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| Developer(s) | Robert M. (Bob) Keller and others at Harvey Mudd College and elsewhere |
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| Initial release | 2006 March |
| Stable release | 10.2 / August 1, 2019 |
| Repository | |
| Operating system | Windows, macOS, Linux |
| Type | Scorewriter |
| License | GPL-2.0-or-later |
| Website | cs |
Impro-Visor is an educational tool for creating and playing a lead sheet, with a particular orientation toward representing jazz solos.
The philosophy of Impro-Visor is to provide a tool to help musicians construct jazz solos over chord progressions. It includes a database capability for creating, saving, and recalling licks, as well as a lick generation capability based on a user-modifiable grammar. More recent versions of Impro-Visor include auto-generated playback accompaniment in various styles, and a style extraction (from MIDI) capability. Most musical knowledge, including lick generation, database, lead sheets, styles, and other information, is represented as text files, permitting the tool to be customized.
Impro-Visor saves lead sheets in a textual notation, [1] and lead sheets may be created from that notation as well as by point-and-click. The notation was designed to be friendly to the jazz musician, by resembling directly what appears on the lead sheet staff. For example, the lead sheet fragment to the right, similar to that in article lead sheet , can be created by the following text:
C C7 | F |
c+2 bb2 bb8 a8 f2.
The reading of this text is: Chords C and C7 equally spaced in the first bar, and F in the second bar. A melody of c (the + means an octave above middle C, the 2 means a half-note), bb2, meaning a B-flat half-note, bb8, meaning a B-flat eighth-note, f2., meaning an F dotted half-note. Other meta-data can be supplied, such as for style specification, but is not required.
Impro-Visor categorizes tones that can be played over any chord into one of four categories. [2] This serves two purposes: (i) as visual feedback to the user, where each category is rendered as a different color, and (ii) as a basis for lick generation. The categories are:
The idea is that, aided by visual clues, the musician can learn to appreciate the degree to which a melody will be sonorous over a chord progression prior to hearing it.
Categories of notes discussed above are one of the key ingredients in automating the generation of melodies, which can be used by the musician in constructing solos. The other key ingredient is a context-free grammar having terminal symbols for each of the four categories, along with a few other terminal symbols for convenience. The grammar defines ways in which the melody space can be filled probabilistically by tones of various durations. By associating a probability with each grammar rule, the distribution of generated melodies can be controlled, for example to create melodies that are simple or complex, relatively consonant or dissonant, etc. The user indicates the chord progression, and the grammar drives the melody generation over that progression. [3]
The figure at the right demonstrates an example generated lick. This particular grammar is constructed so as not to produce any discordant notes (notes in the "other" category above), thus no red notes appear in the figure.
Version 4 added a feature for learning a grammar from a corpus of transcribed solos. [4] [5] The learned grammar loosely approximates the playing style of the soloist by creating abstract melodies from the solos, which can be re-instantiated into similar melodies through the grammar. Connections between learned abstract melodic fragments are represented as a Markov chain, which is encoded into the stochastic context-free grammar.
Impro-Visor automatically creates accompaniment, such as piano, bass, and drums, from the chord sequence on a leadsheet (a capability similar to, but currently not as full-featured as that of Band-in-a-Box). The style of accompaniment is derived from a set of pattern specifications using a textual notation similar to that for melodies. [6] For example, a ride cymbal pattern common to swing jazz would be notated as
x4 x8 x8 x4 x8 x8
with x4 signifying a quarter-note hit and x8 an eighth-note hit. The swung note aspect, wherein eighth-notes on the beat get approximately twice the value of the beat, is rendered automatically by a numeric swing parameter, such as .67, which indicates that the beat is divided as .67 + .33 = 1. A similar pattern notation is used for chord comping and bassline patterns. In the latter type of pattern, a note category coding scheme similar to that for the grammatical notation is used to provide probabilistic creation of basslines.
