An Introduction to America’s Music

14 INTRODUCTION

Scales, as we have seen, can be thought of as patterns of intervals—whole steps

and half steps, in the case of diatonic scales. All of these patterns can be built

using as a starting point, or tonic, any one of the twelve semitones that divide

the octave. Because of Historical Reasons Too Complicated to Explain, musicians

label these twelve pitches using the fi rst seven letters of the alphabet, adding

“sharp” or “fl at” to any of those letters to complete the set, for example, “C,” “G,”

“B fl at,” “F sharp.” Any piece of tonal music can thus be identifi ed by naming

which of the twelve possible notes it uses as its tonic; a piece based on the pitch D

is said to be in the key of D. In classical music, the name of a piece often includes

which diatonic scale it is based on; for example, a symphony may be in C minor,

or a string quartet in E-fl at major.

Just as the tonic functions as “home” for all the notes in a scale, a key

may function as “home” in a piece of music that travels through several keys.

The movement from one key to another—modulation—can create powerful

musical effects. The moment in Sousa’s Stars and Stripes Forever (LG 7.1) where

the dynamic drops down to a soft level is also a moment where the music

modulates from the “home” key to a lower key, increasing the sense of relax-

ation at this point in the march. Conversely, the New England contra dance

musicians who play “Money Musk” (LG 2.2) raise the tune to a higher key

after a few repetitions (at 1:37), injecting new energ y into their performance.

Harmony

Very little of the music you have been listening to so far consists of melody and

nothing else. Most music combines multiple voices or instruments, or uses

instruments capable of sounding several pitches simultaneously, such as guitar

or piano. The art of harmony involves combining pitches into simultaneities, or

chords, and moving from one chord to the next to create chord progressions,

or, in jazz lingo, changes.

An essential concept here is that of consonance and dissonance. A consonant

chord is pleasing and harmonious to the ear, while a dissonant chord is harsh and

unsettled. Most music mixes consonance and dissonance to create fl uctuating

levels of tension and relaxation. Dissonant combinations of pitches are legion;

any toddler capable of reaching up to a piano keyboard will discover countless

dissonances and play them with glee. Creating consonances, and mixing them

with other consonances and just the right amount of dissonance to create pleas-

ing chord progressions, requires considerably more craft.

The basic harmonic building block of tonal music is the three-note chord,

or triad, consisting of a starting pitch or root and the pitches a third and a fi fth

higher. This combination occurs naturally in the overtone series, where the

CDEFGABCDEFGABCDEFGAB

K The pitches of the fi rst

six partials as found on the

piano’s keyboard.

172028_00b_001-017_INTRO_r3_ko.indd 14 23/01/13 9:47 AM