Harpsichords vary in size and shape, but they all have the same basic functional arrangement. The player presses a key, which causes the far end of the key to rise. This lifts a jack, a long strip of wood, to which is attached a small plectrum (a bit of quill or plastic), which plucks the string. When the key is released by the player, the far end returns to its rest position and the jack falls back. The plectrum, mounted on a tongue that can swivel backwards away from the string, passes the string without plucking it again. As the key reaches its rest position, the string's vibrations are halted by the damper, a bit of felt attached to the top of the jack.
These basic principles are explained in more detail below.
Simply plucking strings produces a feeble sound: the sonority of the harpsichord arises from its design to amplify it. The strings pass over a bridge-like nut, a sharp edge supporting one end of their vibrating length, which is firmly attached to a soundboard, a thin panel of wood usually made of spruce or (in Italian harpsichords) cedar. The soundboard and case-construction efficiently transduces the vibrations of the strings into vibrations in the air. Also, in harpsichords with more than one choir of strings the vibrations of one string will invite its adjacent twin string to resonate in sympathy as long as the key is pressed. Some harpsichords have a 'damper off' position so that one choir of strings is undamped and may resonate freely in response to the tones played on the other choir(s).
Each string is held at the proper tension to sound the correct note. At one end, generally closest to the keyboard, each string is wound around a tuning pin, so that its tension may be adjusted by rotating the pin with a wrench (or tuning hammer). The tuning pins are held tightly in holes drilled in the pinblock or wrestplank, an oblong hard-wood plank. The other ends of the strings are fitted with twisted loopholes that pass over the hitchpins which are driven into the liner.
Many harpsichords have exactly one string per note. There are several reasons why it is sometimes an advantage to have more. When there are two choirs of strings at the same length, it is possible to arrange for them to give different tonal qualities, and thus to increase the variety of sound produced by the instrument. This is done by having one set of strings plucked closer to the nut (the bridge-like device that terminates the sounding length of the strings) than the other. Plucking close to the nut emphasizes the higher harmonics, and produces a "nasal" sound quality. When two strings tuned to be the same pitch, or to an octave apart, are plucked simultaneously by a single keystroke, the note is louder and richer than one produced by a single string. The qualitative distinction is particularly noticeable when the strings are tuned an octave apart.
When describing a harpsichord it is customary to specify its choirs of strings, often called its disposition. Strings at eight foot pitch sound at the normal expected pitch, strings at four foot pitch sound an octave higher, and sometimes harpsichords have the rare 16-foot pitch (one octave lower than eight-foot) or two-foot pitch (two octaves higher).
When there are multiple choirs of strings, the player is often able to control which choirs sound. This is usually done by having a set of jacks for each choir, and a mechanism for "turning off" each set, often by moving the upper register (through which the jacks slide) sideways a short distance, so that their plectra miss the strings. In simpler instruments this is done by manually moving the registers, but as the harpsichord evolved levers, knee levers and pedal mechanisms were invented that made it easier to change registration.
More flexibility in selecting which strings play is available in harpsichords having more than one keyboard or manual, since each manual can control the plucking of a different set of strings. In addition, such harpsichords often have a mechanism to couple manuals together, so that two can be used while actually playing on only one. The most flexible system is the French shove coupler, in which the lower manual can slide forward and backward, so that in the backward position "dogs" attached to the upper surface of the lower manual engage the lower surface of the upper manual's keys. Depending on choice of keyboard and coupler position, the player can select any of the sets of jacks labeled in figure 4 as A, or B and C, or all three.
The English dogleg jack system is less flexible, in that the manuals are immobile. The dogleg shape of the set of jacks labeled A in figure 5 permits A to be played by either keyboard, but the lower manual necessarily plays all three sets, and the player cannot select just B and C as in the French shove coupler.
The use of multiple manuals in a harpsichord was not originally provided for the flexibility in choosing which strings would sound, but rather for transposition; for discussion see History below.
Harpsichords with pedal keyboards, to be played with the feet, were also manufactured, mostly as practice instruments for organists.
The case holds in position all of the important structural members: pinblock, soundboard, hitchpins, keyboard, and the jack action. It usually includes a solid bottom, and also internal bracing to maintain its form without warping under the tension of the strings. Cases vary greatly in weight and sturdiness: Italian harpsichords are often of light construction; heavier construction is found in the later Flemish instruments and those derived from them (see History, below).
The case also gives the harpsichord its external appearance and protects the instrument. A large harpsichord is, in a sense, a piece of furniture, as it stands alone on legs and may be styled in the manner of other furniture of its place and period. Early Italian instruments, on the other hand, were so light in construction that they were treated rather like a violin: kept for storage in a protective outer case, and played after taking it out of its case and placing it on a table. Such tables were often quite high - until the late 18th century people usually played standing up. Eventually, harpsichords came to be built with just a single case, though an intermediate stage also existed: the "false inner-outer", which for purely aesthetic reasons was built to look as if the outer case contained an inner one, in the old style.. Even after harpsichords became self-encased objects, they often were supported by separate stands, and some modern harpsichords have separate legs for improved portability.
Many harpsichords have a lid that can be raised, a cover for the keyboard, and a stand for music.
Harpsichords have been decorated in a great many different ways: with plain buff paint (e.g. some Flemish instruments), with paper printed with patterns, with leather or velvet coverings, with chinoiserie, or occasionally with highly elaborate painted artwork.
The terms used to denote the various members of the harpsichord family are now standardized. This was not so in the harpsichord's heyday.
