Duple and quadruple metre

Duple metre (or Am. duple meter, also known as duple time) is a musical metre characterized by a primary division of 2 beats to the bar, usually indicated by 2 and multiples (simple) or 6 and multiples (compound) in the upper figure of the time signature, with ²
₂ (cut time), ²
₄, and ⁶
₈ (at a fast tempo) being the most common examples.

Shown below are a simple and a compound duple drum pattern.

<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="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>

Though the upper number must be divisible by 2, the mere fact that 2 evenly divides the upper figure does not in and of itself indicate a duple metre; it is only a prerequisite.

The most common time signature in rock, blues, country, funk, and pop is ⁴
₄. Although jazz writing has become more adventurous since Dave Brubeck's Time Out, the majority of jazz and jazz standards are still in "common time" (⁴
₄).

Duple time is common in many styles including the polka, well known for its obvious "oom-pah" duple feel. Compare to the waltz.

Quadruple metre

Quadruple metre (also quadruple time) is a musical metre characterized in modern practice by a primary division of 4 beats to the bar, usually indicated by 4 in the upper figure of the time signature, with ⁴
₄ (common time, also notated as ) being the most common example.

Shown below are a simple and a compound quadruple drum pattern.

<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>

<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>