It follows that the acoustically consonant chords of traditional Western music can
be connected by efficient voice leading. Acoustic consonance is incompletely understood;
however, theorists have long agreed that chords approximating a few consecutive elements
of the harmonic series are particularly consonant, at least when played with harmonic tones
(21). Since elements n to 2n of the harmonic series evenly divide an octave in frequency
space, they divide the octave nearly evenly in log-frequency space. These chords are
therefore clustered near the center of the orbifolds (Table 1), and can typically be linked by
efficient, independent voice leadings. Traditional tonal music exploits this possibility (Fig.
1A-C, Movie S4). This central feature of Western counterpoint is made possible by
composers’ interest in the harmonic property of acoustic consonance.