  We investigate correlations among pitches in several songs and pieces of
piano music by mapping them to one-dimensional walks. Two kinds of correlations
are studied, one is related to the real values of frequencies while they are
treated only as different symbols for another. Long-range power law behavior is
found in both kinds. The first is more meaningful. The structure of music, such
as beat, measure and stanza, are reflected in the change of scaling exponents.
Some interesting features are observed. Our results demonstrate the viewpoint
that the fundamental principle of music is the balance between repetition and
contrast.
