Editing Time signature (section)

==Mixed meters==
While time signatures usually express a regular pattern of beat stresses continuing through a piece (or at least a section), sometimes composers change time signatures often enough to result in music with an extremely irregular rhythm. The time signature may switch so much that a piece may not be best described as being in one meter, but rather as having a switching mixed meter. In this case, the time signatures are an aid to the performers and not ''necessarily'' an indication of meter. The Promenade from [[Modest Mussorgsky]]'s ''[[Pictures at an Exhibition]]'' (1874) is a good example. The opening measures are shown below:

:<score sound="1">
    { \new PianoStaff <<
        \new Staff <<
            \new voice \relative c'' {
                \set Score.tempoHideNote = ##t \tempo 4 = 112
                \clef treble \key bes \major 
				\time 5/4 
                	g4--_\f^\markup { \bold {Allegro giusto, nel modo russico; senza allegrezza, ma poco sostenuto. } } f-- bes-- c8--( f d4--)
                \time 6/4
					c8--( f d4--) bes-- c-- g-- f--
				\time 5/4
					<bes, d g>4 <a c f> <bes d bes'> \stemDown <c a'> \stemNeutral <f a d>
				\time 6/4
					\stemDown <c a'> \stemNeutral <f bes d> <d g bes> <e g c> <g, c g'> <a c f>
				}
			\new Voice \relative c'' {
                \time 5/4
					s1 s4
				\time 6/4
					s1.
				\time 5/4
					s2. \stemUp c8^( f d4)
				\time 6/4
					\stemUp c8^( f d4) s1
                }
            >>
        \new Staff <<
			\clef bass \key bes \major 
            \relative c {
                \time 5/4
					R1*5/4
				\time 6/4
					R1*6/4
				\time 5/4
					<g g'>4 <a f'> <g g'> <f f'> <d d'>
                \time 6/4
					<f f'> <bes bes'> <g g'> <c, c'> <e e'> <f f'>
				}
            >>
    >> }
</score>

:

[[Igor Stravinsky]]'s ''[[The Rite of Spring]]'' (1913) is famous for its "savage" rhythms. Five measures from "Sacrificial Dance" are shown below:

:<score sound="1"> { \new PianoStaff << \new Staff \relative c'' { \set Staff.midiInstrument = #"violin" \clef treble \tempo 8 = 126 \override DynamicLineSpanner.staff-padding = #4 \time 3/16 r16 <d c a fis d>-! r16\fermata | \time 2/16 r <d c a fis d>-! \time 3/16 r <d c a fis d>8-! | r16 <d c a fis d>8-! | \time 2/8 <d c a fis>16-! <e c bes g>->-![ <cis b aes f>-! <c a fis ees>-!] } \new Staff \relative c { \set Staff.midiInstrument = #"violin" \clef bass \time 3/16 d,16-! <bes'' ees,>^\f-! r\fermata | \time 2/16 <d,, d,>-! <bes'' ees,>-! | \time 3/16 d16-! <ees cis>8-! | r16 <ees cis>8-! | \time 2/8 d16^\sf-! <ees cis>-!->[ <d c>-! <d c>-!] } >> } </score>

In such cases, a convention that some composers follow (e.g., [[Olivier Messiaen]], in his ''[[La Nativité du Seigneur]]'' and ''[[Quatuor pour la fin du temps]]'') is to simply omit the time signature. [[Charles Ives]]'s ''[[Concord Sonata]]'' has measure bars for select passages, but the majority of the work is unbarred.

Some pieces have no time signature, as there is no discernible meter. This is sometimes known as [[free time (music)|free time]]. Sometimes one is provided (usually {{music|time|4|4}}) so that the performer finds the piece easier to read, and simply has "free time" written as a direction. Sometimes the word ''FREE'' is written downwards on the staff to indicate the piece is in free time. [[Erik Satie]] wrote many compositions that are ostensibly in free time but actually follow an unstated and unchanging simple time signature. Later composers used this device more effectively, writing music almost devoid of a discernibly regular pulse.

If two time signatures alternate repeatedly, sometimes the two signatures are placed together at the beginning of the piece or section, as shown below:

:[[File:Tchaikovsky String Quartet in F excerpt.png|center|thumb|460px|Detail of a score of Tchaikovsky's [[String Quartet No. 2 (Tchaikovsky)|String Quartet No.&nbsp;2 in F major]], showing a multiple time signature]]