8 INTRODUCTIONpiano, played by the left hand, consists of two notes per beat, while the upper
part, played by the right hand, subdivides the beat even further, into four notes
per beat.
Contrastingly, compound meters divide the beat into three equal parts.
Irish jigs display the “jiggety, jiggety” feeling of compound meter. The opening of
Aaron Copland’s “Morning on the Ranch” (LG 15.2) moves at a slower tempo than
a typical jig, but you should still be able to count along with its compound duple
meter: “one-and-a two-and-a, one-and-a two-and-a.” Notice that most phrases
begin with a pickup, and many beats are fi lled with two notes, one longer and
one shorter; the longer note fi lls two-thirds of the beat, the shorter note the
remaining third:a one-and- a two-and- a one-and- a two-and- aThe difference between simple and compound meters is generally easy to
hear, but an important exception may be found in the blues and in the many
musical genres that draw on the blues, including jazz, gospel, and rock and roll.
Characteristic of blues-related music is a shuffl e rhythm, in which the meter
is closer to compound than to simple: beats are often divided into three equal
notes, or into two unequal notes that are not quite in the 2:1 ratio of “Morning
on the Ranch.” The subtle feel of that shuffle, or swing. enlivens the rhythms
of “Walking Blues” (LG 14.1), West End Blues (LG 12.4), and “Talk about Jesus”
(LG 14.2).PITCH AND DYNAMICS
In scientifi c terms, a musical tone is created when a vibrating object (say, a gui-
tar string) excites the surrounding air particles, creating a sound wave. The char-
acteristics of that sound wave include its frequency, corresponding to how fast
the object is vibrating, and its amplitude, corresponding to how energetically
the object is vibrating—that is, how much distance it travels with each oscillation.
Our ears perceive frequency as pitch: the faster the vibration, the higher the fre-
quency and thus the higher the perceived pitch. A soprano’s vocal cords vibrate
faster than a bass’s; a violin’s strings vibrate faster than a cello’s. The more energ y
that is expended in those vibrations, the greater the amplitude and thus the louder
the volume or dynamics. An unplugged electric guitar can be played only at a low
dynamic, but plug it into an electronic amplifi er—thereby harnessing electricity to
energize the vibrations—and it can be deafening.
Altering the dynamic level can transform music’s effect. What would Sousa’s
Stars and Stripes Forever (LG 7.1) sound like if played at a whisper? Or what if that
military band gave a thunderous rendition of “Jeanie with the Light Brown Hair”
(LG 6.3)? Inappropriate dynamics can spoil the music.
Some music has an appropriate dynamic level that, once found, is sustained
with little variation throughout the piece. Chuck Berry’s 1957 song “School Day”
(LG 17.4) has very little dynamic contrast; the entire song is most effective when
played at a constant volume, preferably one that would annoy the parents of
1950s teenagers. Other music, though, exploits contrasting dynamic levels to
convey a variety of musical ideas. Even the boisterous Stars and Stripes Forever172028_00b_001-017_INTRO_r3_ko.indd 8 23/01/13 9:47 AM