diff --git a/src/uix/eidos/MOTION_SERVICE_RFC.md b/src/uix/eidos/MOTION_SERVICE_RFC.md
index 5ef4ffd6a..59b77d0e6 100644
--- a/src/uix/eidos/MOTION_SERVICE_RFC.md
+++ b/src/uix/eidos/MOTION_SERVICE_RFC.md
@@ -755,13 +755,22 @@ percepción del componente **es** la cascada, no una firma genérica encima.
 | Modo                       | Ejemplo                               | Feedback                                                      |
 | -------------------------- | ------------------------------------- | ------------------------------------------------------------ |
 | **(a) sema sola**          | Button, Checkbox                      | la firma (`data-event-*`); sin coordinado                    |
-| **(b) coordinado solo**    | Reveal, Rail                          | la cascada; firma genérica silenciada (`channels: []`)       |
-| **(c) ambos compuestos**   | un coordinado con `channels:['haptic']` | la cascada (visual) + un tap háptico/sonido (otra modalidad) |
-
-El conflicto sólo existía en el **eje visual**; silenciar `channels: []` lo elimina, pero
-sound/haptic siguen disponibles (modo c). Es ortogonalidad **por modalidad**, no apagar sema —
-coherente con §10 (la firma cross-modal compone con la coordinación; el servicio no toca el engine
-de sema).
+| **(b) coordinado solo**    | Rail                                  | la cascada; firma genérica silenciada (`channels: []`)       |
+| **(c) ambos compuestos**   | Reveal (`open` con `channels:['sound']`) | la cascada (visual) + sonido `emerge` — el opt-out visual lo da eidos (ver nota) |
+
+El conflicto está en el **eje visual**, y silenciar `channels: []` lo elimina apagando TODO. El
+modo (c) —componer la cascada con sound/haptic— tiene un matiz **verificado en el engine**: el
+meta-canal visual estampa `data-event-*` **siempre que el evento tenga algún canal** (`channels ≠
+[]`), sin mirar _cuál_. Así que un coordinado con `channels: ['sound']` obtiene el sonido **y** la
+firma visual genérica (`present-rise`) — que pelearía con la cascada. **La solución vive en MOTION,
+no en sema** (sema queda intacto): eidos emite, junto a cada preset coordinado, una regla que
+**neutraliza su propia firma visual** sobre la superficie —
+`[data-animation-style='cascade-X'][data-event-phase='active'] { animation: none !important }`
+(`render-css.ts` → `renderCoordinatedPresetRules`). La firma usa `animation` → muere; la cascada es
+`transition` → sobrevive. Es **aditivo** (inerte hasta que un coordinado dispare un evento sema) y
+coherente con la doctrina: **eidos es el dueño del eje visual**, así que el opt-out de SU firma vive
+en eidos. Resultado: un coordinado declara `channels: ['sound']` y compone sonido + cascada, **sin
+tocar el engine de sema** (§10 sigue valiendo). Test en `eidos/motion.test.ts`.
 
 ### B.3 — Ejemplo con tokens: `Button` (modo a) y su composición (modo c)
 
diff --git a/src/uix/eidos/generated/base.css b/src/uix/eidos/generated/base.css
index 7834b3ee5..839bb6a77 100644
--- a/src/uix/eidos/generated/base.css
+++ b/src/uix/eidos/generated/base.css
@@ -5190,6 +5190,10 @@
 	transform: translateX(-16px);
 }
 
+[data-animation-style='cascade-slide'][data-event-phase='active'] {
+	animation: none !important;
+}
+
 [data-animation-style='cascade-fade'] {
 	transition: opacity var(--motion-cascade-duration, var(--duration-moderate)) var(--motion-cascade-ease, var(--ease-out));
 	transition-delay: calc(var(--motion-stagger-index, 0) * var(--motion-stagger-each, 0ms));
@@ -5203,6 +5207,10 @@
 	opacity: 0;
 }
 
+[data-animation-style='cascade-fade'][data-event-phase='active'] {
+	animation: none !important;
+}
+
 [data-animation-style='cascade-scale'] {
 	transition: opacity var(--motion-cascade-duration, var(--duration-moderate)) var(--motion-cascade-ease, var(--ease-out)), transform var(--motion-cascade-duration, var(--duration-moderate)) var(--motion-cascade-ease, var(--ease-out));
 	transition-delay: calc(var(--motion-stagger-index, 0) * var(--motion-stagger-each, 0ms));
@@ -5217,6 +5225,10 @@
 	transform: scale(0.9);
 }
 