In modern usage, "harpsichord" can mean any member of the family of instruments. More often, though, it specifically denotes a grand-piano-shaped instrument with a roughly triangular case accommodating long bass strings at the left and short treble strings at the right. The characteristic profile of such a harpsichord is more elongated than a modern piano, with a sharper curve to the bentside.
The virginals is a smaller and simpler rectangular form of the harpsichord having only one string per note; the strings run parallel to the keyboard which is on the long side of the case.
A spinet is a harpsichord with the strings set at an angle (usually about 30 degrees) to the keyboard. The strings are too close together for the jacks to fit between them. Instead, the strings are arranged in pairs, and the jacks are in the larger gaps between the pairs. The two jacks in each gap face in opposite directions, and each plucks a string adjacent to a gap.
Since the strings run vertically, the jacks move horizontally, making the action of clavecytheria more involved than in a harpsichord.
Some of the earliest harpsichords for which we have evidence are clavicytheria. One surviving example from the late 15th century is kept at the Royal College of Music in London. The clavicytherium may have been one branch of the early development of the harpsichord action (see below, History), that was almost entirely surpassed by the horizontal harpsichord which has the advantage of being able to rely on gravity to return the jacks to their rest position.
Clavicytheria were occasionally made throughout the historical period. In the 18th century particularly fine clavicytheria were made by Albertus Delin, a Flemish builder..
Several harpsichords with unusual keyboard layouts, such as the archicembalo, were built in the 16th century to accommodate variant tuning systems demanded by compositional practice and theoretical experimentation.
On the whole, earlier harpsichords have smaller ranges and later ones larger, though there are many exceptions. The largest harpsichords have a range of just over five octaves and the smallest have under four. Usually, the shortest keyboards were given extended range in the bass with a "short octave".
Tuning pitch is often taken to be a=415 Hz, roughly a semitone lower than the modern standard concert pitch of a=440 Hz. An accepted exception is for French baroque repertoire which is often performed with a=392 Hz, approximately a semitone lower again. Tuning an instrument nowadays usually starts with setting an A; historically it would commence from a C or an F.
The harpsichord was most probably invented in the late Middle Ages. By the 1500's, harpsichord makers in Italy were making lightweight instruments with low string tension. A different approach was taken in Flanders starting in the late 1500s, notably by the Ruckers family. Their harpsichords used a heavier construction and produced a more powerful and distinctive tone. They included the first harpsichords with two keyboards, used for transposition.
The Flemish instruments served as the model for 18th century harpsichord construction in other nations. In France, the double keyboards were adapted to control different choirs of strings, making a musically more flexible instrument. Instruments from the peak of the French tradition, by makers such as the Blanchet family and Pascal Taskin, are among the most widely admired of all harpsichords, and are frequently used as models for the construction of modern instruments. In England, the Kirkman and Shudi firms produced sophisticated harpsichords of great power and sonority. German builders extended the sound repertoire of the instrument by adding sixteen foot and two foot choirs; these instruments have recently served as models for modern builders.
In the late 18th century the harpsichord was supplanted by the piano and almost disappeared from view for most of the 19th century: an exception was its continued use in opera for accompanying recitative, but the piano sometimes displaced it even there. 20th century efforts to revive the harpsichord began with instruments that used piano technology, with heavy strings and metal frames. Starting in the middle of the 20th century, ideas about harpsichord making underwent a major change, when builders such as Frank Hubbard, William Dowd, and Martin Skowroneck sought to re-establish the building traditions of the Baroque period. Harpsichords of this type of historically informed building practice dominate the current scene.
The first music written specifically for solo harpsichord was published around the early 16th century. Composers who wrote solo harpsichord music were numerous during the whole Baroque era in European countries including Italy, Germany, England and France. Solo harpsichord compositions included dance suites, fantasias, and fugues. Besides solo works, the harpsichord was widely used for accompaniment in the basso continuo style (a function it maintained in operatic recitative even into the 19th century). Well into the 18th century, the harpsichord was considered to have some advantages over the piano.
Concertos for the instrument were written by Francis Poulenc (the Concert champêtre, 1927-28), Manuel de Falla, Bertold Hummel, Henryk Mikołaj Górecki, Philip Glass and Roberto Carnevale. Bohuslav Martinů wrote both a concerto and a sonata for the instrument, and Elliott Carter's Double Concerto is scored for harpsichord, piano and two chamber orchestras.
In chamber music, György Ligeti wrote a small number of solo works for the instrument (including "Continuum"), and Henri Dutilleux's "Les Citations" (1991) is scored for harpsichord, oboe, double bass and percussions. Both Dmitri Shostakovich (Hamlet, 1964) and Alfred Schnittke (Symphony No.8, 1998) wrote works that use the harpsichord as part of the orchestral texture.
Harpsichordist Hendrik Bouman has composed pieces in the 17th and 18th century style, including works for solo harpsichord, harpsichord concerti, and other works that call for harpsichord continuo. Other contemporary composers writing new harpsichord music in period styles include Grant Colburn, Miguel Robaina, Fernando de Luca and Gianluca Bersanetti.
The type of instrument now usually called harpsichord in English is generally called a clavicembalo (sometimes in the corrupt form gravicembalo, both masculine) or simply cembalo in Italian, and this last word is generally used in German as well (Cembalo, neuter). The Dutch word is klavecimbel (neuter). The typical French word is clavecin (masculine), though in French historical sources the word épinette (feminine, cognate with English spinet) is sometimes used, in a global sense, meaning any instrument with a harpsichord-like action. The standard Spanish word is clavecín (masculine), with clavicémbalo as an alternative (along with the rarer forms clavicímbalo and clavicímbano; all masculine). The Portuguese words are espineta (feminine) and cravo (masculine, cognate with the element clav- in the Italian words for the instrument).