Notation & reading
Time signature
A time signature is a pair of numbers showing how many of a given note value fill a bar; their grouping indicates the metre and main beats.
The upper number counts the note values named by the lower number, 4 means quarter notes (crotchets), 8 means eighth notes (quavers). In simple metre, 3/4 has three quarter-note beats per bar. In compound metre, 6/8 has six eighth notes normally grouped into two dotted-quarter beats, each divided in three. The same total of six eighth notes can therefore be grouped as 2 + 2 + 2 in 3/4 or 3 + 3 in 6/8.
Common time, the C symbol, means 4/4; the same symbol with a vertical stroke means cut time, or 2/2, where the half note takes the beat. Reading the metre correctly before playing a note is what makes a rhythm feel right rather than merely be correct.
Try it now · no account needed
Compare 3/4 and 6/8 by clapping
Both bars can contain six eighth notes (quavers), but their normal grouping differs. Clap every syllable below and stress the capitalized numbers.
3/4: ONE and TWO and THREE and 6/8: ONE la li TWO la li
In 3/4, three quarter-note beats each divide into two eighth notes: 2 + 2 + 2. In 6/8, two dotted-quarter beats each divide into three eighth notes: 3 + 3. If you keep the eighth notes equally spaced, the bar lengths match but the accents move.
Check your understanding
In a normal 6/8 bar, how many main beats are there, and which note value represents each main beat?
Show answer and explanation
Two main beats, each a dotted quarter note (dotted crotchet). Each contains three eighth notes, so the two beats account for all six eighth notes in the bar.
A common mix-up
The upper number does not always count the main beats. In compound metres such as 6/8, 9/8 and 12/8, it counts the subdivisions: normally two, three or four main beats respectively. Very slow music may be counted in smaller units.
Related terms
Every term in this glossary is taught in context somewhere in Arco's curricula, on the staff, on the keyboard, and on your own fingerboard at the same time.