Impro-Visor analyzes jazz lead sheets to produce a roadmap of the tune. A roadmap is a sequence of bricks that represent harmonic idioms. [7] The nomenclature for this approach is derived from that of Conrad Cork [8] and John Elliott. [9]
Figured bass is musical notation in which numerals and symbols appear above or below a bass note. The numerals and symbols indicate intervals, chords, and non-chord tones that a musician playing piano, harpsichord, organ, or lute should play in relation to the bass note. Figured bass is closely associated with basso continuo: a historically improvised accompaniment used in almost all genres of music in the Baroque period of Classical music, though rarely in modern music. Figured bass is also known as thoroughbass.
Jazz guitar may refer to either a type of electric guitar or a guitar playing style in jazz, using electric amplification to increase the volume of acoustic guitars.
In music performances, rhythm guitar is a technique and role that performs a combination of two functions: to provide all or part of the rhythmic pulse in conjunction with other instruments from the rhythm section ; and to provide all or part of the harmony, i.e. the chords from a song's chord progression, where a chord is a group of notes played together. Therefore, the basic technique of rhythm guitar is to hold down a series of chords with the fretting hand while strumming or fingerpicking rhythmically with the other hand. More developed rhythm techniques include arpeggios, damping, riffs, chord solos, and complex strums.
Sheet music is a handwritten or printed form of musical notation that uses musical symbols to indicate the pitches, rhythms, or chords of a song or instrumental musical piece. Like its analogs – printed books or pamphlets in English, Arabic, or other languages – the medium of sheet music typically is paper. However, access to musical notation since the 1980s has included the presentation of musical notation on computer screens and the development of scorewriter computer programs that can notate a song or piece electronically, and, in some cases, "play back" the notated music using a synthesizer or virtual instruments.
The term blues scale refers to several different scales with differing numbers of pitches and related characteristics. A blues scale is often formed by the addition of an out-of-key "blue note" to an existing scale, notably the flat fifth addition to the minor pentatonic scale. However, the heptatonic blues scale can be considered a major scale with altered intervals.
In music, a chord is a group of three or more notes played simultaneously, typically consisting of a root note, a third, and a fifth. Chords are the building blocks of harmony and form the harmonic foundation of a piece of music. They can be major, minor, diminished, augmented, or extended, depending on the intervals between the notes and their arrangement. Chords provide the harmonic support and coloration that accompany melodies and contribute to the overall sound and mood of a musical composition. For many practical and theoretical purposes, arpeggios and other types of broken chords may also be considered as chords in the right musical context.
Accompaniment is the musical part which provides the rhythmic and/or harmonic support for the melody or main themes of a song or instrumental piece. There are many different styles and types of accompaniment in different genres and styles of music. In homophonic music, the main accompaniment approach used in popular music, a clear vocal melody is supported by subordinate chords. In popular music and traditional music, the accompaniment parts typically provide the "beat" for the music and outline the chord progression of the song or instrumental piece.
Lead guitar is a musical part for a guitar in which the guitarist plays melody lines, instrumental fill passages, guitar solos, and occasionally, some riffs and chords within a song structure. The lead is the featured guitar, which usually plays single-note-based lines or double-stops. In rock, heavy metal, blues, jazz, punk, fusion, some pop, and other music styles, lead guitar lines are often supported by a second guitarist who plays rhythm guitar, which consists of accompaniment chords and riffs.
In jazz, comping is the chords, rhythms, and countermelodies that keyboard players, guitar players, or drummers use to support a musician's improvised solo or melody lines. It is also the action of accompanying, and the left-hand part of a solo pianist.
A rhythm section is a group of musicians within a music ensemble or band that provides the underlying rhythm, harmony and pulse of the accompaniment, providing a rhythmic and harmonic reference and "beat" for the rest of the band. The rhythm section is often contrasted with the roles of other musicians in the band, such as the lead guitarist or lead vocals whose primary job is to carry the melody.
Basso continuo parts, almost universal in the Baroque era (1600–1750), provided the harmonic structure of the music by supplying a bassline and a chord progression. The phrase is often shortened to continuo, and the instrumentalists playing the continuo part are called the continuo group.
