Editing Metre (music) (section)

===Metres classified by the subdivisions of a beat===
{{anchor|Meters classified by the subdivisions of a beat}}
Simple metre and compound metre are distinguished by the way the beats are subdivided.

====Simple metre====<!--[[Simple meter]] redirects here-->
{{anchor|Simple meter}}
Simple metre (or simple time) is a metre in which each beat of the bar divides naturally into two (as opposed to three) equal parts. The top number in the time signature will be 2, 3, 4, 5, etc.

For example, in the time signature {{music|time|3|4}}, each bar contains three quarter-note beats, and each of those beats divides into two [[eighth note]]s, making it a simple metre. More specifically, it is a simple ''triple'' metre because there are three beats in each measure; simple duple (two beats) or simple quadruple (four) are also common metres.

:{|
|<score sound="1" override_midi="Simple duple drum pattern.mid">
    \new Staff <<
       \new voice \relative c' {
           \clef percussion
           \numericTimeSignature
           \time 2/4
           \set Score.tempoHideNote = ##t \tempo 4 = 100
           \stemDown \repeat volta 2 { g4 d' }
       }
       \new voice \relative c'' {
           \override NoteHead.style = #'cross
           \stemUp \repeat volta 2 { a8 a a a }
       }
   >>
</score>
|<score sound="1" override_midi="Simple triple drum pattern.mid">
    \new Staff <<
       \new voice \relative c' {
           \clef percussion
           \numericTimeSignature
           \time 3/4
           \set Score.tempoHideNote = ##t \tempo 4 = 100
           \stemDown \repeat volta 2 { g4 d' d }
       }
       \new voice \relative c'' {
           \override NoteHead.style = #'cross
           \stemUp \repeat volta 2 { a8[ a] a[ a] a[ a] }
       }
   >>
</score>
|<score sound="1" override_midi="Characteristic rock drum pattern.mid">
    \new Staff <<
       \new voice \relative c' {
           \clef percussion
           \numericTimeSignature
           \time 4/4
           \set Score.tempoHideNote = ##t \tempo 4 = 100
           \stemDown \repeat volta 2 { g4 d' g, d' }
       }
       \new voice \relative c'' {
           \override NoteHead.style = #'cross
           \stemUp \repeat volta 2 { a8 a a a a a a a }
       }
   >>
</score>
|}

====Compound metre==== <!-- Compound_meter page links directly to here -->
{{anchor|Compound meter}}
Compound metre (or compound time), is a metre in which each beat of the bar divides naturally into three equal parts. That is, each [[beat (music)|beat]] contains a triple pulse.{{sfn|Latham|2002a}} The top number in the time signature will be 6, 9, 12, 15, 18, 24, etc.

Compound metres are written with a time signature that shows the number of ''divisions'' of beats in each bar as opposed to the number of beats. For example, compound duple (two beats, each divided into three) is written as a time signature with a numerator of six, for example, {{music|time|6|8}}. Contrast this with the time signature {{music|time|3|4}}, which also assigns six eighth notes to each measure, but by convention connotes a simple triple time: 3 quarter-note beats.

Examples of compound metre include {{music|time|6|8}} (compound duple metre), {{music|time|9|8}} (compound triple metre), and {{music|time|12|8}} (compound quadruple metre).

:{|
|<score sound="1" override_midi="Compound duple drum pattern.mid">
   \new Staff <<
       \new voice \relative c' {
           \clef percussion
           \numericTimeSignature
           \time 6/8
           \set Score.tempoHideNote = ##t \tempo 4. = 80
           \stemDown \repeat volta 2 { g4. d' }
       }
       \new voice \relative c'' {
           \override NoteHead.style = #'cross
           \stemUp \repeat volta 2 { a8 a a a a a }
       }
   >>
</score>
|<score sound="1" override_midi="Compound triple drum pattern.mid">
    \new Staff <<
       \new voice \relative c' {
           \clef percussion
           \numericTimeSignature
           \time 9/8
           \set Score.tempoHideNote = ##t \tempo 4. = 80
           \stemDown \repeat volta 2 { g4. d' d }
       }
       \new voice \relative c'' {
           \override NoteHead.style = #'cross
           \stemUp \repeat volta 2 { a8 a a a a a a a a }
       }
   >>
</score>
|<score sound="1" override_midi="Compound quadruple drum pattern.mid">
    \new Staff <<
       \new voice \relative c' {
           \clef percussion
           \numericTimeSignature
           \time 12/8
           \set Score.tempoHideNote = ##t \tempo 4. = 80
           \stemDown \repeat volta 2 { g4. d' g, d' }
       }
       \new voice \relative c'' {
           \override NoteHead.style = #'cross
           \stemUp \repeat volta 2 { a8 a a a a a a a a a a a }
       }
   >>
</score>
|}

Although {{music|time|3|4}} and {{music|time|6|8}} are not to be confused, they use bars of the same length, so it is easy to "slip" between them just by shifting the location of the accents. This interpretational switch has been exploited, for example, by [[Leonard Bernstein]], in the song "[[America (Leonard Bernstein song)|America]]":
[[File:Alternating time signatures2.gif|center|thumb|340x340px|"[[America (West Side Story song)|I like to be in A-mer-i-ca]]" from ''[[West Side Story]]''[[File:Alternating time signatures2.mid]]]]

Compound metre divided into three parts could theoretically be transcribed into musically equivalent simple metre using [[tuplet|triplets]]. Likewise, simple metre can be shown in compound through duples. In practice, however, this is rarely done because it disrupts [[Beat pattern|conducting patterns]] when the [[tempo]] changes. When conducting in {{music|time|6|8}}, conductors typically provide two beats per bar; however, all six beats may be performed when the tempo is very slow.

Compound time is associated with "lilting" and dancelike qualities. Folk dances often use compound time. Many [[Baroque dance]]s are often in compound time: some [[gigue]]s, the [[courante]], and sometimes the [[passepied]] and the [[siciliana]].