feat: Add equalizer plugin with presets (e.g. bass booster) (#2575)

src/plugins/equalizer/presets.ts

@@ -0,0 +1,18 @@
+export const defaultPresets = ['bass-booster'] as const;
+export type Preset = (typeof defaultPresets)[number];
+
+export type FilterConfig = {
+  type: BiquadFilterType;
+  frequency: number;
+  Q: number;
+  gain: number;
+};
+
+export const presetConfigs: Record<Preset, FilterConfig> = {
+  'bass-booster': {
+    type: 'lowshelf',
+    frequency: 80,
+    Q: 100,
+    gain: 12.0,
+  },
+};