Fundamentals vs overtones: the mixing distinction that actually pays rent

Every periodic sound you mix — voice, bass, synth, guitar, piano — is a root plus overtones. The fundamental is the lowest partial, the one that names the note. Overtones are the rest of the stack. Harmonics are the overtones that fall on integer multiples of the root. Inharmonic partials (bells, cymbals, some distorted guitars) do not. RootEQ’s grid is built for the harmonic case. It will not magically map a cymbal’s splash.

Weight, pitch, and edge

As a working approximation:

• Weight / boom / “chest” sits at the fundamental and the first octave.
• Pitch identity — the thing that lets you sing the note back — is distributed across the lower harmonics, not owned by the root alone.
• Presence / diction / pick noise / buzz lives higher in the series, often around 3×–9× depending on the instrument.
• Harshness / sibilance / fizz is often a high partial that is related to the note, which is why a static 6 kHz shelf hits every syllable, and a harmonic cut on the actual ringing partial hits the offending ones harder.

This is why a vocal can be loud and still unintelligible (too much fundamental, not enough 2–4 kHz family), and why a “presence boost” can make the same vocal painful (you boosted a whistling partial instead of the formant family).

How RootEQ encodes that distinction

The root node is the fundamental you chose. Grid bands are the overtones of that root, spaced by the selected prime. You can boost the root for weight, leave it, or cut it, without losing the lattice that carries pitch. If a single overtone starts to need its own life — a fifth that wants a different Q, or a harmonic that should become a new musical center — you promote that grid band into a new root. The original root stays. The new one grows its own grid. That is the tree.

Maximum eight roots, ten grid bands each, ±24 dB, Q from 0.1 to 20. Those are real limits. If your problem is a broadband tilt, a shelf on a conventional EQ is still the right object. If your problem is “this note’s family,” plant the note.