In music, a glissando (Italian: [ɡlisˈsando] ; plural: glissandi, abbreviated gliss.) is a glide from one pitch to another ( Play (help·info)). It is an Italianized musical term derived from the French glisser, "to glide". In some contexts, it is distinguished from the continuous portamento. Some colloquial equivalents are slide, sweep (referring to the "discrete glissando" effects on guitar and harp, respectively), bend, smear, rip (for a loud, violent gliss to the beginning of a note),  lip (in jazz terminology, when executed by changing one's embouchure on a wind instrument),  plop, or falling hail (a glissando on a harp using the back of the fingernails).  On wind instruments, a scoop is a glissando ascending to the onset of a note achieved entirely with the embouchure. 
Prescriptive attempts to distinguish the glissando from the portamento by limiting the former to the filling in of discrete intermediate pitches on instruments like the piano, harp, and fretted stringed instruments have run up against established usage of instruments like the trombone and timpani.  The latter could thus be thought of as capable of either "glissando" or "portamento", depending on whether the drum was rolled or not. The clarinet gesture that opens Rhapsody in Blue could likewise be thought of either way: it was originally planned as a glissando (Gershwin's score labels each individual note) but is in practice played as a portamento though described as a glissando. 
The glissando is indicated by following the initial note with a line, sometimes wavy, in the desired direction, often accompanied by the abbreviation gliss.. Occasionally, the desired notes are notated in the standard method (i.e. semiquavers) accompanied by the word 'glissando'.
On some instruments (e.g., piano, harp, xylophone), discrete tones are clearly audible when sliding. For example, on a keyboard, a player's fingernails can be made to slide across the white keys or over the black keys, producing either a C major scale or an F♯ major pentatonic scale, or their relative modes; by performing both at once, it is possible to produce a full chromatic scale. Pianists can also complete a glissando of two pitches an octave apart. Maurice Ravel used glissandi in many of his piano compositions, and "Alborada del Gracioso" contains notable piano glissando passages in thirds executed by the right hand. Rachmaninoff, Prokofiev, Liszt and Gershwin have all used glissandi for piano in notable compositions.
Organ players—particularly in contemporary music—sometimes employ an effect known as the palm glissando, where over the course of the glissando the flat of the hand is used to depress a wide area of keys simultaneously, resulting in a dramatic atonal sweep.[ citation needed ] A similar device on the piano are cluster-glissandos, used extensively by Karlheinz Stockhausen in Klavierstück X , and which "more than anything else, lend the work its unique aural flavour".  On a harp, the player can slide their finger across the strings, quickly playing the scale (or on pedal harp even arpeggios such as C♭-D-E♯-F-G♯-A♭-B). Wind, brass, and fretted-stringed-instrument players can perform an extremely rapid chromatic scale (e.g., sliding up or down a string quickly on a fretted instrument).
Arpeggio effects (likewise named glissando) are also obtained by bowed strings (playing harmonics) and brass, especially the horn. 
Musical instruments with continuously variable pitch can effect a portamento over a substantial range. These include unfretted stringed instruments (such as the violin, viola, cello and double bass, and fretless guitars), stringed instruments with a way of stretching the strings (such as the guitar, veena, or sitar), a fretted guitar or lap steel guitar when accompanied with the use of a slide, wind instruments without valves or stops (such as the trombone or slide whistle), timpani (kettledrums), electronic instruments (such as the theremin, the ondes Martenot, synthesizers and keytars), the water organ, and the human voice.
Other wind instruments can effect a similar limited slide by altering the lip pressure (on trumpet, for example) or a combination of embouchure and rolling the head joint (as on the flute), while others such as the clarinet can achieve this by slowly dragging fingers off tone holes or changing the oral cavity's resonance by manipulating tongue position, embouchure, and throat shaping. 
Many electric guitars are fitted with a tremolo arm which can produce either a portamento, a vibrato, or a combination of both (but not a true tremolo despite the name).
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A bent note is a musical note that is varied in pitch. With unfretted strings or other continuous-pitch instruments such as the trombone, or with the human voice, such variation is more properly described in terms of intonation. A note is commonly bent to a higher pitch on fretted instruments literally by bending the string with excess finger pressure, and to a lower pitch on harmonica (a free-reed aerophone) by altering the vocal tract to shift the resonance of the reed.  On brass instruments such as the trumpet, the note is bent by using the lip. "Indeterminately pitched instruments [such as unpitched percussion instruments and friction drum rolls]...produce a pitch or pitch spectrum that becomes higher with an increase of dynamic and lower with a decrease of dynamic." 
The bent note is commonly found in various forms of jazz, blues, and rock.
The bass guitar, electric bass or simply bass, is the lowest-pitched member of the string family. It is a plucked string instrument similar in appearance and construction to an electric or an acoustic guitar, but with a longer neck and scale length, and typically four to six strings or courses. Since the mid-1950s, the bass guitar has largely replaced the double bass in popular music.
The guitar is a fretted musical instrument that typically has six strings. It is usually held flat against the player's body and played by strumming or plucking the strings with the dominant hand, while simultaneously pressing selected strings against frets with the fingers of the opposite hand. A plectrum or individual finger picks may also be used to strike the strings. The sound of the guitar is projected either acoustically, by means of a resonant chamber on the instrument, or amplified by an electronic pickup and an amplifier.
String instruments, stringed instruments, or chordophones are musical instruments that produce sound from vibrating strings when a performer plays or sounds the strings in some manner.
