Rhythm and Meter: Compound Time Signatures

In the last music theory lesson on rhythm and meter, we talked in detail about simple time, and introduced compound time. Now we’ll look more closely at compound time and learn the compound time signatures.

Compound Time Signatures

Simple time signatures are straight forward. The top number is how many beats there are per measure, the bottom number represents the note value that gets the beat, and the beat is divisible by two. Unfortunately, compound time is not that simple (pun intended). If you recall, compound time is where the beat is divided into three. There is no way to divide a beat into three parts with the available note values without introducing irregular beat divisions, such as triplets. Therefore, we must add a dot to the beat note value to be able to divide it into three, required for a compound meter.

Let’s compare a simple duple meter with a compound duple meter to demonstrate:

In 2/4, there are two beats per measure; the quarter note gets the beat and is divisible by two:

If we want the beat to be divisible by three, we must add a dot to the quarter note. There are still two beats per measure, but the dotted quarter note gets the beat. The problem, however, is that there is no number to represent the dotted quarter note. The graphic representation below expresses a compound duple time signature using an actual note symbol to represent the beat instead of a number. There are two dotted quarter notes per measure and the dotted quarter is divisible by 3.

I believe the time signature symbol above clearly represents a compound duple meter. Unfortunately, tradition has not favored this method of notating compound time signatures. The solution, then is to use the division of the beat as the bottom number. This makes the time signature 6/8:

There still are two beats per measure, and the dotted quarter note gets the beat. But, since there’s not a number available to represent the dotted quarter, we use the division of the beat (the eighth note) for the bottom number. Thus, the top number must now be six, since there are six eighth notes to a measure.

If this is confusing to you, you’re not alone. But all you need to remember when learning compound time signatures is that if the top number is 6, 9, or 12 it is always a compound meter. It doesn’t matter what the bottom number is. Now, because the beat is divisible by three, all you have to do is divide the 6, 9 or 12 by three to find if it is compound duple, compound triple, or compound quadruple. 6 divided by 3 is two. Therefore a time signature where the top number is six is always compound duple. When the top number is nine, it is always compound triple (9÷3=3); 12 is always compound quadruple (12÷3=4)

Following are examples of compound time signatures:

Compound Duple Time Signatures

Compound Triple

Compound Quadruple

Time signatures are a music notation convention that instruct the performer how to execute the rhythm and meter. And since there are numerous ways to notate the same sounding metric structure, they are wildly inconsistent in their usage. For the most part, you should be able to distinguish aurally between duple, triple and quadruple meters without seeing the written music. But it is impossible to know for sure what time signature is actually being used without seeing the score. At times it is even impossible to tell whether the meter is simple time or compound time. Here’s an illustration using the famous American song “Take Me Out to the Ball Game.”

The song is written in 3/4 (simple triple).

The song also can be notated in compound duple without changing the sound of the music:

You can hear the song as being in a simple triple meter (e.g., 3/4) at a fast tempo, or compound duple (e.g., 6/8) at a moderate tempo. In fact, the song often is sung at a fast enough tempo that it sounds more like compound duple than simple triple. In compound duple, each measure sounds like a beat, divisible by three, the measures being grouped in twos. Below is a video of Harry Caray leading “Take Me Out to the Ball Game” during the seventh-inning stretch of a Chicago Cubs baseball game. He begins by counting “uh-one, uh-two, uh-three….” I don’t know about Harry’s musical skills, and they are irrelevant to my point. But his counting out the beat beforehand indicates that he is intuitively hearing the song in a compound meter. Listen carefully; he counts “1-2-3″ but when the singing starts those beats are not the quarter note as the original score indicates, but the dotted quarter note as the renotated version above. Harry counts to three probably because someone told him the song was in three. But in reality, the way Harry is counting, “uh-three” is superfluous. According to the beat Harry gives at the start, he and the crowd are singing in a compound duple meter.