Musical Keyboard

Musical keyboard

A musical keyboard is the set of adjacent depressible levers or keys on a musical instrument. 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"

Description

The twelve notes of the Western musical scale are laid out with the lowest note on the left;[1] The longer keys (for the seven "natural" notes of the C major scale: C, D, E, F, G, A, B) jut forward. Because these keys were traditionally covered in ivory they are often called the white notes or white keys. The keys for the remaining five notes—which are not part of the C major scale—(i.e.,C♯/D♭, D♯/E♭, F♯/G♭, G♯/A♭, A♯/B♭) (see Sharp and Flat) are raised and shorter. Because these keys receive less wear, they are often made of black colored wood and called the black notes or black keys. The pattern repeats at the interval of an octave.

The arrangement of longer keys for C major with intervening, shorter keys for the intermediate semitones dates to the 15th century. Many keyboard instruments dating from before the nineteenth century, such as harpsichords and pipe organs, have a keyboard with the colours of the keys reversed: the white notes are made of ebony and the black notes are covered with softer white bone. A few electric and electronic instruments from the 1960s and subsequent decades have also done this; Vox's electronic organs of the 1960s, Farfisa's FAST portable organs, Hohner's Clavinet L, one version of Korg's Poly-800 synthesizer and Roland's digital harpsichords.

Some 1960s electronic organs used reverse colors or gray sharps or naturals to indicate the lower part(s) of a split keyboard: one divided into two parts, each of which produces a different registration or sound. Such keyboards allow melody and contrasting accompaniment to be played without the expense of a second manual and were a regular feature in Spanish and some English organs of the renaissance and baroque. The break was between middle C and C-sharp, or outside of Iberia between B and C. Broken keyboards reappeared in 1842 with the harmonium, the split occurring at E4/F4.

The reverse-colored keys on Hammond organs such as the B3, C3 and A100 are latch-style radio buttons for selecting pre-set sounds

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. (Digital systems allow shifting octaves, pitch, and "splitting" ranges dynamically, reducing the need for dedicated keys.) Organs normally have 61 keys per manual, though some spinet models have 44 or 49. An organ pedalboard is a keyboard with long pedals that 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 125 mm to as much as 170 mm. Modern piano keyboards ordinarily have an octave span of 164–165 mm; resulting in the width of black keys averaging 13.7 mm and white keys about 23.5 mm wide at the base, disregarding space between keys. 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 Reimann has promoted piano keyboards with narrower octave spans and has a U.S. patent on the apparatus and methods for modifying existing pianos to provide interchangeable keyboards of different sizes.[2]

There have been variations in the design of the keyboard to address technical and musical issues. The earliest designs of keyboards were based heavily on the notes used in Gregorian chant (the seven diatonic notes plus B-flat) and as such would often include B♭ and B♮ both as diatonic "white notes," with the B♮ at the leftmost side of the keyboard and the B♭ at the rightmost.

Source:https://en.wikipedia.org/wiki/Musical_keyboard