Amplitude adjustment does not change a mode’s characteristic shape

Evidence

The way we define shape, pulling the stalk higher or even (with the phase stalks) making the beads go below the line, does not change the shape; rather, this is changing the amplitude of the mode. Each mode has a unique shape. — Eric J. Heller, Why You Hear What You Hear- An…, 780

Categorization

• DEFINE: Distinguishes the mode’s shape (invariant) from its amplitude (variable) — a key conceptual separating line in normal-mode theory.