Editing Music theory (section)

==Fundamentals of music==
{{Main|Aspect of music}}
Music is composed of [[aural]] phenomena; "music theory" considers how those phenomena apply in music. Music theory considers melody, rhythm, counterpoint, harmony, form, tonal systems, scales, tuning, intervals, consonance, dissonance, durational proportions, the acoustics of pitch systems, composition, performance, orchestration, ornamentation, improvisation, electronic sound production, etc.{{sfn|Palisca and Bent|n.d.}}

===Pitch===
{{Main|Pitch (music)}}
[[File:Middle C.png|thumb|Middle C (261.626&nbsp;Hz)[[File:Middle C.mid]]]]
Pitch is the lowness or highness of a [[Musical tone|tone]], for example the difference between [[middle C]] and a higher C. The frequency of the sound waves producing a pitch can be measured precisely, but the perception of pitch is more complex because single notes from natural sources are usually a complex mix of many frequencies. Accordingly, theorists often describe pitch as a subjective sensation rather than an objective measurement of sound.{{sfn|Hartmann|2005|loc={{Page needed|date=August 2014}}}}

Specific frequencies are often assigned letter names. Today most orchestras assign [[concert A]] (the A above [[middle C]] on the piano) to the frequency of 440&nbsp;Hz. This assignment is somewhat arbitrary; for example, in 1859 France, the same A was tuned to 435&nbsp;Hz. Such differences can have a noticeable effect on the timbre of instruments and other phenomena. Thus, in [[historically informed performance]] of older music, tuning is often set to match the tuning used in the period when it was written. Additionally, many cultures do not attempt to standardize pitch, often considering that it should be allowed to vary depending on genre, style, mood, etc.

The difference in pitch between two notes is called an [[interval (music)|interval]]. The most basic interval is the [[unison]], which is simply two notes of the same pitch. The [[octave]] interval is two pitches that are either double or half the frequency of one another. The unique characteristics of octaves gave rise to the concept of [[pitch class]]: pitches of the same letter name that occur in different octaves may be grouped into a single "class" by ignoring the difference in octave. For example, a high C and a low C are members of the same pitch class—the class that contains all C's.{{Sfn|Bartlette and Laitz|2010|loc={{Page needed|date=October 2014}}}}

[[Musical tuning]] systems, or temperaments, determine the precise size of intervals. Tuning systems vary widely within and between world cultures. In [[Western culture]], there have long been several competing tuning systems, all with different qualities. Internationally, the system known as [[equal temperament]] is most commonly used today because it is considered the most satisfactory compromise that allows instruments of fixed tuning (e.g. the piano) to sound acceptably in tune in all keys.

===Scales and modes===
{{Main|Musical scale| Musical mode}}
[[File:C major scale.png|thumb|upright=1.3|A pattern of whole and half steps in the Ionian mode or major scale on C[[File:Ionian mode C.mid]]]]
Notes can be arranged in a variety of [[scale (music)|scale]]s and [[musical mode|modes]]. Western music theory generally divides the octave into a series of twelve pitches, called a [[chromatic scale]], within which the interval between adjacent tones is called a [[semitone]], or half step. Selecting tones from this set of 12 and arranging them in patterns of semitones and whole tones creates other scales.{{sfn|Touma|1996|loc={{Page needed|date=August 2014}}}}

The most commonly encountered scales are the seven-toned [[major scale|major]], the [[harmonic minor]], the [[melodic minor]], and the [[natural minor]]. Other examples of scales are the [[octatonic scale]] and the [[pentatonic]] or five-tone scale, which is common in [[folk music]] and [[blues]]. Non-Western cultures often use scales that do not correspond with an equally divided twelve-tone division of the octave. For example, classical [[Ottoman classical music|Ottoman]], [[Persian classical music|Persian]], [[Indian classical music|Indian]] and [[Arabic music|Arabic]] musical systems often make use of multiples of quarter tones (half the size of a semitone, as the name indicates), for instance in 'neutral' seconds (three quarter tones) or 'neutral' thirds (seven quarter tones)—they do not normally use the quarter tone itself as a direct interval.{{sfn|Touma|1996|loc={{Page needed|date=August 2014}}}}

