Scales and Key

Rock is generally assumed to be “tonal,” meaning that every song has a tonal center around which other pitches are organized. A wide variety of scale structures have been proposed for rock; the current chapter takes a corpus-based approach to this issue. It is proposed that rock as a whole uses a global scale containing all twelve scale degrees except for flat-2 and sharp-4—the “supermode.” Individual songs tend to use subsets of this scale; most often these subsets are “compact,” containing a set of adjacent scale degrees on the line of fifths. Further analysis shows that scales in rock songs reflect something like the major/minor distinction of classical music, but with significant differences. The identification of key in rock seems to rely on the distribution of pitch classes, the emphasis of melodic tones, and the metrical placement of harmonies.