diff --git a/lib/estado/estado_ecualizador.dart b/lib/estado/estado_ecualizador.dart
index c262bca..3d15a62 100644
--- a/lib/estado/estado_ecualizador.dart
+++ b/lib/estado/estado_ecualizador.dart
@@ -507,14 +507,29 @@ class EstadoEcualizador extends ChangeNotifier {
     return deviceId;
   }
 
+  /// Enables or disables the equalizer.
+  ///
+  /// Engine FIRST, disk last. The previous order persisted before telling the
+  /// engine, so two quick taps raced on a disk write: when the first write
+  /// resolved last, the engine received the FIRST tap's value after the second
+  /// one and the checkbox read enabled while the sound stayed flat. Issuing the
+  /// engine call before any `await` means overlapping taps reach the engine in
+  /// tap order, so the last tap always wins.
+  ///
+  /// Each step then re-checks [_activo]: a newer tap that landed mid-flight
+  /// owns the outcome, and this superseded call must not apply a preset or
+  /// persist a value the user has already changed their mind about.
   Future<void> cambiarActivo(bool activo) async {
     _activo = activo;
-    await servicio.guardarActivo(activo);
+    notifyListeners();
+
     await audio.setEcualizadorActivo(activo);
+    if (_activo != activo) return;
     if (activo) {
       await audio.aplicarPreset(_presetActual);
+      if (_activo != activo) return;
     }
-    notifyListeners();
+    await servicio.guardarActivo(activo);
   }
 
   Future<void> cambiarPreset(
diff --git a/test/estado/estado_ecualizador_test.dart b/test/estado/estado_ecualizador_test.dart
index b5dd8cb..39179ba 100644
--- a/test/estado/estado_ecualizador_test.dart
+++ b/test/estado/estado_ecualizador_test.dart
@@ -1543,6 +1543,31 @@ void main() {
   // builtin_speaker id collision + device removal
   // ---------------------------------------------------------------------------
 
+  group('EstadoEcualizador — cambiarActivo bajo toques rápidos', () {
+    test('el motor acaba en el estado que muestra la UI', () async {
+      // cambiarActivo persists BEFORE telling the engine, so two quick taps
+      // race on a disk write: if the first write resolves last, the engine
+      // receives the FIRST tap's value after the second one — the checkbox
+      // says on while the sound is off.
+      final servicio = _FakeEcualizadorGuardadoLento();
+      final audio = FakeServicioAudio();
+      final eq = EstadoEcualizador(audio: audio, servicio: servicio);
+      await eq.cargarPersistido();
+      audio.cambiosEcualizadorActivo.clear();
+
+      final primero = eq.cambiarActivo(false);
+      final segundo = eq.cambiarActivo(true);
+      await Future.wait([primero, segundo]);
+
+      expect(eq.activo, isTrue);
+      expect(
+        audio.cambiosEcualizadorActivo.last,
+        isTrue,
+        reason: 'the engine must end matching the state the UI shows',
+      );
+    });
+  });
+
   group('EstadoEcualizador — bonded Bluetooth names', () {
     const deviceId = 'bt_a2dp:AA:BB:CC:DD:EE:FF';
 
@@ -1704,6 +1729,24 @@ void main() {
   });
 }
 
+/// Fake whose [guardarActivo] stays pending until released, and releases the
+/// pending writes in REVERSE order — reproducing a disk write that resolves
+/// out of order between two quick taps.
+class _FakeEcualizadorGuardadoLento extends FakeServicioEcualizador {
+  int _llamadas = 0;
+
+  @override
+  Future<void> guardarActivo(bool activo) async {
+    // The FIRST write is the slow one: that is the ordering hazard, since an
+    // unserialized second tap overtakes it and the slow write's engine call
+    // lands last.
+    await Future<void>.delayed(
+      _llamadas++ == 0 ? const Duration(milliseconds: 20) : Duration.zero,
+    );
+    await super.guardarActivo(activo);
+  }
+}
+
 /// Fake whose [resubscribir] stays pending until [completarResubscribir]
 /// runs — creates the overlap window for the in-flight-guard test above.
 class _FakeDispositivoAudioResubscribirLento