In traditional Western notation, the scale used for a composition is usually indicated by a [[key signature]] at the beginning to designate the pitches that make up that scale. As the music progresses, the pitches used may change and introduce a different scale. Music can be [[Transposition (music)|transposed]] from one scale to another for various purposes, often to accommodate the range of a vocalist. Such transposition raises or lowers the overall pitch range, but preserves the intervallic relationships of the original scale. For example, transposition from the key of C major to D major raises all pitches of the scale of C major equally by a [[whole tone]]. Since the interval relationships remain unchanged, transposition may be unnoticed by a listener, however other qualities may change noticeably because transposition changes the relationship of the overall pitch [[range (music)|range]] compared to the range of the instruments or voices that perform the music. This often affects the music's overall sound, as well as having technical implications for the performers.{{sfn|Forsyth|1935|loc=73–74}}

The interrelationship of the keys most commonly used in Western tonal music is conveniently shown by the [[circle of fifths]]. Unique key signatures are also sometimes devised for a particular composition. During the Baroque period, emotional associations with specific keys, known as the [[doctrine of the affections]], were an important topic in music theory, but the unique tonal colorings of keys that gave rise to that doctrine were largely erased with the adoption of equal temperament. However, many musicians continue to feel that certain keys are more appropriate to certain emotions than others. [[Indian classical music]] theory continues to strongly associate keys with emotional states, times of day, and other extra-musical concepts and notably, does not employ equal temperament.

===Consonance and dissonance===
{{Main|Consonance and dissonance}}
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[[Consonance and dissonance]] are subjective qualities of the sonority of intervals that vary widely in different cultures and over the ages. Consonance (or concord) is the quality of an interval or chord that seems stable and complete in itself. Dissonance (or discord) is the opposite in that it feels incomplete and "wants to" resolve to a consonant interval. Dissonant intervals seem to clash. Consonant intervals seem to sound comfortable together. Commonly, perfect fourths, fifths, and octaves and all major and minor thirds and sixths are considered consonant. All others are dissonant to a greater or lesser degree.{{sfn|Latham|2002|loc={{Page needed|date=August 2014}}}}

Context and many other aspects can affect apparent dissonance and consonance. For example, in a Debussy prelude, a major second may sound stable and consonant, while the same interval may sound dissonant in a Bach fugue. In the [[Common practice period|Common practice era]], the perfect fourth is considered dissonant when not supported by a lower third or fifth. Since the early 20th century, [[Arnold Schoenberg]]'s concept of "emancipated" dissonance, in which traditionally dissonant intervals can be treated as "higher," more remote consonances, has become more widely accepted.{{sfn|Latham|2002|loc={{Page needed|date=August 2014}}<!--Better would be the title of the article in this dictionary, added to the entry in the list of references, in which case a page number would be superfluous.-->}}

===Rhythm===
{{Main|Rhythm}}
[[File:Metric levels.svg|thumb|upright=1.3|[[Metric level]]s: beat level shown in middle with division levels above and multiple levels below]]
Rhythm is produced by the sequential arrangement of sounds and silences in time. [[Metre (music)|Meter]] measures music in regular pulse groupings, called [[Bar (music)|measures or bars]]. The [[time signature]] or meter signature specifies how many beats are in a measure, and which value of written note is counted or felt as a single beat.

Through increased stress, or variations in duration or articulation, particular tones may be accented. There are conventions in most musical traditions for regular and hierarchical accentuation of beats to reinforce a given meter. [[Syncopation|Syncopated]] rhythms contradict those conventions by accenting unexpected parts of the beat.<ref>{{cite book|chapter=Syncopation|title=The Oxford Dictionary of Music |url=https://www.oxfordreference.com/display/10.1093/acref/9780199579037.001.0001/acref-9780199579037-e-6605?rskey=S0uJUr&result=1 |quote=Syncopation is achieved by accenting a weak instead of a strong beat, by putting rests on strong beats, by holding on over strong beats, and by introducing a sudden change of time‐signature.|isbn=978-0199578108|publisher=Oxford University Press|year= 2013}}</ref> Playing simultaneous rhythms in more than one time signature is called [[polyrhythm]].<ref>{{cite web|title=Polyrhythm|url=http://www.oxfordmusiconline.com/subscriber/article/grove/music/22059|website=Grove Music Online |publisher= Oxford University Press|access-date=11 August 2017|quote=The superposition of different rhythms or metres.}}</ref>

