. Piano technicians can soften hammers using special tools. They also sometimes use special solvents that can harden a hammer. 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. The process of altering the hardness of piano hammers is called voicing. Voicing image, from the Sc
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