Musical keyboard
From Wikipedia, the free encyclopedia
A musical keyboard is the set of adjacent depressible levers or keys on a musical instrument, particularly the piano. Keyboards typically contain keys for playing the twelve notes of the Western musical scale, with a combination of larger, longer keys and smaller, shorter keys that repeats at the interval of an octave. Depressing a key on the keyboard causes the instrument to produce sounds, either by mechanically striking a string or tine (piano, electric piano, clavichord); plucking a string (harpsichord); causing air to flow through a pipe (organ); or strike a bell (carillon). On electric and electronic keyboards, depressing a key connects a circuit (Hammond organ, digital piano, synthesizer). Since the most commonly encountered keyboard instrument is the piano, the keyboard layout is often referred to as the "piano keyboard."
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[edit] Size and historical variation
The chromatic compass of keyboard instruments has tended to increase. Harpsichords often extended over five octaves (61+ keys) in the 18th century, while most pianos manufactured since about 1870 have 88 keys. Some modern pianos have even more notes (a Bösendorfer 225 has 92 and a Bösendorfer 290 "Imperial" has 97 keys). While modern synthesizer keyboards commonly have either 61, 76 or 88 keys, small MIDI controllers are available with 25 notes. Organs normally have 61 keys per manual, though some spinet models have 44 or 49. An organ pedalboard is a keyboard with long pedals which are played by the organist's feet. Pedalboards vary in size from 12 to 32 notes.
In a typical keyboard layout, black note keys have uniform width, and white note keys have uniform width and uniform spacing at the front of the keyboard. In the larger gaps between the black keys, the width of the natural notes C, D and E differ slightly from the width of keys F, G, A and B. This allows close to uniform spacing of 12 keys per octave while maintaining uniformity of seven "natural" keys per octave.
Over the last three hundred years, the octave span distance found on historical keyboard instruments (organs, virginals, clavichords, harpsichords, and pianos) has ranged from as little as 125mm to as much as 170mm. Modern piano keyboards ordinarily have an octave span of 164-165mm, but several reduced-size standards have been proposed and marketed. A 15/16 size (152 mm octave span) and the 7/8 DS Standard (140 mm octave span) keyboard developed by Christopher Donison in the 1970s and developed and marketed by Steinbuhler & Company. U.S. pianist Hannah Reiman has promoted piano keyboards with narrower octave spans and has a U.S. patent (#6,020,549) on the apparatus and methods for modifying existing pianos to provide interchangeable keyboards of different sizes.
There have been variations in the design of the keyboard to address technical and musical issues. During the sixteenth century, when instruments were often tuned in meantone temperament, some harpsichords were constructed with the G♯ and E♭ keys split into two. One portion of the G♯ key operated a string tuned to G♯ and the other operated a string tuned to A♭, similarly one portion of the E♭ key operated a string tuned to E♭, the other portion operating a string tuned to D♯. This type of keyboard layout, known as the enharmonic keyboard, extended the flexibility of the harpsichord, enabling composers to write keyboard music calling for harmonies containing the so-called wolf fifth (G-sharp♭ to E-flat♯), but without producing aural discomfort in the listeners. Other examples of variations in keyboard design include the Janko keyboard and the chromatic keyboard systems on the accordion and bandoneón.
On electric and electronic keyboards, there is an electric switch under each key. Depressing a key connects a circuit, which causes the tone generation mechanism to be triggered. Most electronic keyboards use a matrix circuit in which the rows and columns are made up of wiring. Without a matrix circuit, a 61-key keyboard would have to have 61 wires into the integrated circuit of the keyboard. With the matrix circuit, the entire keyboard can send signals to the integrated circuit with two matrices of eight wires that are conceptually arranged into columns and rows. The keyboard controller scans all of the columns, to determine if a key has been pressed. If a key in the column has been pressed, then the controller scan the rows, to determine which row has been activated. In a manner analogous to the children's board game "Battleship!", the keyboard controller determines which key has been pressed, and then closes the switch for that key's note. This entire process takes place so quickly that the performer is not aware of the delay. [1]
[edit] Playing techniques
Despite their apparent similarity, keyboard instruments of different types require different techniques. For instance, a piano will produce a louder note the harder the key is pressed. On the other hand, the volume and timbre of the sound on the pipe organ are dictated by the flow of air from the bellows and the stops selected by the player; in the harpsichord the strings are plucked and the volume of the note is not perceptibly varied by using a different touch on the keyboard. Players of these instruments must use other techniques to color the sound. The arranger keyboard uses preset drum rhythms that respond to chords played in the left hand by the instrumentalist, with other buttons and switches used to change rhythms and even the voice of the instrument.
Playing a keyboard instrument can prove to be a challenging task; even though the layout is quite simple and all notes are easily accessible, some music puts high demand on the performer's skills to play accurately and in tempo, and beginners will often struggle to produce a passable rendition of a simple piece due to technique deficiency, which takes training to improve. The sequence of movements executed by the playing hand can be almost arbitrarily complicated, with some possible problems being wide-spanned chords, which can be problematic for people with small hands, chords that require unusual hand positions which can initially be uncomfortable or even painful, and also fast scales, trills and arpeggios.
Playing instruments with dynamic keyboards (i.e. ones that respond to varying force with which the key is struck) may require independence of the fingers so that some fingers are able to strike harder while others play more softly. Players need to learn to coordinate two hands and use them independently. Most music is written for two hands; typically the right hand plays the melody in the treble range, while the left plays an accompaniment of bass notes and chords in the bass range. There exist pieces of non-trivial music written for the left hand alone, e.g. several of the Godowsky's 53 Studies on Chopin's Etudes and Ravel's Piano Concerto for the Left Hand. In music that uses counterpoint technique, both hands play different melodies at the same time.
[edit] Other uses
Other instruments share the keyboard layout, although they are not keyboard instruments. For example, the xylophone, marimba, vibraphone, and glockenspiel all have a separate-sounding tone bar of metal or wood for each note. These bars are laid out in the same configuration as a common keyboard.
[edit] Keyboards with alternate keys
There are some rare variations of keyboards with more or less than 12 keys per octave, mostly used in microtonal music.
Some free-reed instrument keyboards such as accordions and Indian harmoniums include microtones. Electronic music pioneer Pauline Oliveros plays one of these. Egyptian belly-dance musicians like Hassam Ramzy use custom-tuned accordions in order to play traditional scales. The small Garmon accordion played in the Music of Azerbaijan sometimes has keys that can play microtones when a "shift" key is pressed.
[edit] See also
[edit] References
- Bond, Ann (1997). A Guide to the Harpsichord. Amadeus Press. ISBN 1-57467-063-8.
[edit] External links
- Keyboard Magazine - features selections from magazine, along with multimedia examples.
- Synth Zone - a link directory of keyboard and synthesizer resources.
- Electronic Keyboard News - features news and reviews of keyboards, synthesizers and synth modules.
- Keyboard Chords - Chords for keyboards.
- MathPages - Mathematical discussion of the distribution of the keys
- Keyboard Quiz
- The Keyboard of a Harpsichord