In recent years, rhythm and meter have become an important area of research among music scholars. The most highly cited of these recent scholars are [[Maury Yeston]],{{sfn|Yeston|1976}} [[Fred Lerdahl]] and [[Ray Jackendoff]],{{sfn|Lerdahl and Jackendoff|1985}} [[Jonathan Kramer]],{{sfn|Kramer|1988}} and Justin London.{{sfn|London|2004}}

===Melody===
{{Main|Melody}}
[[File:Pop Goes the Weasel melody.PNG|thumb|upright=1.3|"[[Pop Goes the Weasel]]" melody{{sfn|Kliewer|1975|loc={{Page needed|date=September 2012}}}}[[File:Pop Goes the Weasel.ogg]]]]
A [[melody]] is a group of musical sounds in agreeable succession or arrangement.<ref>{{Cite web |title=Definition of melody {{!}} Dictionary.com |url=https://www.dictionary.com/browse/melody |access-date=2023-01-11 |website=www.dictionary.com |language=en}}</ref> Because melody is such a prominent aspect in so much music, its construction and other qualities are a primary interest of music theory.

The basic elements of melody are pitch, duration, rhythm, and tempo. The tones of a melody are usually drawn from pitch systems such as [[Musical scale|scales]] or [[Musical mode|modes]]. Melody may consist, to increasing degree, of the figure, motive, semi-phrase, antecedent and consequent phrase, and period or sentence. The period may be considered the complete melody, however some examples combine two periods, or use other combinations of constituents to create larger form melodies.{{sfn|Stein|1979|loc=3–47}}

{{Clear}}

===Chord===
{{Main|Chord (music)}}
[[File:C triad.svg|thumb|upright=0.7|C major triad represented in [[staff notation]].<br />{{Audio|Just major triad on C.mid|Play}} in [[just intonation]]<br />{{Audio|Major triad on C.mid|Play}} in [[Equal temperament]]<br />{{Audio|Quarter-comma meantone major chord on C.mid|Play}} in [[Meantone temperament|1/4-comma meantone]]<br />{{Audio|Young temperament major chord on C.mid|Play}} in [[Young temperament]]<br />{{Audio|Pythagorean major chord on C.mid|Play}} in [[Pythagorean tuning]] ]]
A chord, in music, is any [[harmony|harmonic]] set of three or more [[Musical note|note]]s that is heard as if sounding [[Simultaneity (music)|simultaneously]].{{sfn|Benward and Saker|2003}}{{rp|pp. 67, 359|quote=A chord is a harmonic unit with at least three different tones sounding simultaneously." "A combination of three or more pitches sounding at the same time.}}{{sfn|Károlyi|1965|}}{{rp|p. 63|quote=Two or more notes sounding simultaneously are known as a chord.}} These need not actually be played together: [[arpeggio]]s and broken chords may, for many practical and theoretical purposes, constitute chords. Chords and [[Chord progression|sequences of chords]] are frequently used in modern Western, West African,{{sfn|Mitchell|2008}} and Oceanian{{sfn|Linkels|n.d.|loc={{Page needed|date=July 2015}}<!--Specific page citation within this twelve-page article needed.-->}} music, whereas they are absent from the music of many other parts of the world.{{sfn|Malm|1996}}{{rp|p. 15|quote=Indeed this harmonic orientation is one of the major differences between Western and much non-Western music.}}

The most frequently encountered chords are [[Triad (music)|triads]], so called because they consist of three distinct notes: further notes may be added to give [[seventh chord]]s, [[extended chord]]s, or [[added tone chord]]s. The most [[Common chord (music)|common chord]]s are the ''[[major chord|major]]'' and ''[[minor chord|minor]] [[Triad (music)|triads]]'' and then the ''[[augmented triad|augmented]]'' and ''[[diminished triad|diminished]] [[Triad (music)|triads]]''. The descriptions ''major'', ''minor'', ''augmented'', and ''diminished'' are sometimes referred to collectively as chordal ''quality''. Chords are also commonly classed by their [[root (chord)|root]] note—so, for instance, the chord '''C''' major may be described as a triad of major quality built on the note '''C'''. Chords may also be classified by [[Inverted chord|inversion]], the order in which the notes are stacked.

