- Time signatures (meters) are made up of two numbers on the musical stave, one above the other.
- The lower number is the chosen unit of measurement (eg. minim, quarter note).
- The upper number is the number of units per bar.
- The number of beats in a bar depends on the time signature and the speed (tempo) of the music
Guide to Time Signatures
As you can see from the Guide above, the most commonly-used units of measurement (ie. the lower numbers) are 2 (Half Note or Minim), 4 (Quarter Note or Crotchet) and 8 (Sixteenth Note or Quaver).
The upper numbers indicate the number of units within each bar / measure. For example, a time signature of 3/4 means there are three quarter notes (crotchets) in each bar.
Video tutorial on Time Signatures from the online course You Got Rhythm!
Number of beats per measure depends on speed (tempo)
The upper number does not necessarily indicate the number of beats in a bar. The simplest example is the time signature of 6/8. There are six eighth notes (quavers) in each bar. At a moderate tempo, however, there are only two beats per bar, each beat a dotted quarter note (dotted crotchet). It is only in slow tempos that counting in six makes sense. In that instance, counting in 6 beats in a bar would be easier to feel and play.
Another example is the time signature of 3/4, which, at a very fast tempo, is easier to think of in one beat per bar, each beat a dotted half note (dotted minim).
Time signatures: what they do
- Time signatures (‘meters’) help communicate ‘feel’.
- They organize music into even sections called ‘bars’ or ‘measures’.
- Each measure is separated by a bar line
- Bar lines make music easier to read.
Time signatures can change
You can find time signatures at the beginning of sheet music after the clef and key signature.
The time signature can change. You can change the time signature whenever you like. Orchestral works such as Stravinsky’s Rite of Spring can frequently change time signatures.
Commonly-used time signatures
The most usual time signatures are:
- 4/4 also known as Common Time
- 3/4
- 2/4
- 5/4
- 2/2 also known as Cut Common
And the so-called “Compound” meters:
- 3/8
- 6/8
- 9/8
- 12/8
Compound meters refers to time signatures where the length of the beat is a dotted note.
Time signature and tempo affects the feel
2/4 has the feel of a march at a normal tempo.
3/4 has the feel of a waltz at a normal tempo with three beats per bar. At a very fast tempo, where there would be only one beat per bar, the feel is not a waltz unless you’re a fast waltzer!
Rare and unusual time signatures
Any time signature with a ‘4’ as the lower number, ie. with a quarter note / crotchet as the unit of measurement, is not so unusual. Even 5/4 is pretty common and so makes it onto the Guide to Commonly Used Time Signatures.
Theoretically, the upper number of time signatures can be anything. 17/16 is 17 sixteenth notes (17 semiquavers) in a bar. This has been used by metal band Meshuggah in the first few measures of ‘Do Not Look Down’.
The lower number can be as low as ‘1’ (ie. a whole note (semibreve) is the unit of measure). This is extremely rare.
Following ‘1’, the only possibilities are 2, 4, 8 and 16. You probably will never see a 32 as the lower number, as the unit of measure is a 32nd Note (Demisemiquaver)! That would make the rhythm extremely difficult to read.
Take a look at the following examples of “Happy Birthday to You”.
As time signatures are supposed to make music easier to read, most composers and song writers steer clear of wacky time signatures. You can’t actually hear the difference between 3/8 and 3/1 if the beats are played at the same tempos.
Conclusion
Whether you are learning the piano, guitar or ukulele, whether you play jazz, classical or metal, being able to read and interpret time signatures is an essential skill in learning to read music.
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