In
music theory, the key of a piece is the group of pitches, or
scale, that forms the basis of a
musical composition in
classical, Western art, and Western pop music.
The group features a ''
tonic note'' and its corresponding ''
chords'', also called a ''tonic'' or ''tonic chord'', which provides a subjective sense of arrival and rest, and also has a unique relationship to the other pitches of the same group, their corresponding chords, and pitches and chords outside the group. Notes and chords other than the tonic in a piece create varying degrees of tension,
resolved when the tonic note or chord returns.
The key may be in the
major or minor mode, though musicians assume major when this is not specified, e.g., "This piece is in C" implies that the key of the song is C major.
Popular songs
Popular music is music with wide appeal that is typically distributed to large audiences through the music industry. These forms and styles can be enjoyed and performed by people with little or no musical training.Popular Music. (2015). ''Funk ...
are usually in a key, and so is classical music during the
common practice period, around 1650–1900. Longer pieces in the classical repertoire may have sections in
contrasting key
Contrast may refer to:
Science
* Contrast (vision), the contradiction in form, colour and light between parts of an image
* Contrast (statistics), a combination of averages whose coefficients add up to zero, or the difference between two means
* ...
s.
Overview
Methods that establish the key for a particular piece can be complicated to explain and vary over music history. However, the chords most often used in a piece in a particular key are those that contain the notes in the corresponding
scale, and conventional
progressions of these chords, particularly
cadences, orient the listener around the tonic.
The
key signature is not always a reliable guide to the key of a written piece. It does not discriminate between a major key and its
relative minor; the piece may
modulate to a different key; if the modulation is brief, it may not involve a change of key signature, being indicated instead with
accidentals. Occasionally, a piece in a
mode
Mode ( la, modus meaning "manner, tune, measure, due measure, rhythm, melody") may refer to:
Arts and entertainment
* '' MO''D''E (magazine)'', a defunct U.S. women's fashion magazine
* ''Mode'' magazine, a fictional fashion magazine which is ...
such as
Mixolydian or
Dorian is written with a major or minor key signature appropriate to the tonic, and accidentals throughout the piece.
Pieces in modes not corresponding to major or minor keys may sometimes be referred to as being in the key of the tonic. A piece using some other type of
harmony, resolving e.g. to A, might be described as "in A" to indicate that A is the
tonal center of the piece.
An instrument is "in a key", an unrelated usage that means the pitches considered "natural" for that instrument. For example, modern
trumpets are usually in the key of B, since the notes produced without using the valves correspond to the
harmonic series whose fundamental pitch is B. (Such instruments are called ''
transposing'' when their written notes differ from
concert pitch.)
A key relationship is the relationship between keys, measured by
common tone and nearness on the
circle of fifths. See
closely related key.
Keys and tonality
The key usually identifies the
tonic note and/or chord: the note and/or
major or
minor triad
Triad or triade may refer to:
* a group of three
Businesses and organisations
* Triad (American fraternities), certain historic groupings of seminal college fraternities in North America
* Triad (organized crime), a Chinese transnational orga ...
that represents the final point of rest for a piece, or the focal point of a section. Though the key of a piece may be named in the title (e.g., Symphony in C major), or inferred from the
key signature, the establishment of key is brought about via
functional harmony, a sequence of chords leading to one or more
cadences, and/or melodic motion (such as movement from the leading-tone to the tonic). For example, the key of G includes the following pitches: G, A, B, C, D, E, and F; and its corresponding tonic chord is G—B—D. Most often at the beginning and end of traditional pieces during the common practice period, the tonic, sometimes with its corresponding tonic chord, begins and ends a piece in a designated key. A key may be major or minor. Music can be described as being in the
Dorian mode, or
Phrygian, etc., and is thus usually thought of as in a specific
mode
Mode ( la, modus meaning "manner, tune, measure, due measure, rhythm, melody") may refer to:
Arts and entertainment
* '' MO''D''E (magazine)'', a defunct U.S. women's fashion magazine
* ''Mode'' magazine, a fictional fashion magazine which is ...
rather than a key. Languages other than English may use other
key naming systems.
People sometimes confuse key with
scale. A ''scale'' is an ordered set of notes typically used in a key, while the ''key'' is the "center of gravity" established by particular
chord progressions.
Cadences are particularly important in the establishment of key. Even cadences that do not include the tonic note or triad, such as ''half cadences'' and ''deceptive cadences'', serve to establish key because those chord sequences imply a unique
diatonic context.
Short pieces may stay in a single key throughout. A typical pattern for a simple
song
A song is a musical composition intended to be performed by the human voice. This is often done at distinct and fixed pitches (melodies) using patterns of sound and silence. Songs contain various forms, such as those including the repetiti ...
might be as follows: a
phrase ends with a cadence on the tonic, a second phrase ends with a half cadence, then a final, longer, phrase ends with an authentic cadence on the tonic.
More elaborate pieces may establish the main key, then
modulate to another key, or a series of keys, then back to the original key. In the Baroque it was common to repeat an entire phrase of music, called a
ritornello, in each key once it was established. In Classical
sonata form, the second key was typically marked with a contrasting
theme. Another key may be treated as a temporary tonic, called
tonicization.
In
common practice period compositions, and most of the Western popular music of the 20th century, pieces always begin and end in the same key, even if (as in some
Romantic-era music) the key is deliberately left ambiguous at first. Some
arrangements of popular songs, however, modulate sometime during the song (often in a repeat of the final
chorus
Chorus may refer to:
Music
* Chorus (song) or refrain, line or lines that are repeated in music or in verse
* Chorus effect, the perception of similar sounds from multiple sources as a single, richer sound
* Chorus form, song in which all verse ...
) and thus end in a different key. This is an example of
modulation.