A series of chords is called a [[chord progression]]. Although any chord may in principle be followed by any other chord, certain patterns of chords have been accepted as establishing [[Key (music)|key]] in [[Common practice harmony|common-practice harmony]]. To describe this, chords are numbered, using [[Roman numerals]] (upward from the key-note),{{sfn|Schoenberg|1983|loc=1–2}} per their [[diatonic function]]. Common ways of [[#Notation|notating or representing chords]]{{sfn|Benward and Saker|2003|loc=77}} in western music other than conventional [[staff notation]] include [[Roman numerals#Music theory|Roman numerals]], [[figured bass]] (much used in the [[Baroque music|Baroque era]]), [[chord letter]]s (sometimes used in modern [[musicology]]), and various systems of [[chord chart]]s typically found in the [[lead sheet]]s used in [[Chord names and symbols (popular music)|popular music]] to lay out the sequence of chords so that the musician may play accompaniment chords or improvise a solo.

===Harmony===
{{Main|Harmony}}
[[File:US Navy 080615-N-7656R-003 Navy Band Northwest's Barbershop Quartet win the hearts of the audience with a John Philip Sousa rendition of.jpg|thumb|[[Barbershop quartet]]s, such as this US Navy group, sing 4-part pieces, made up of a melody line (normally the second-highest voice, called the "lead") and 3 harmony parts.]]
In music, harmony is the use of simultaneous [[pitch (music)|pitches]] ([[timbre|tones]], [[note (music)|notes]]), or [[chord (music)|chords]].{{sfn|Malm|1996|}}{{rp|p. 15|quote=Homophonic texture... is more common in Western music, where tunes are often built on chords (harmonies) that move in progressions. Indeed this harmonic orientation is one of the major differences between Western and much non-Western music.}} The study of harmony involves chords and their construction and [[chord progression]]s and the principles of connection that govern them.{{sfn|Dahlhaus|2009}} Harmony is often said to refer to the "vertical" aspect of music, as distinguished from [[melody|melodic line]], or the "horizontal" aspect.{{sfn|Jamini|2005|loc=147}} [[Counterpoint]], which refers to the interweaving of melodic lines, and [[polyphony]], which refers to the relationship of separate independent voices, is thus sometimes distinguished from harmony.<ref>{{cite web |url=http://sites.fas.harvard.edu/~lab51/theory/html/struct8.html |title=Pitch Structure: Harmony and Counterpoint |author=Faculty of Arts & Sciences |work=Theory of Music – Pitch Structure: The Chromatic Scale |publisher=Harvard University |access-date=2 October 2020 }}</ref>

In [[popular harmony|popular]] and [[jazz harmony]], chords are named by their [[root (chord)|root]] plus various terms and characters indicating their qualities. For example, a [[lead sheet]] may indicate chords such as C major, D minor, and G dominant seventh. In many types of music, notably Baroque, Romantic, modern, and jazz, chords are often augmented with "tensions". A tension is an additional chord member that creates a relatively [[Consonance and dissonance|dissonant interval]] in relation to the bass. It is part of a chord, but is not one of the chord tones (1 3 5 7). Typically, in the classical [[common practice period]] a dissonant chord (chord with tension) "resolves" to a consonant chord. [[Harmonization]] usually sounds pleasant to the ear when there is a balance between the consonant and dissonant sounds. In simple words, that occurs when there is a balance between "tense" and "relaxed" moments.<ref>{{cite web|url=https://shodhganga.inflibnet.ac.in/bitstream/10603/14206/6/06_chapter%202.pdf|title=Chapter 2 Elements and concepts of music (With reference to Hindustani and Jazz music)|website=Shodhganga.inflibnet.ac.in|access-date=3 March 2022}}</ref>{{unreliable source?|date=November 2019|reason=Self-contradictory, self-published?}}

===Timbre===
{{Main|Timbre}}
[[File:9577 Guitarz1970 Clean E9 Guitar Chord (Mike Tribulas).jpg|thumb|right|[[Spectrogram]] of the first second of an E9 chord played on a Fender Stratocaster guitar with noiseless pickups. Below is the E9 chord audio:
[[File:9577 Guitarz1970 Clean E9 Guitar Chord (Mike Tribulas).ogg]] ]]Timbre, sometimes called "color", or "tone color," is the principal phenomenon that allows us to distinguish one instrument from another when both play at the same pitch and volume, a quality of a voice or instrument often described in terms like bright, dull, shrill, etc. It is of considerable interest in music theory, especially because it is one component of music that has as yet, no standardized nomenclature. It has been called "... the psychoacoustician's multidimensional waste-basket category for everything that cannot be labeled pitch or loudness,"{{sfn|McAdams and Bregman|1979|loc=34}} but can be accurately described and analyzed by [[Fourier analysis]] and other methods{{sfn|Mannell|n.d.}} because it results from the combination of all sound [[Audio frequency|frequencies]], attack and release envelopes, and other qualities that a tone comprises.

