8.4.1 Polymetric notation

Double time signatures are not supported explicitly, but they can be faked. In the next example, the markup for the time signature is created with a markup text. This markup text is inserted in the TimeSignature grob. See also input/test/compound-time.ly).

% create 2/4 + 5/8
tsMarkup =\markup {
  \override #'(baseline-skip . 2) \number {
    \column { "2" "4" }
    \vcenter "+"
    \bracket \column { "5" "8" }
  }
}

{
  \override Staff.TimeSignature #'stencil = #ly:text-interface::print
  \override Staff.TimeSignature #'text = #tsMarkup
  \time 3/2
  c'2 \bar ":" c'4 c'4.
}

Each staff can also have its own time signature. This is done by moving the Timing_translator to the Staff context.

\layout {
  \context { \Score
     \remove "Timing_translator"
     \remove "Default_bar_line_engraver"
  }
  \context {
    \Staff
    \consists "Timing_translator"
    \consists "Default_bar_line_engraver"
  }

}

Now, each staff has its own time signature.

<<
  \new Staff {
    \time 3/4
    c4 c c | c c c |
  }
  \new Staff {
    \time 2/4
    c4 c | c c | c c
  }
  \new Staff {
    \time 3/8
    c4. c8 c c c4. c8 c c
  }
>>

A different form of polymetric notation is where note lengths have different values across staves.

This notation can be created by setting a common time signature for each staff but replacing it manually using timeSignatureFraction to the desired fraction. Then the printed durations in each staff are scaled to the common time signature. The latter is done with \compressMusic, which is used similar to \times, but does not create a tuplet bracket. The syntax is

\compressMusic #'(numerator . denominator) musicexpr

In this example, music with the time signatures of 3/4, 9/8, and 10/8 are used in parallel. In the second staff, shown durations are multiplied by 2/3, so that 2/3 * 9/8 = 3/4, and in the third staff, shown durations are multiplied by 3/5, so that 3/5 * 10/8 = 3/4.

     
     \relative c' { <<
       \new Staff {
         \time 3/4
         c4 c c | c c c |
       }
       \new Staff {
         \time 3/4
         \set Staff.timeSignatureFraction = #'(9 . 8)
         \compressMusic #'(2 . 3)
           \repeat unfold 6 { c8[ c c] }
       }
       \new Staff {
         \time 3/4
         \set Staff.timeSignatureFraction = #'(10 . 8)
         \compressMusic #'(3 . 5) {
           \repeat unfold 2 { c8[ c c] }
           \repeat unfold 2 { c8[ c] }
           | c4. c4. \times 2/3 { c8 c c } c4
         }
       }
     >> }

Bugs

When using different time signatures in parallel, the spacing is aligned vertically, but bar lines distort the regular spacing.