Negative echoes suppress power near zero frequency, creating missing spectral peaks

Evidence

At zero frequency, the cosine is one at all times. The negative first return echo destructively interferes with the positive signal at time zero, resulting in a proximity antiresonance—a suppression of power near zero frequency. Since the fundamental frequency is f/2, but the peak spacing is f, we see that peaks at the even multiples of f/2: f = 2f/2, 2 f = 4f/2, and so on, are “missing.” — Eric J. Heller, Why You Hear What You Hear- An…, 1098

Categorization

• QUESTION: This explains missing even-multiple harmonics — worth connecting to how instrument overtones actually work.