[[Timbre]] is principally determined by two things: (1) the relative balance of [[overtones]] produced by a given instrument due its construction (e.g. shape, material), and (2) the [[Envelope (waves)|envelope]] of the sound (including changes in the overtone structure over time). Timbre varies widely between different instruments, voices, and to lesser degree, between instruments of the same type due to variations in their construction, and significantly, the performer's technique. The timbre of most instruments can be changed by employing different techniques while playing. For example, the timbre of a trumpet changes when a mute is inserted into the bell, the player changes their embouchure, or volume.{{Citation needed|date=July 2015}}

A voice can change its timbre by the way the performer manipulates their vocal apparatus, (e.g. the shape of the vocal cavity or mouth). Musical notation frequently specifies alteration in timbre by changes in sounding technique, volume, accent, and other means. These are indicated variously by symbolic and verbal instruction. For example, the word ''dolce'' (sweetly) indicates a non-specific, but commonly understood soft and "sweet" timbre. ''Sul tasto'' instructs a string player to bow near or over the fingerboard to produce a less brilliant sound. ''Cuivre'' instructs a brass player to produce a forced and stridently brassy sound. Accent symbols like ''marcato'' (^) and dynamic indications (''pp'') can also indicate changes in timbre.<ref>{{Cite web|url=https://www.sheffield.k12.oh.us/Downloads/IMG.pdf|title=How Loud? How Soft?|website=Sheffield-Sheffield Lake City Schools}}</ref>

====Dynamics====
{{Unreferenced section|date=July 2015}}
{{Main|Dynamics (music)}}
[[File:Music hairpins.svg|thumb|upright=1.3|Illustration of hairpins in musical notation]]
In music, "[[dynamics (music)|dynamics]]" normally refers to variations of intensity or volume, as may be measured by physicists and audio engineers in [[decibels]] or [[phon]]s. In music notation, however, dynamics are not treated as absolute values, but as relative ones. Because they are usually measured subjectively, there are factors besides amplitude that affect the performance or perception of intensity, such as timbre, vibrato, and articulation.

The conventional indications of dynamics are abbreviations for Italian words like ''forte'' ('''''f''''') for loud and ''piano'' ('''''p''''') for soft. These two basic notations are modified by indications including ''mezzo piano'' ('''''mp''''') for moderately soft (literally "half soft") and ''mezzo forte'' ('''''mf''''') for moderately loud, ''sforzando'' or ''sforzato'' ('''''sfz''''') for a surging or "pushed" attack, or ''fortepiano'' ('''''fp''''') for a loud attack with a sudden decrease to a soft level. The full span of these markings usually range from a nearly inaudible ''pianissississimo'' ('''''pppp''''') to a loud-as-possible ''fortissississimo'' ('''''ffff''''').

Greater extremes of '''''pppppp''''' and '''''fffff''''' and nuances such as '''''p+''''' or ''più piano'' are sometimes found. Other systems of indicating volume are also used in both notation and analysis: dB (decibels), numerical scales, colored or different sized notes, words in languages other than Italian, and symbols such as those for progressively increasing volume (''crescendo'') or decreasing volume (''diminuendo'' or ''decrescendo''), often called "[[Dynamics (music)|hairpins]]" when indicated with diverging or converging lines as shown in the graphic above.

====Articulation====
{{Unreferenced section|date=July 2015}}
{{Main|Articulation (music)}}
[[File:Notation accents1.png|thumb|upright=1.4|Examples of articulation marks. From left to right: [[staccato]], [[staccatissimo]], [[martellato]], [[Accent (music)|accent]], [[tenuto]].]]
Articulation is the way the performer sounds notes. For example, ''[[staccato]]'' is the shortening of duration compared to the written note value, ''[[legato]]'' performs the notes in a smoothly joined sequence with no separation. Articulation is often described rather than quantified, therefore there is room to interpret how to execute precisely each articulation.

For example, ''staccato'' is often referred to as "separated" or "detached" rather than having a defined or numbered amount by which to reduce the notated duration. Violin players use a variety of techniques to perform different qualities of ''staccato.'' The manner in which a performer decides to execute a given articulation is usually based on the context of the piece or phrase, but many articulation symbols and verbal instructions depend on the instrument and musical period (e.g. viol, wind; classical, baroque; etc.).

