Topic 1.7 Meter and Time Signature: interpret time signatures, identify the meter type, and relate the numbers to the beat and its division.

What this topic is asking

The College Board (Topic 1.7) wants you to read a time signature, determine the meter (simple or compound; duple, triple or quadruple), and relate the two numbers to the beat and its division, including the common-time and cut-time symbols.

Reading a simple time signature

A simple time signature has an upper number of 2, 3 or 4, because the beat divides into two and the measure groups two, three or four such beats. The lower number tells you which written value equals one beat.

Reading a compound time signature

Compound time signatures have an upper number of 6, 9 or 12, signalling that the lower-number values group into threes. Here the lower number names the division, not the beat:

• The beat is a dotted note made of three of the lower-number values.
• The number of beats equals the upper number divided by three.

So 6/8 is two dotted-quarter beats (6 divided by 3), 9/8 is three dotted-quarter beats, and 12/8 is four dotted-quarter beats. The dotted quarter is the beat because three eighths group into one dotted quarter.

Common time and cut time

Why compound signatures need grouping

The deepest point is that the time signature is a code for the metric hierarchy, and the code reads differently for simple and compound meters. In simple meter the lower number is generous enough to name the beat directly, because the beat divides into two equal halves that are themselves single note values. In compound meter the beat divides into three, and no single undotted value divides into three, so the lower number can only name the division; you recover the beat by grouping three divisions into a dotted note. This is why 6/8 is not "six beats": the listener feels two dotted-quarter pulses. Recognizing whether the upper number is grouping by twos (simple) or by threes (compound) is the skill that lets you count, conduct and notate any meter, and it connects directly to the simple-versus-compound division you learned in the previous topic.

A reliable reading procedure

Look first at the upper number. If it is 2, 3 or 4, the meter is simple: the upper number is the beat count and the lower number is the beat value. If it is 6, 9 or 12, the meter is compound: divide the upper number by three to get the beat count, group the lower-number values into threes to find the dotted beat, and remember each beat divides into three. Quintuple and septuple meters (such as 5/4 or 7/8) are usually treated as combinations of twos and threes, but the AP exam concentrates on the standard simple and compound signatures above.

Try this

Q1. What note value receives one beat in 2/2, and what is its common symbol? [2 points]

• Cue. The half note (two half-note beats per measure); 2/2 is written as cut time, a C with a vertical slash.

Q2. How many beats are in a measure of 9/8, and what is the beat value? [2 points]

• Cue. Three beats (9 divided by 3), each a dotted quarter note (compound triple).