Autocorrelation gives complex sounds a collective summary property, analogous to molecular mass and charge.

Evidence

Autocorrelation provides a key summary of even very complex sounds. Earlier, we called the sinusoid the atom of sound, and complex sounds, comprising many sinusoids, we called the molecules of sound. Molecules have collective or lumped properties such as mass and electrical charge, which are useful, even critical, aggregate effects. Autocorrelation for complex sounds plays an analogous role as a critically useful aggregate piece of information about the whole. — Eric J. Heller, Why You Hear What You Hear- An…, 357

Categorization

• XREF: Extends the atom/molecule-of-sound framework from earlier chapters into a lumped-property analogy.