+[data-animation-style='cascade-scale'][data-event-phase='active'] {
+	animation: none !important;
+}
+
 @media (forced-colors: active) {
 	:focus-visible {
 		outline: 2px solid Highlight;
diff --git a/src/uix/eidos/lib/render-css.ts b/src/uix/eidos/lib/render-css.ts
index ded174cc7..e2d33c832 100644
--- a/src/uix/eidos/lib/render-css.ts
+++ b/src/uix/eidos/lib/render-css.ts
@@ -765,7 +765,16 @@ function renderCoordinatedPresetRules(name: string, preset: CoordinatedPreset):
 		renderBlock(`${sel}[data-ending-style]`, [
 			'transition-delay: calc((var(--motion-stagger-count, 1) - 1 - var(--motion-stagger-index, 0)) * var(--motion-stagger-each, 0ms));'
 		]),
-		renderBlock(`${sel}[data-starting-style], ${sel}[data-ending-style]`, offDecls)
+		renderBlock(`${sel}[data-starting-style], ${sel}[data-ending-style]`, offDecls),
+		// A coordinated surface OPTS OUT of sema's generic VISUAL firma: if it ALSO fires a
+		// sema event (so `data-event-*` is stamped — the engine stamps it for any non-empty
+		// `channels`), the generic `present-rise`/`dismiss-fade` keyframe would fight the
+		// cascade. Neutralise it HERE — eidos owns the visual axis, so the opt-out lives in
+		// MOTION, never in sema. `animation: none` kills the firma's keyframe; the cascade is
+		// a `transition`, so it survives. `!important` because an intent-specific firma
+		// selector (3 attrs) outranks this 2-attr one. This is the modo (c) enabler: a
+		// coordinated component can compose sound/haptic with the cascade (RFC Apéndice B).
+		renderBlock(`${sel}[data-event-phase='active']`, ['animation: none !important;'])
 	]
 }
 
diff --git a/src/uix/eidos/motion.test.ts b/src/uix/eidos/motion.test.ts
index ce588c659..9f4308425 100644
--- a/src/uix/eidos/motion.test.ts
+++ b/src/uix/eidos/motion.test.ts
@@ -76,6 +76,20 @@ describe('eidos motion — CSS generation', () => {
 		expect(css).not.toContain("[data-animation-style='cascade-slide'][data-state=");
 	});
 
