docs(design): propose a multi-band Tone EQ

The clearest failure this exercise surfaced is a rack holding two Shape One
Range modules doing different jobs. A multi-band EQ answers it better than a
per-node role label would, because an author already understands it — bass,
middle, treble is the most widely used audio control there is.

Its bands can BE the shared vocabulary: three are Bass / Middle / Treble, five
open to Bass / Warmth / Middle / Clarity / Air. So using the EQ teaches the
words the rest of the rack relies on, rather than the vocabulary living only on
a ruler somebody has to go and read.

Built like the carve, not like a new effect. Carve already owns several tagged
nodes and presents as one module; an EQ does the same with `fromEq`. Three
bands are a low shelf, a peaking and a high shelf — all already shipping. There
is nothing new in the graph or the render, and the nodes stay ordinary, so an
author who opens the details finds the filters they could have added by hand.

That route also sidesteps a real constraint: the registry's parameter model is
flat key/value, so an `eq` effect TYPE with N bands would need array-shaped
params it does not support.

Drawn with vertical faders around a centre detent, because that is what an
equaliser looks like to everyone who has met one. Collapsed, it reads like
every other module — "Bass +3, Middle -2, Treble +2", or "Flat" when nothing
has been touched.

Design only; not built.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: vanceingalls

plans/audio-fx-ux/README.md

@@ -97,6 +97,35 @@ property print as their escape sequence on the page. This cost three rounds of
 chasing what looked like three unrelated rendering bugs. The template is a plain
 literal; keep it that way, and use HTML entities for typographic characters.
 
+## Proposed: a multi-band EQ ("Tone")
+
+The clearest failure this exercise surfaced is a rack holding two *Shape One
+Range* modules doing different jobs. A multi-band EQ is the answer, and it is a
+better one than a role label because an author already understands it: bass,
+middle, treble is the most widely used audio control there is.
+
+**Its bands can be the shared vocabulary.** Three bands are Bass / Middle /
+Treble; five open up to Bass / Warmth / Middle / Clarity / Air. So using the EQ
+teaches the words the rest of the rack relies on, instead of the vocabulary
+living only on a ruler somebody has to read.
+
+**Built like the carve, not like a new effect.** Carve already owns several
+tagged nodes and presents as one module (`fromCarve`, filtered out of the
+hand-built list). An EQ does the same with `fromEq`: three bands are a low
+shelf, a peaking and a high shelf — all effects that already ship. Nothing new
+in the render, nothing new in the graph, and the nodes stay ordinary, so an
+author who opens the details finds exactly the filters they could have added by
+hand.
+
+The registry's parameter model is flat key/value, so an `eq` effect *type* with
+N bands would need array-shaped params it does not support. The composite-module
+route avoids that entirely and is the pattern this codebase already proved.
+
+Faders rather than sliders, because a row of vertical faders around a centre
+detent is what an equaliser looks like to everyone who has met one. Collapsed,
+it reads like every other module: "Bass +3, Middle −2, Treble +2", or "Flat"
+when nothing has been touched.
+
 ## What still needs deciding
 
 - Does the plain name **replace** the DSP name or sit beside it? Replacing is