![Unison on C](https://upload.wikimedia.org/wikipedia/commons/d/db/Unison_on_C.png)
In
music
Music is generally defined as the art of arranging sound to create some combination of form, harmony, melody, rhythm or otherwise expressive content. Exact definitions of music vary considerably around the world, though it is an aspect ...
, unison is two or more
musical parts that sound either the same
pitch or pitches separated by
intervals of one or more
octave
In music, an octave ( la, octavus: eighth) or perfect octave (sometimes called the diapason) is the interval between one musical pitch and another with double its frequency. The octave relationship is a natural phenomenon that has been refer ...
s, usually at the same time. ''Rhythmic unison'' is another term for
homorhythm
In music, homorhythm (also homometer) is a texture having a "similarity of rhythm in all parts"Griffiths, Paul (2005). ''The Penguin Companion to Classical Music'', p.375. . or "very similar rhythm" as would be used in simple hymn
A hymn is ...
.
Definition
Unison or perfect unison (also called a prime, or perfect prime)
[Benward & Saker (2003), p. 53.] may refer to the (pseudo-)
interval formed by a tone and its duplication (in German, ''Unisono'', ''Einklang'', or ''Prime''), for example C–C, as differentiated from the
second
The second (symbol: s) is the unit of time in the International System of Units (SI), historically defined as of a day – this factor derived from the division of the day first into 24 hours, then to 60 minutes and finally to 60 seconds ...
, C–D, etc. In the unison the two pitches have the ratio of 1:1 or 0
half step
A semitone, also called a half step or a half tone, is the smallest musical interval commonly used in Western tonal music, and it is considered the most dissonant when sounded harmonically.
It is defined as the interval between two adjacent no ...
s and zero
cents. Although two tones in unison are considered to be the same pitch, they are still perceivable as coming from separate sources, whether played on instruments of a different type: ; or of the same type: . This is because a pair of tones in unison come from different locations or can have different "colors" (
timbre
In music, timbre ( ), also known as tone color or tone quality (from psychoacoustics), is the perceived sound quality of a musical note, sound or musical tone, tone. Timbre distinguishes different types of sound production, such as choir voice ...
s), i.e. come from different
musical instrument
A musical instrument is a device created or adapted to make musical sounds. In principle, any object that produces sound can be considered a musical instrument—it is through purpose that the object becomes a musical instrument. A person who pl ...
s or human voices. Voices with different colors have, as sound waves, different
waveform
In electronics, acoustics, and related fields, the waveform of a signal is the shape of its graph as a function of time, independent of its time and magnitude scales and of any displacement in time.David Crecraft, David Gorham, ''Electronic ...
s. These waveforms have the same fundamental
frequency
Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is eq ...
but differ in the amplitudes of their higher
harmonic
A harmonic is a wave with a frequency that is a positive integer multiple of the ''fundamental frequency'', the frequency of the original periodic signal, such as a sinusoidal wave. The original signal is also called the ''1st harmonic'', the ...
s. The unison is considered the most
consonant
In articulatory phonetics, a consonant is a speech sound that is articulated with complete or partial closure of the vocal tract. Examples are and pronounced with the lips; and pronounced with the front of the tongue; and pronounced wit ...
interval while the
near unison is considered the most
dissonant
In music, consonance and dissonance are categorizations of simultaneous or successive Sound, sounds. Within the Western tradition, some listeners associate consonance with sweetness, pleasantness, and acceptability, and dissonance with harshness ...
. The unison is also the easiest interval to
tune. The unison is abbreviated as "P1".
However, the unison was questioned by
Zarlino
Gioseffo Zarlino (31 January or 22 March 1517 – 4 February 1590) was an Italian music theorist and composer of the Renaissance. He made a large contribution to the theory of counterpoint as well as to musical tuning.
Life and career
Zarlino w ...
as an interval for lacking contrast and compared to a
point
Point or points may refer to:
Places
* Point, Lewis, a peninsula in the Outer Hebrides, Scotland
* Point, Texas, a city in Rains County, Texas, United States
* Point, the NE tip and a ferry terminal of Lismore, Inner Hebrides, Scotland
* Point ...
in geometry:
Performance ensembles
![Twinkle Twinkle in octaves](https://upload.wikimedia.org/wikipedia/commons/a/aa/Twinkle_Twinkle_in_octaves.png)
In orchestral music ''unison'' can mean the simultaneous playing of a note (or a series of notes constituting a
melody
A melody (from Greek language, Greek μελῳδία, ''melōidía'', "singing, chanting"), also tune, voice or line, is a Linearity#Music, linear succession of musical tones that the listener perceives as a single entity. In its most liter ...