+	it('coordinated surfaces opt OUT of the sema visual firma (modo c enabler)', () => {
+		// If a coordinated surface ALSO fires a sema event, the engine stamps data-event-*
+		// and eidos's generic firma (present-rise…) would fight the cascade. eidos
+		// neutralises its OWN firma here — motion owns the visual axis, sema is untouched:
+		// animation:none kills the firma keyframe; the cascade is a transition, so it
+		// survives. This lets a coordinated component compose sound/haptic.
+		expect(css).toMatch(
+			/\[data-animation-style='cascade-slide'\]\[data-event-phase='active'\] \{\s*animation: none !important;/
+		);
+		for (const name of ['cascade-slide', 'cascade-fade', 'cascade-scale']) {
+			expect(css).toContain(`[data-animation-style='${name}'][data-event-phase='active'] {`);
+		}
+	});
+
 	it('emits the Material transition presets (shared-axis + fade-through)', () => {
 		expect(css).toContain(`[data-animation-style='shared-axis-x'][data-state='open']`);
 		expect(css).toContain(`[data-animation-style='shared-axis-y'][data-state='open']`);
diff --git a/src/uix/morfo/components/reveal.ts b/src/uix/morfo/components/reveal.ts
index da35882e7..2933a69f0 100644
--- a/src/uix/morfo/components/reveal.ts
+++ b/src/uix/morfo/components/reveal.ts
@@ -21,16 +21,16 @@ import { v } from '../types';
 export const revealMorfo = {
 	name: 'Reveal',
 	kebab: 'reveal',
-	// 'sema' because the morfo declares events (open/close) — they participate in the
-	// sema layer even though `channels: []` silences their perceptual surface.
 	scope: ['soma', 'sema'],
-	// The reveal's perception IS the coordinated cascade (eidos transitions on the
-	// Presence's data-starting/ending-style) — NOT a generic sema signature. So the
-	// open/close events carry `channels: []` (no perceptual surface) and expression is
-	// 'none': otherwise the generic emerge `present-rise`/`dismiss-fade` signature
-	// fires on the event and FIGHTS the coordinated motion (a real bug the demo hit).
-	// Doctrine: a coordinated-motion component silences the generic sema signal.
-	expression: 'none',
+	// Modo (c) — composición sema + motion (RFC Apéndice B). `open` declares
+	// `channels: ['sound']`: it PLAYS an `emerge` sound (sema) WHILE the coordinated
+	// cascade runs (motion). They don't fight because eidos NEUTRALISES its own generic
+	// VISUAL firma over coordinated surfaces (`render-css.ts`: `[data-animation-style][
+	// data-event-phase='active'] { animation: none !important }`) — the firma's keyframe
+	// dies, the cascade's `transition` survives. The opt-out lives in MOTION, never in
+	// sema. Both `open` and `close` declare `channels: ['sound']` — emerge sounds on
+	// appear AND on dismiss; eidos neutralises the visual firma either way (cascade survives).
+	expression: 'family-default',
 	apg: 'https://www.w3.org/WAI/ARIA/apg/patterns/disclosure/',
 	texts: {
 		label: '#?components.reveal.label|Reveal'
@@ -42,11 +42,12 @@ export const revealMorfo = {
 				family: 'emerge',
 				verb: 'open',
 				target: v.partRef('panel'),
-				// State is set in the soma handler → `post`, so a (future) perceptual
-				// hold never blocks the functional open (CLAUDE.md sequencing doctrine).
+				// State is set in the soma handler → `post`, so the perceptual hold never
+				// blocks the functional open (CLAUDE.md sequencing doctrine).
 				sequence: 'post',
-				// No perceptual surface — the coordinated cascade IS the feedback.
-				channels: []
+				// Modo (c): the sound plays WITH the cascade. eidos neutralises the generic
+				// VISUAL firma over the coordinated surface, so only sound + cascade land.
+				channels: ['sound']
 			}
 		},
 		{
@@ -56,7 +57,9 @@ export const revealMorfo = {
 				verb: 'close',
 				target: v.partRef('panel'),
 				sequence: 'post',
-				channels: []
+				// Modo (c) también al cerrar — emerge sounds on dismiss too (symmetry); the
+				// exit cascade (data-ending-style) runs while the visual firma is neutralised.
+				channels: ['sound']
 			}
 		}
 	],
diff --git a/web/routes/temas/animations/+layout.svelte b/web/routes/temas/animations/+layout.svelte
index a5ab8b467..1fb24b564 100644
--- a/web/routes/temas/animations/+layout.svelte
+++ b/web/routes/temas/animations/+layout.svelte
@@ -23,9 +23,11 @@
 
 	const uix = createActiveUix({
 		langs: { schema: { sium: siumLangs, secs: secsLangs }, defaultLocale: 'es' as const },
-		// Engine present so portal components (Dialog / Popover / Drawer) hydrate;
-		// sound + haptic off to keep the visual-motion demo quiet.
-		events: { sound: false, haptic: false }
+		// `sound: true` so the modo (c) demo (Reveal — RFC Apéndice B) is audible: opening
+		// the reveal plays an `emerge` sound WHILE the cascade runs (eidos neutralises the
+		// generic visual firma over the coordinated surface, so they compose, not fight).
+		// haptic stays off. The sound also makes each Button's contact press audible.
+		events: { sound: true, haptic: false }
 	})
 	setActiveUix(uix)
 	Soma.create()
diff --git a/web/routes/temas/animations/reveal/+page.svelte b/web/routes/temas/animations/reveal/+page.svelte
index cd09af698..1d0773413 100644
--- a/web/routes/temas/animations/reveal/+page.svelte
+++ b/web/routes/temas/animations/reveal/+page.svelte
@@ -69,6 +69,15 @@
 			(Panel + Items) como <code>data-animation-style</code> — se nombra una vez, el sistema sabe dónde
 			(RFC §5).
 		</p>
+		<p class="lede">
+			<strong>Modo (c) — compone sema + motion</strong> (RFC Apéndice B): al <strong>abrir y al
+			cerrar</strong>, los eventos declaran <code>channels: ['sound']</code> y suena un tono
+			<code>emerge</code> <strong>a la vez</strong> que corre la cascada. No pelean porque
+			<strong>eidos neutraliza su propia firma visual</strong> sobre las superficies coordinadas
+			(<code>animation: none</code> donde hay <code>data-animation-style</code> +
+			<code>data-event-phase</code>); la cascada es <code>transition</code> y sobrevive. El opt-out vive
+			en <strong>motion</strong>, sema intacto. (Sube el volumen; el audio arranca con el primer click.)
+		</p>
 		<div class="actions">
 			<div class="picker" role="group" aria-label="Estilo de animación">
 				{#each STYLES as s (s.value)}