There is a set of articulations that most instruments and voices perform in common. They are—from long to short: ''legato'' (smooth, connected); ''[[tenuto]]'' (pressed or played to full notated duration); ''[[marcato]]'' (accented and detached); ''staccato'' ("separated", "detached"); ''[[martelé (bowstroke)|martelé]]'' (heavily accented or "hammered").{{Contradictory inline|date=March 2020|reason=The accompanying illustration names "staccato", "tenuto", and three other articulations not listed here. Are these synonyms and, if so, which are synonyms of which? Neither list is cited to a reliable source.}} Many of these can be combined to create certain "in-between" articulations. For example, ''[[portato]]'' is the combination of ''tenuto'' and ''staccato''. Some instruments have unique methods by which to produce sounds, such as ''[[spiccato]]'' for bowed strings, where the bow bounces off the string.

===Texture===
{{Main|Musical texture}}
[[File:Sousa - "Washington Post March," m. 1-7.png|thumb|upright=1.2|Introduction to [[John Philip Sousa|Sousa]]'s "[[The Washington Post (march)|Washington Post March]]," mm. 1–7 features [[octave doubling]]{{Sfn|Benward and Saker|2003|p=133}} and a homorhythmic texture[[File:Sousa - "Washington Post March," m. 1-7.mid]]]]
In music, texture is how the [[melody|melodic]], [[rhythm]]ic, and [[harmony|harmonic]] materials are combined in a [[musical composition|composition]], thus determining the overall quality of the sound in a piece. Texture is often described in regard to the density, or thickness, and [[range (music)|range]], or width, between lowest and highest pitches, in relative terms as well as more specifically distinguished according to the number of voices, or parts, and the relationship between these voices. For example, a thick texture contains many "layers" of instruments. One of these layers could be a string section, or another brass.

The thickness also is affected by the number and the richness of the instruments playing the piece. The thickness varies from light to thick. A lightly textured piece will have light, sparse scoring. A thickly or heavily textured piece will be scored for many instruments. A piece's texture may be affected by the number and character of parts playing at once, the [[timbre]] of the instruments or voices playing these parts and the harmony, [[tempo]], and rhythms used.{{sfn|Benward and Saker|2003|loc={{Page needed|date=July 2015}}}} The types categorized by number and relationship of parts are analyzed and determined through the labeling of primary textural elements: primary melody, secondary melody, parallel supporting melody, static support, harmonic support, rhythmic support, and harmonic and rhythmic support.{{sfn|Isaac and Russell|2003|loc=136}}{{incomplete short citation|date=December 2021}}

Common types included [[Monophony|monophonic]] texture (a single melodic voice, such as a piece for solo soprano or solo flute), biphonic texture (two melodic voices, such as a duo for bassoon and flute in which the bassoon plays a drone note and the flute plays the melody), [[polyphonic]] texture and [[Homophony|homophonic]] texture (chords accompanying a melody).{{Citation needed|date=August 2015}}<!--Especially for the drone accompaniment, which is usually regarded as a type of monophony.-->

===Form or structure===
[[File:Canon example.png|thumb|A musical [[canon (music)|canon]]. ''Encyclopaedia Britannica'' calls a "canon" both a compositional technique and a musical form.<ref>{{Britannica URL|art/canon-music|title=Canon: music}}</ref>]]
{{Main|Musical form}}
The term musical form (or musical architecture) refers to the overall structure or plan of a piece of music, and it describes the layout of a composition as divided into sections.{{sfn|Brandt|2007}} In the tenth edition of ''[[The Oxford Companion to Music]]'', [[Percy Scholes]] defines musical form as "a series of strategies designed to find a successful mean between the opposite extremes of unrelieved repetition and unrelieved alteration."{{sfn|Scholes|1977}} According to [[Richard Middleton (musicologist)|Richard Middleton]], musical form is "the shape or structure of the work." He describes it through difference: the distance moved from a [[Repetition (music)|repeat]]; the latter being the smallest difference. Difference is quantitative and qualitative: ''how far'', and ''of what type'', different. In many cases, form depends on statement and [[Restatement (music)|restatement]], unity and variety, and [[contrast (music)|contrast]] and connection.{{sfn|Middleton|1999|loc={{Page needed|date=July 2015}}}}

