Meter involves the way multiple pulse layers work together to organize music in time. Standard meters in Western music can be classified into simple meters and compound meters, as well as duple, triple, and quadruple meters.

Duple, triple, and quadruple classifications result from the relationship between the counting pulse and the pulses that are slower than the counting pulse. In other words, it is a question of grouping: how many beats occur in each bar. If counting-pulse beats group into twos, we have duple meter; groups of three, triple meter; groups of four, quadruple meter. Conducting patterns are determined based on these classifications.

Simple and compound classifications result from the relationship between the counting pulse and the pulses that are faster than the counting pulse. In other words, it is a question of division: does each beat divide into two equal parts, or three equal parts. Meters that divide the beat into two equal parts are simple meters; meters that divide the beat into three equal parts are compound meters.

Thus, there are six types of standard meter in Western music:

• simple duple (beats group into two, divide into two)
• simple triple (beats group into three, divide into two)
• simple quadruple (beats group into four, divide into two)
• compound duple (beats group into two, divide into three)
• compound triple (beats group into three, divide into three)
• compound quadruple (beats group into four, divide into three)

In a time signature, the top number (and the top number only!) describes the type of meter. Following are the top numbers that always correspond to each type of meter:

• simple duple: 2
• simple triple: 3
• simple quadruple: 4
• compound duple: 6
• compound triple: 9
• compound quadruple: 12

Notating meter

In simple meters, the bottom number of the time signature corresponds to the type of note corresponding to a single beat. If a simple meter is notated such that each quarter note corresponds to a beat, the bottom number of the time signature is 4. If a simple meter is notated such that each half note corresponds to a beat, the bottom number of the time signature is 2. If a simple meter is notated such that each eighth note corresponds to a beat, the bottom number of the time signature is 8. And so on.

In compound meters, the bottom number of the time signature corresponds to the type of note corresponding to a single division of the beat. If a compound meter is notated such that each dotted-quarter note corresponds to a beat, the eighth note is the division of the beat, and thus the bottom number of the time signature is 8. If a compound meter is notated such that each dotted-half note corresponds to a beat, the quarter note is the division of the beat, and thus the bottom number of the time signature is 4. Note that because the beat is divided into three in a compound meter, the beat is always three times as long as the division note, and the beat is always dotted.

Hearing meter

For a more detailed explanation of meter with an emphasis on hearing and recognizing standard meters, see the following two videos:

Meter - counting pulse from Kris Shaffer on Vimeo.

Meter - grouping and division from Kris Shaffer on Vimeo.

Following are the musical examples referenced in the above videos:

"Come Out Clean," Jump Little Children

"With or Without You," U2

"The Tourist," Radiohead

Examples

Simple duple meter

Symphony No. 5, Movement IV., Ludwig van Beethoven

"Idioteque," Radiohead

Sonata No. 1 in F Minor, Op. 2, No. 1, Movement I., Ludwig van Beethoven

Simple triple meter

String Quartet No. 15 in D Minor, K. 421, Movement III., Wolfgang A. Mozart

Symphony No. 90 in C Major, Hob: I:90, Movement III., Joseph Haydn

Simple quadruple meter

"With or Without You," U2

"Come Out Clean," Jump Little Children

"Shh," Imogen Heap

Compound duple meter

"Shiver," Radiohead

Strong Quartet No. 17 in B-flat Major, K. 458, "The Hunt," Movement I., Wolfgang A. Mozart

Compound triple meter

"The Tourist," Radiohead

Sonata No. 42 in G Major, Hob. XVI:27, Movement II., Joseph Haydn

Compound quadruple meter

"Exogenesis: Symphony Part 3," Muse

Sonata No. 14 in C-sharp Minor, Op. 27, No. 2, "Moonlight," Movement I., Ludwig van Beethoven

St. Matthew Passion, No. 1, Chorus, "Kommt, ihr Töchter, helft mir klagen," J.S. Bach