The_Complete_Idiot%27s_Guide_To_Music_Theory

Time Signatures
In This Chapter
◆ Understanding how time signatures determine meter
◆ Learning both usual and odd time signatures
◆ Changing time signatures
◆ Subdividing odd time signatures
6
Chapter
In the previous chapter you learned about measures, those containers that hold
the beats of a piece of music. The start and end points of a measure are marked
by vertical bar lines, and multiple measures combine to create a complete song.
To simplify things, in Chapter 5 we limited our discussion to measures with
four beats apiece, with each of those beats equaling a quarter note. That covers
a lot of different songs, especially in popular music. Whatever type of music
you listen to—rock-and-roll, soul, jazz, country, hip hop, or even reggae—most
of the songs you hear are likely to adhere to this four-beat form.
However, not all music has four beats per measure, and not every beat is equal
to a quarter note. To understand all the different numbers and types of beats
per measure, you need only to apply a little math—in the form of fractions.
Measuring the Beats
Written music uses something called a time signature to signify how many beats
are in a measure and what kind of note is used for the basic beat. A time signature
looks kind of like a fraction, with one number sitting on top of another
number. The top number indicates how many beats are in a measure; the bottom
number indicates the note value of the basic beat.
Time signatures show how beats are organized in a particular piece of music.
This organization is called meter, and time signatures are sometimes called
meter signatures.