===Expression===
{{Main|Musical expression}}
[[File:1Francisco20violinista.jpg|thumb|right|220px|A violinist performing]]
Musical expression is the art of playing or singing music with emotional communication. The elements of music that comprise expression include dynamic indications, such as forte or piano, [[Musical phrasing|phrasing]], differing qualities of timbre and articulation, color, intensity, energy and excitement. All of these devices can be incorporated by the performer. A performer aims to elicit responses of sympathetic feeling in the audience, and to excite, calm or otherwise sway the audience's physical and emotional responses. Musical expression is sometimes thought to be produced by a combination of other parameters, and sometimes described as a transcendent quality that is more than the sum of measurable quantities such as pitch or duration.

Expression on instruments can be closely related to the role of the breath in singing, and the voice's natural ability to express feelings, sentiment and deep emotions.{{clarify|date=July 2015}}<!--Does this mean that keyboard and stringed instruments are essentially inexpressive?--> Whether these can somehow be categorized is perhaps the realm of academics, who view expression as an element of musical performance that embodies a consistently recognizable [[emotion]], ideally causing a [[emotional contagion|sympathetic emotional response]] in its listeners.{{sfn|London|n.d.}} The emotional content of musical expression is distinct from the emotional content of specific sounds (e.g., a startlingly-loud 'bang') and of learned associations (e.g., a [[national anthem]]), but can rarely be completely separated from its context.{{Citation needed|date=July 2015}}

The components of musical expression continue to be the subject of extensive and unresolved dispute.{{sfn|Avison|1752|loc={{Page needed|date=July 2015}}<!--Where does Avison say there is a continuing and unresolved dispute?-->}}{{sfn|Christiani|1885|loc={{Page needed|date=July 2015}}<!--Where does Christiani say there is a continuing and unresolved dispute?-->}}{{sfn|Lussy|1892|loc={{Page needed|date=July 2015}}<!--On what page(s) does Lussy state there is an extensive and unresolved dispute, or indeed that there is any dispute at all?-->}}{{sfn|Darwin|1913|loc={{Page needed|date=July 2015}}<!--Where does Darwin state that there is a continuing and unresolved dispute?-->}}{{sfn|Sorantin|1932|loc={{Page needed|date=July 2015}}<!--On what page(s) does Sorantin contend that there is an extensive and unresolved dispute on thesubject?-->}}{{sfn|Davies|1994|loc={{Page needed|date=July 2015}}<!--On what page does Davies say the components of expression continue to be subject to unresolved dispute? He mentions particular disputes on pp. 105, 136, 213, and 364, but characterises none of them as "extensive", nor does he say whether these disputes are resolved or not.-->}}

===Notation===
{{Main|Musical notation|Sheet music}}
[[File:Tibetanmusicalscore.jpg|thumb|[[Tibet]]an musical score from the 19th century]]
Musical notation is the written or symbolized representation of music. This is most often achieved by the use of commonly understood graphic symbols and written verbal instructions and their abbreviations. There are many systems of music notation from different cultures and different ages. Traditional Western notation evolved during the Middle Ages and remains an area of experimentation and innovation.{{Sfnm|Read|1969|1loc={{Page needed|date=August 2014}}|Stone|1980|2loc={{Page needed|date=August 2014}}}} In the 2000s, computer [[file formats]] have become important as well.{{sfn|Castan|2009}} Spoken language and [[Kodály Method#Hand signs|hand signs]] are also used to symbolically represent music, primarily in teaching.

In standard Western music notation, tones are represented graphically by symbols (notes) placed on a [[Staff (music)|staff]] or staves, the vertical axis corresponding to pitch and the horizontal axis corresponding to time. Note head shapes, stems, flags, ties and dots are used to indicate duration. Additional symbols indicate keys, dynamics, accents, rests, etc. Verbal instructions from the conductor are often used to indicate tempo, technique, and other aspects.

In Western music, a range of different music notation systems are used. In Western Classical music, conductors use printed scores that show all of the instruments' parts and orchestra members read parts with their musical lines written out. In popular styles of music, much less of the music may be notated. A rock band may go into a recording session with just a handwritten [[chord chart]] indicating the song's [[chord progression]] using chord names (e.g., C major, D minor, G7, etc.). All of the chord voicings, rhythms and accompaniment figures are improvised by the band members.