In
rock and
popular music some pieces change back and forth, or modulate, between two keys. Examples of this include
Fleetwood Mac's "
Dreams" and
The Rolling Stones
The Rolling Stones are an English rock band formed in London in 1962. Active for six decades, they are one of the most popular and enduring bands of the rock era. In the early 1960s, the Rolling Stones pioneered the gritty, rhythmically dr ...
' "
Under My Thumb". "This phenomenon occurs when a feature that allows multiple interpretations of key (usually a diatonic set as pitch source) is accompanied by other, more precise evidence in support of each possible interpretation (such as the use of one note as the
root of the initiating harmony and persistent use of another note as pitch of melodic resolution and root of the final harmony of each phrase)."
[Ken Stephenson, ''What to Listen for in Rock: A Stylistic Analysis'' (New Haven: Yale University Press, 2002), 48. .]
Instruments in a key
Certain
musical instruments play in a certain key, or have their music written in a certain key. Instruments that do not play in the key of C are known as
transposing instruments.
[ Kent Wheeler Kennan, ''The Technique of Orchestration'', 2nd edition (Englewood Cliffs, New Jersey: Prentice-Hall, 1970), 1952; .] The most common kind of
clarinet, for example, is said to play in the key of B. This means that a scale written in C major in
sheet music actually sounds as a B major scale when played on the B-flat clarinet—that is, notes sound a
whole tone lower than written. Likewise, the
horn, normally in the key of F, sounds notes a
perfect fifth lower than written.
Similarly, some instruments are "built" in a certain key. For example, a
brass instrument built in B plays a
fundamental note of B, and can play notes in the
harmonic series starting on B without using valves, fingerholes, or slides to alter the length of the vibrating column of air. An instrument built in a certain key often, but not always, uses music written in the same key (see
trombone for an exception). However, some instruments, such as the diatonic
harmonica and the
harp, are in fact designed to play in only one key at a time:
accidentals are difficult or impossible to play.
The highland bagpipes are built in B major, though the music is written in D major with implied accidentals.
In Western musical composition, the key of a piece has important ramifications for its composition:
*As noted earlier, certain instruments are designed for a certain key, as playing in that key can be physically easier or harder. Thus the choice of key can be an important one when composing for an orchestra, as one must take these elements into consideration.
*In the life of the professional clarinetist, for example, it is common to carry two instruments tuned a semitone apart (B and A) to cope with the needs of composers:
Mozart's well-known
clarinet concerto
A clarinet concerto is a concerto for clarinet; that is, a musical composition for solo clarinet together with a large ensemble (such as an orchestra or concert band). Albert Rice has identified a work by Giuseppe Antonio Paganelli as possibly th ...
is in A major. To play it on a B instrument is difficult, and to rewrite all the orchestral parts to B major would be an enormous effort. Even so, it is not unheard of for a piece published in B to include notes a semitone (or more) below the range of the common B clarinet. The piece must then be played on a more exotic instrument, or transposed by hand (or at sight) for the slightly larger A clarinet. There are clarinets with an extended range, with a longer bore and additional keys.
*Besides this though, the
timbre of almost any instrument is not exactly the same for all notes played on that instrument. For this reason a piece that might be in the key of C might sound or "feel" somewhat different (besides being in a different pitch) to an observer if it is transposed to the key of A.
*In addition, since many composers often utilized the piano while composing, the key chosen can possibly have an effect over the composing. This is because the physical fingering is different for each key, which may lend itself to choosing to play and thus eventually write certain notes or chord progressions compared to others, or this may be done on purpose to make the fingering more efficient if the final piece is intended for piano.
*In music that does not use
equal temperament, chords played in different keys are qualitatively different.
Key coloration
Key coloration is the difference between the
intervals of different keys in a single non-equal tempered tuning, and the overall sound and "feel" of the key created by the tuning of its intervals.
Historical irregular
musical temperaments usually have the narrowest
fifths between the
diatonic notes ("naturals") producing purer
third
Third or 3rd may refer to:
Numbers
* 3rd, the ordinal form of the cardinal number 3
* , a fraction of one third
* 1⁄60 of a ''second'', or 1⁄3600 of a ''minute''
Places
* 3rd Street (disambiguation)
* Third Avenue (disambiguation)
* Hi ...
s, and wider fifths among the chromatic notes ("sharps and flats"). Each key then has a slightly different
intonation, hence different keys have distinct characters. Such "key coloration" was an essential part of much eighteenth- and nineteenth-century music and was described in treatises of the period.
For example, in tunings with a
wolf fifth, the key on the lowest note of the fifth sounds dramatically different from other keys (and is often avoided). In
Pythagorean tuning on C (C, E+, G: 4, 5, 6), the major triad on C is just while the major triad on E+++ (F) is noticeably out of tune (E+++, A+, C: , 5, 6) due to E+++ (521.44 cents) being a
Pythagorean comma (23.46 cents) larger sharp compared to F.
Music using
equal temperament lacks key coloration because all keys have the same pattern of intonation, differing only in pitch.
References
Further reading
*Innig, Renate (1970). ''System der Funktionsbezeichnung in den Harmonielehren seit
Hugo Riemann''. Düsseldorf: Gesellschaft zur Förderung der systematischen Musikwissenschaft.
*
Rahn, John (1980). ''Basic Atonal Theory''. New York: Longman; London and Toronto: Prentice Hall International. . Reprinted 1987, New York: Schirmer Books; London: Collier Macmillan.
*
Steblin, Rita (1983). ''A History of Key Characteristics in the 18th and Early 19th Centuries''. UMI Research Press, Ann Arbor.
External links
Christian Schubart's "Affective Key Characteristic"– from various sources.
{{DEFAULTSORT:Key (Music)
Musical tuning
Tonality