In popular music genres such as country, blues, jazz or rock music, a lick is "a stock pattern or phrase" consisting of a short series of notes used in solos and melodic lines and accompaniment. For musicians, learning a lick is usually a form of imitation. By imitating, musicians understand and analyze what others have done, allowing them to build a vocabulary of their own.
In music theory, chord substitution is the technique of using a chord in place of another in a progression of chords, or a chord progression. Much of the European classical repertoire and the vast majority of blues, jazz and rock music songs are based on chord progressions. "A chord substitution occurs when a chord is replaced by another that is made to function like the original. Usually substituted chords possess two pitches in common with the triad that they are replacing."
Jazz chords are chords, chord voicings and chord symbols that jazz musicians commonly use in composition, improvisation, and harmony. In jazz chords and theory, most triads that appear in lead sheets or fake books can have sevenths added to them, using the performer's discretion and ear. For example, if a tune is in the key of C, if there is a G chord, the chord-playing performer usually voices this chord as G7. While the notes of a G7 chord are G–B–D–F, jazz often omits the fifth of the chord—and even the root if playing in a group. However, not all jazz pianists leave out the root when they play voicings: Bud Powell, one of the best-known of the bebop pianists, and Horace Silver, whose quintet included many of jazz's biggest names from the 1950s to the 1970s, included the root note in their voicings.
A lead sheet or fake sheet is a form of musical notation that specifies the essential elements of a popular song: the melody, lyrics and harmony. The melody is written in modern Western music notation, the lyric is written as text below the staff and the harmony is specified with chord symbols above the staff.
Musical improvisation is the creative activity of immediate musical composition, which combines performance with communication of emotions and instrumental technique as well as spontaneous response to other musicians. Sometimes musical ideas in improvisation are spontaneous, but may be based on chord changes in classical music and many other kinds of music. One definition is a "performance given extempore without planning or preparation". Another definition is to "play or sing (music) extemporaneously, by inventing variations on a melody or creating new melodies, rhythms and harmonies". Encyclopædia Britannica defines it as "the extemporaneous composition or free performance of a musical passage, usually in a manner conforming to certain stylistic norms but unfettered by the prescriptive features of a specific musical text." Improvisation is often done within a pre-existing harmonic framework or chord progression. Improvisation is a major part of some types of 20th-century music, such as blues, rock music, jazz, and jazz fusion, in which instrumental performers improvise solos, melody lines and accompaniment parts.
A chord chart is a form of musical notation that describes the basic harmonic and rhythmic information for a song or tune. It is the most common form of notation used by professional session musicians playing jazz or popular music. It is intended primarily for a rhythm section. In these genres the musicians are expected to be able to improvise the individual notes used for the chords and the appropriate ornamentation, counter melody or bassline.
Jazz improvisation is the spontaneous creation of musical phrases and melodies within the framework of a jazz composition or performance. It involves spontaneously composing and performing melodies, rhythms, and harmonies, often drawing from a combination of musical scales, chord progressions, and personal expression. Improvisation is a key element of jazz music, allowing musicians to showcase their creativity, spontaneity, and individuality during performances.. It is one of the defining elements of jazz. Improvisation is composing on the spot, when a singer or instrumentalist invents melodies and lines over a chord progression played by rhythm section instruments and accompanied by drums. Although blues, rock, and other genres use improvisation, it is done over relatively simple chord progressions which often remain in one key.
In music, harmonization is the chordal accompaniment to a line or melody: "Using chords and melodies together, making harmony by stacking scale tones as triads".
Musicians use various kinds of chord names and symbols in different Contexts Chord notation is a system used to represent chords in written music or chord charts. It typically consists of one or more letters representing the root note of the chord, along with additional symbols or letters indicating the chord quality, extensions, and alterations. For example, the chord notation "CMA J7" represents a C major seventh chord, while "Dm7b5" represents a D minor seventh flat five chord. Chord notation allows musicians to quickly understand and play various chords in a piece of music without having to read the full musical score. to represent musical chords. In most genres of popular music, including jazz, pop, and rock, a chord name and its corresponding symbol typically indicate one or more of the following:
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