An Aeolian harp is a musical instrument that is played by the wind. Named for Aeolus, the ancient Greek god of the wind, the traditional Aeolian harp is essentially a wooden box including a sounding board, with strings stretched lengthwise across two bridges. It is often placed in a slightly opened window where the wind can blow across the strings to produce sounds. The strings can be made of different materials and all be tuned to the same pitch, or identical strings can be tuned to different pitches. Besides being the only string instrument played solely by the wind, the Aeolian harp is also the only string instrument that plays solely harmonic frequencies. They are recognizable by the sound which is a result of this property, which has been described as eerie and ethereal.
In music, inharmonicity is the degree to which the frequencies of overtones depart from whole multiples of the fundamental frequency.
The fingerboard is an important component of most stringed instruments. It is a thin, long strip of material, usually wood, that is laminated to the front of the neck of an instrument. The strings run over the fingerboard, between the nut and bridge. To play the instrument, a musician presses strings down to the fingerboard to change the vibrating length, changing the pitch. This is called stopping the strings. Depending on the instrument and the style of music, the musician may pluck, strum or bow one or more strings with the hand that is not fretting the notes. On some instruments, notes can be sounded by the fretting hand alone, such as with hammer ons, an electric guitar technique.
A quarter tone is a pitch halfway between the usual notes of a chromatic scale or an interval about half as wide as a semitone, which itself is half a whole tone. Quarter tones divide the octave by 50 cents each, and have 24 different pitches.
In music, portamento is a pitch sliding from one note to another. The term originated from the Italian expression "portamento della voce", denoting from the beginning of the 17th century its use in vocal performances and emulation by members of the violin family and certain wind instruments, and is sometimes used interchangeably with anticipation. It is also applied to one type of glissando on, e.g., slide trombones, as well as to the "glide" function of steel guitars and synthesizers; in the latter it is often used to add a melancholic effect to the overall melody.
A multiphonic is an extended technique on a monophonic musical instrument in which several notes are produced at once. This includes wind, reed, and brass instruments, as well as the human voice. Multiphonic-like sounds on string instruments, both bowed and hammered, have also been called multiphonics, for lack of better terminology and scarcity of research.
The bowed string instrument musical technique bariolage involves "the alternation of notes on adjacent strings, one of which is usually open", exploiting "the individual timbre of the various strings." This may involve quick alternation between a static note and changing notes that form a melody either above or below the static note. The static note is usually an open string note, which creates a highly resonant sound. "Bariolage" is a nineteenth-century term for an eighteenth-century violin technique, the mechanics of which are not discussed by nineteenth-century writers. The usual bowing technique required, which also may be used separately from bariolage, is called ondulé in French or ondeggiando In Italian. However, it may also be executed with separate bow strokes. In bluegrass fiddling the technique is known as "cross-fingering". Perhaps looking back on what he considered an earlier, less advanced time, one pedagogue explains that
The name bariolage is given to the kind of passage which presents the appearance of disorder and oddness, in that the notes are not played in succession on the same string where one would expect this or when the notes e2, a1, d1, are played not on the same string but alternately with one stopped finger and the open string, or else finally when the open string is played in a position where a stopped note would normally be required.
In music, instrumentation is the particular combination of musical instruments employed in a composition, and the properties of those instruments individually. Instrumentation is sometimes used as a synonym for orchestration. This juxtaposition of the two terms was first made in 1843 by Hector Berlioz in his Grand traité d'instrumentation et d'orchestration modernes, and various attempts have since been made to differentiate them. Instrumentation is a more general term referring to an orchestrator's, composer's or arranger's selection of instruments in varying combinations, or even a choice made by the performers for a particular performance, as opposed to the narrower sense of orchestration, which is the act of scoring for orchestra a work originally written for a solo instrument or smaller group of instruments.
String piano is a term coined by American composer-theorist Henry Cowell (1897–1965) to collectively describe those pianistic extended techniques in which sound is produced by direct manipulation of the strings, instead of or in addition to striking the piano's keys. Pioneered by Cowell in the 1920s, such techniques are now often called upon in the works of avant-garde classical music composers.
Concertino is the diminutive of concerto, thus literally a small or short concerto.
A nut, on a stringed musical instrument, is a small piece of hard material that supports the strings at the end closest to the headstock or scroll. The nut marks one end of the vibrating length of each open string, sets the spacing of the strings across the neck, and usually holds the strings at the proper height from the fingerboard. Along with the bridge, the nut defines the scale lengths of the open strings.
In music, intonation is the pitch accuracy of a musician or musical instrument. Intonation may be flat, sharp, or both, successively or simultaneously.
Finger vibrato is vibrato produced on a string instrument by cyclic hand movements. Despite the name, normally the entire hand moves, and sometimes the entire upper arm. It can also refer to vibrato on some woodwind instruments, achieved by lowering one or more fingers over one of the uncovered holes in a trill-like manner. This flattens the note periodically creating the vibrato.
Guitar picking is a group of hand and finger techniques a guitarist uses to set guitar strings in motion to produce audible notes. These techniques involve plucking, strumming, brushing, etc. Picking can be done with:
On a string instrument, position is the relative location of the hand on the instrument's neck, indicated by ordinal numbers. Fingering, independent of position, is indicated by numbers, 1-4. Different positions on the same string are reached through shifting.
The veena, also spelled vina, comprises various chordophone instruments from the Indian subcontinent. Ancient musical instruments evolved into many variations, such as lutes, zithers and arched harps. The many regional designs have different names such as the Rudra veena, the Saraswati veena, the Vichitra veena and others.
falling hail: gliding in the center of the strings with the back of the fingernails. (C. Salzedo)