Digital Sound & Music: Concepts, Applications, & Science, Chapter 3, last updated 6/25/2013
size ½, a quarter note is size ¼, and so forth.) A time signature of time is shown in Figure
3.16, indicating four beats to a measure with a quarter note getting one beat. A time signature of
indicates three beats to a measure with a quarter note getting one beat. This is the meter for a
Figure 3.16 Time signature showing time
If the time signature of a piece is , then there are four beats to a measure and each quarter
note gets a beat. Consider the score in Figure 3.17, which shows you how to play “Twinkle,
Twinkle Little Star” in time in the key of C. Each of the six syllables in “Twin-kle Twin-kle
Lit-tle” corresponds to a quarter note, and each is given equal time – one beat – in the first
measure. Then the note corresponding to the word “star” is held for two beats in the second
measure. Measures three and four are similar to measures one and two.
Figure 3.17 Score for right hand of “Twinkle, Twinkle Little Star”
Directions for tempo and rhythm are part of musical notation. As we’ve already seen, a
musical score begins with an indication of how rhythm is to be handled in the form of a time
signature that tells how many beats there are to a measure and which type of note gets one beat.
The most common time signatures are , , and , but other timings are possible. time is so
common that it is sometimes abbreviated on the time signature as C for “common time.”
Exactly how long it takes to play a measure depends on the tempo of the overall piece.
The tempo of a musical piece depends on which type of note is given one beat and how
many beats there are per second. Tempo can be expressed at the beginning of the score
explicitly, in terms of beats per minute (BPM). For example, a marking such as = 72 placed
above a measure indicates that a tempo of 72 beats per minute is recommend from this point on,
with a quarter note getting one beat. Alternatively, an Italian key word like allegro or andante
can be used to indicate the beats per minute in a way that can be interpreted more subjectively.
A list of some of these tempo markings is given in Table 3.4.