) by different instruments, either at the same
pitch; or in a different
octave
In music, an octave ( la, octavus: eighth) or perfect octave (sometimes called the diapason) is the interval between one musical pitch and another with double its frequency. The octave relationship is a natural phenomenon that has been refer ...
, for example,
cello
The cello ( ; plural ''celli'' or ''cellos'') or violoncello ( ; ) is a Bow (music), bowed (sometimes pizzicato, plucked and occasionally col legno, hit) string instrument of the violin family. Its four strings are usually intonation (music), t ...
and
double bass
The double bass (), also known simply as the bass () (or #Terminology, by other names), is the largest and lowest-pitched Bow (music), bowed (or plucked) string instrument in the modern orchestra, symphony orchestra (excluding unorthodox addit ...
(''all'unisono''). Typically a section string player plays unison with the rest of the section. Occasionally the Italian word ''
divisi In musical terminology, ''divisi'', or as typically printed ''“div.,”'' is an instruction to divide a single section of instruments into multiple subsections. This usually applies to the violins of the string section in an orchestra, although v ...
'' (meaning ''divided'', abbrev. ''div.'') marks a point where an instrumental section, typically the first violins, is to be divided into two groups for rendering passages that might, for example, include full
chords
Chord may refer to:
* Chord (music), an aggregate of musical pitches sounded simultaneously
** Guitar chord a chord played on a guitar, which has a particular tuning
* Chord (geometry), a line segment joining two points on a curve
* Chord ( ...
. Thus, in the ''divisi'' first violins the "outside" players (nearer the audience) might play the top note of the chord, while the "inside" seated players play the middle note, and the second violins play the bottom note. At the point where the first violins no longer play ''divisi'', the score may indicate this with ''unison'' (abbrev. ''unis.'').
When an entire
choir
A choir ( ; also known as a chorale or chorus) is a musical ensemble of singers. Choral music, in turn, is the music written specifically for such an ensemble to perform. Choirs may perform music from the classical music repertoire, which ...
sings the main melody, the choir usually sings in unison. Music in which all the notes sung are in unison is called
monophonic
Monaural or monophonic sound reproduction (often shortened to mono) is sound intended to be heard as if it were emanating from one position. This contrasts with stereophonic sound or ''stereo'', which uses two separate audio channels to reproduc ...
. In a choir with two or more sections, such as for different
vocal range
Vocal range is the range of pitches that a human voice can phonate. A common application is within the context of singing, where it is used as a defining characteristic for classifying singing voices into voice types. It is also a topic of stud ...
s, each section typically sings in unison. Part singing is when two or more voices sing different notes.
Homophony
In music, homophony (;, Greek: ὁμόφωνος, ''homóphōnos'', from ὁμός, ''homós'', "same" and φωνή, ''phōnē'', "sound, tone") is a texture in which a primary part is supported by one or more additional strands that flesh ou ...
is when choir members sing different pitches but with the same rhythm.
Polyphony
Polyphony ( ) is a type of musical texture consisting of two or more simultaneous lines of independent melody, as opposed to a musical texture with just one voice, monophony, or a texture with one dominant melodic voice accompanied by chords, h ...
is when the chorus sings multiple independent melodies.
Synthesizer
On
synthesizer
A synthesizer (also spelled synthesiser) is an electronic musical instrument that generates audio signals. Synthesizers typically create sounds by generating waveforms through methods including subtractive synthesis, additive synthesis and ...
s, the term ''unison'' is used to describe two or more
oscillator
Oscillation is the repetitive or periodic variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states. Familiar examples of oscillation include a swinging pendulum ...
s that are slightly detuned in correspondence to each other, which makes the sound fatter. This technique is so popular that some modern
virtual analog
An analog modeling synthesizer is a synthesizer that generates the sounds of traditional analog synthesizers using DSP components and software algorithms. Analog modeling synthesizers simulate the behavior of the original electronic circuitry in o ...
synthesisers have a special oscillator type called "
super saw" or "hyper saw" that generates several detuned sawtooth waves simultaneously.
See also
*
List of musical intervals
*
List of pitch intervals
Below is a list of intervals expressible in terms of a prime limit (see Terminology), completed by a choice of intervals in various equal subdivisions of the octave or of other intervals.
For commonly encountered harmonic or melodic intervals ...
References
Further reading
*
Apel, Willi, ed., ''Harvard Dictionary of Music'', Second Edition, Revised and Enlarged. The Belknap Press of Harvard University Press, Cambridge, Massachusetts, 1969. .
{{Intervals
Unisons
Just tuning and intervals
Perfect intervals
3-limit tuning and intervals