The Complete Idiot''s Guide to Music Theory

Time Signature
Beats per Measure
Half Time
If you move the other direction from the basic quarter-note time signature, you
get into time signatures based on a half-note beat. In a half-note time signature,
each half note gets one beat; quarter notes get half a beat, and eighth notes get
a quarter of a beat. Whole notes, on the other hand, get just two beats. (It’s not
really that confusing; it’s just more math to deal with.)
Half-note beats—2/2, 3/2, and the like—are typically used in classical music for
slower, more sweeping passages.
The following table presents the most common half-note beats.
Half-Note Time Signatures
Time Signature
Beats per Measure
Don’t assume that an eighth-note time signature is automatically twice as
fast as a quarter-note time signature. Although this might be true (and almost
always is true when time signatures change in the middle of a song), the speed
of the beat (what musicians call 
tempo
) is independent of the time signature.
Thus, a song in 3/8 time actually could be played slower than a song in 3/4.
(Learn more about tempo in Chapter 7.)
Warning

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Part 2:
Rhythms
72
Just as 4/4 is sometimes called common time, 2/2 is sometimes called 
cut time.
You can indicate 2/2 by either the normal time signature, or by a large C with a
line through it, like this:
2/2 time is cut-time—thus you cut a “C” in half.
Changing the Time
You always indicate the time signature at the very beginning of a piece of music.
However, you don’t have to keep the same time signature through the entire
song; you can change time anywhere you want in a piece of music; even for just
a measure or two!
If the meter changes in the middle of a song, you insert a new time signature at
the point of change. This new time signature remains in effect through the rest
of the song, or until another new time signature is introduced.
Here’s what a time change looks like in the middle of a piece of music:
In most music nota-
tion, the time signa-
ture is shown only
on the first line of
music (or when there’s a
time change)—unlike the
key signature, which is
typically shown at the start
of each line.
Tip
Changing time signatures in the middle of a song.
Grouping the Beats
If you see a piece of music in 9/8 and despair about counting that high (nine’s a
lot higher than four), there’s a way around the problem. You can do as many
musicians do: Chop up each measure into smaller groupings.
When you’re playing in odd time signatures—especially those with more than
four beats per measure—it’s common to subdivide the beats within a measure
into an easier-to-grasp pattern. Using smaller groupings not only makes each
measure easier to count; it also makes the music flow better. When you sub-
divide measures in this fashion, you create sub-rhythms behind the basic beat,
which makes the music easier to listen to.
For example, if you’re playing in 6/8 time, you could count all the beats evenly
(one, two, three, four, five, six)—or you could subdivide the beat. The most
common subdivision of 6/8 divides the measure into two equal parts, each con-
taining three beats, like this:

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Chapter 6:
Time Signatures
Subdividing a 6/8 measure into two groups of three.
So you count the measure “one two three; one two three,” or “one lah lay, two
lah lay.” Easier, isn’t it?
Of course, you could also divide 6/8 into three groups of two, or one group of
four and one group of two, or one group of one and one group of five, but the
two groups of three is the most common way to play this particular time signa-
ture.
For another example, let’s look at 5/4 time. In 5/4, measures are typically sub-
divided into one group of three and one group of two, like this:
73
Subdividing 5/4 time into one group of three and one group of two.
You count each measure “one, two, three; one, two.”
Of course, you could also reverse the groupings, and end up with two beats in the
first group and three beats in the second—“one, two; one, two, three.” It depends
on the feel and the flow of the music.
The more beats you have in a measure, the more possible groupings you can come
up with. To demonstrate, the following example shows three possible groupings of
7/4 time—4+3, 3+4, and 2+3+2.
Three different ways to group 7/4 time.
Just for fun, count all the way up to eleven, and see how many groupings you can
come up with for a measure of 11/4!
The Least You Need to Know
◆
You have to place a time signature at the beginning of a piece of music—or
anywhere you change the basic meter or time.
◆
The top number in a time signature indicates the number of beats per measure.
◆
The bottom number in a time signature indicates what note is used for the
basic beat.
◆
Odd time signatures are sometimes broken up into smaller groupings, to
make each measure easier to count.

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