Key (music)

Scale degree names^[1] (C major scale).

In music theory, the term key is used in many different and sometimes contradictory ways. A common use is to speak of music as being "in" a specific key, such as in the key of C major or in the key of F-sharp. Sometimes the terms "major" or "minor" are appended, as in the key of A minor or in the key of B-flat major. Although the concept of musical key can be a complicated subject when examined closely, broadly speaking the phrase in key of C means that C is music's harmonic center or tonic. Note that the letter-name "C" does not indicate a single specific pitch but rather all pitches with the letter name C (sometimes called a pitch class). The terms "major" and "minor" further imply the use of a major scale or a minor scale. Thus the phrase in the key of E major implies a piece of tonal music harmonically centered on the note E and making use of a major scale whose first note, or tonic, is E. Although the term "key" is commonly used this way, actual music can rarely be described so simply. This overview of the term also makes many assumptions and may not hold true for all forms of music.

A key relationship is the relationship between keys, measured by common tones and nearness on the circle of fifths. See: closely related key.

Keys and tonality

The key identifies the tonic triad, the chord, major or minor, which represents the final point of rest for a piece, or the focal point of a section. Although the key of a piece may be named in the title (e.g., Symphony in C), 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. A key may be major or minor; music can be described as being in the Dorian mode, or Phrygian, et cetera, and is thus usually considered to be in a specific mode rather than a key. When a particular key is not being described in the English language, different key naming systems may be used.

Although many musicians 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.^[2]

The chords used within a key are generally drawn from the major or minor scale associated with the tonic triad, but may also include borrowed chords, altered chords, secondary dominants, and the like. All of these chords, however, are used in conventional patterns which serve to establish the primacy of the tonic triad.

Cadences are particularly important in the establishment of key. Even cadences which do not include the tonic 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 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, will shift up a half-step or a whole step sometime during the song (often in a repeat of the final chorus) and thus will end in a different key. This is an example of modulation.

In rock and popular music some pieces, "tend to float back and forth between two keys," with examples including Fleetwood Mac's "Dreams" and The Rolling Stones' "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)."^[3] Most commonly between relative major and minor, which share, "exactly the same pitch classes," such as C Ionian and A Aeolian.^[3]

Examples of, "songs employing a fourth relationship include," the Buckinghams's "Kind Of A Drag", the Corrs' "Breathless", and Paul Simon's "Kodachrome".^[3]

"Songs whose main sections [often verse and chorus] juxtapose keys of a chromatic third relationship include,"

• minor third: the Doobie Brothers' "What A Fool Believes", Chicago's "(I've Been) Searchin' So Long", The Beatles' "Something", and Diana Ross' "Upside Down".^[3]
• major third: Steve Winwood's "While You See A Chance", Sanford Townsend Band's "Smoke Of A Distant Fire", The Guess Who's "Hand Me Down World", and Duran Duran's "Hungry Like The Wolf".^[3]

"Songs whose major sections juxtapose keys sharing a chromatic second relationship include,"

• minor second: The Beach Boys' "Don't Worry, Baby".^[3]
• major second: Bread's "It Don't Matter To Me", Bee Gees' "I've Got to Get a Message To You", and Huey Lewis and the News' "Stuck With You".^[3]

Instruments in a key

Certain musical instruments are sometimes said to play in a certain key, or have their music written in a certain key. Instruments which do not play in the key of C are known as transposing instruments.^[4] The most common kind of clarinet, for example, is said to play in the key of B-flat. This means that a scale written in C major in sheet music will actually sound as a B-flat 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 may be said to be built in a certain key. For example, a brass instrument built in B-flat will play a fundamental note of B-flat, and will be able to play notes in the harmonic series starting on B-flat without using valves, fingerholes, or slides or otherwise altering the length of the vibrating column of air. An instrument built in a certain key will often, but not always, have its 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.

In Western musical composition, the key of a song has important ramifications for its composition:

• As noted earlier, certain instruments are said to be 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 clarinettist, for example, it is common to carry two instruments tuned a semitone apart (B-flat and A) to cope with the needs of composers: Mozart's well-known clarinet concerto is in A Major. To play it on a B-flat instrument would be difficult, and to rewrite all the orchestral parts to allow the piece to be played in B-flat major would be an enormous effort. Even so, it is not unheard of for a piece published in B-flat to include notes a semitone (or more) below the range of the common B-flat 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 song 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" 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 thirds, 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 will have a dramatically different sound than the 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: 4.125, 5, 6) due to E♯+++ (521.44 cents) being a Pythagorean comma(23.46 cents) larger sharp compared to F♮.

Modern music lacks key coloration because it uses equal temperament in which all keys have the same pattern of intonation, differing only in pitch.

Sources

1. ^ Bruce Benward and Marilyn Nadine Saker, Music: In Theory and Practice, Vol. I, seventh edition (Boston: McGraw-Hill, 2003), 33. ISBN 978-0-07-294262-0.
2. ^ Willi Apel, Harvard Dictionary of Music (Cambridge: Harvard University Press, 1969), 450.
3. ^ ^{a b c d e f g} Ken Stephenson, What to Listen for in Rock: A Stylistic Analysis (New Haven: Yale University Press, 2002), 48. ISBN 9780300092394.
4. ^ Kent Wheeler Kennan, The Technique of Orchestration, second edition (Englewood Cliffs, New Jersey: Prentice-Hall, Inc., 1970), 1952; ISBN 0-13-900316-9.

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. ISBN 0-02-873160-3. 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

• A simple, but accurate, explanation of the function of "keys" in music
• Christian Schubart's "Affective Key Characteristic"
• Characteristics of Musical Keys - from various sources.

Key coloration

• http://www.rollingball.com/A01c.htm
• http://campus.murraystate.edu/staff/scott.thile/research/unequal/index.htm