diff --git a/docs/ACCESSIBILITY.md b/docs/ACCESSIBILITY.md
index f9bd7816..4bde6783 100644
--- a/docs/ACCESSIBILITY.md
+++ b/docs/ACCESSIBILITY.md
@@ -38,6 +38,7 @@ Use **assertive** only for urgent errors or time-sensitive status.
 
 - Give the primary `<main>` a stable id such as `main-content` so skip links and **Alt+M** work everywhere. There should be **exactly one** `<main>` (or `role="main"`) per view.
 - For horizontal toolbars, add `data-roving-root` on the toolbar container. **Left/Right arrow** moves among buttons, links, tabs, and elements marked with `data-roving-item` (including those using `tabindex="-1"` for roving patterns).
+- Rich post editors should expose a named multiline textbox, a named formatting toolbar with pressed states, and helper text connected through `aria-describedby`. Post composer message lists should use `role="log"` with polite updates so new discussion activity is announced without interrupting the current task.
 
 ## What automation does _not_ prove
 
diff --git a/src/app/components/messaging/MessageComposer.tsx b/src/app/components/messaging/MessageComposer.tsx
index 2a64e86f..8baef1e5 100644
--- a/src/app/components/messaging/MessageComposer.tsx
+++ b/src/app/components/messaging/MessageComposer.tsx
@@ -1,6 +1,6 @@
 'use client';
 
-import { useState, useRef, useCallback } from 'react';
+import { useState, useRef, useCallback, useId } from 'react';
 import { FiSend, FiPaperclip, FiX, FiFile, FiImage, FiFileText } from 'react-icons/fi';
 import RichTextEditor from '@/app/components/ui/RichTextEditor';
 
@@ -39,6 +39,7 @@ export default function MessageComposer({
 }: MessageComposerProps) {
   const [content, setContent] = useState('');
   const fileInputRef = useRef<HTMLInputElement>(null);
+  const editorHelpId = useId();
 
   const handleContentChange = useCallback(
     (newContent: string) => {
@@ -161,6 +162,8 @@ export default function MessageComposer({
               content={content}
               onChange={handleContentChange}
               placeholder="Type your message..."
+              ariaLabel="Message content"
+              describedBy={editorHelpId}
             />
           </div>
 
@@ -182,7 +185,7 @@ export default function MessageComposer({
         </div>
 
         {/* Helper Text */}
-        <p className="text-[10px] text-gray-400 dark:text-gray-500 mt-2 ml-12">
+        <p id={editorHelpId} className="text-[10px] text-gray-400 dark:text-gray-500 mt-2 ml-12">
           Press{' '}
           <kbd className="px-1 py-0.5 bg-gray-100 dark:bg-gray-800 rounded text-[10px] font-mono">
             Enter
diff --git a/src/app/components/social/GroupDiscussionThread.tsx b/src/app/components/social/GroupDiscussionThread.tsx
index de92ff7d..56e4fe49 100644
--- a/src/app/components/social/GroupDiscussionThread.tsx
+++ b/src/app/components/social/GroupDiscussionThread.tsx
@@ -1,6 +1,6 @@
 'use client';
 
-import React, { useMemo, useState, useEffect, useRef } from 'react';
+import React, { useMemo, useState, useEffect, useRef, useId } from 'react';
 import { motion, AnimatePresence } from 'framer-motion';
 import { Paperclip, Send } from 'lucide-react';
 import RichTextEditor from '@/app/components/ui/RichTextEditor';
@@ -26,6 +26,7 @@ export default function GroupDiscussionThread({ messages, onPost }: GroupDiscuss
   const [files, setFiles] = useState<File[]>([]);
   const messagesEndRef = useRef<HTMLDivElement>(null);
   const fileInputRef = useRef<HTMLInputElement>(null);
+  const editorHelpId = useId();
 
   const attachments = useMemo<Attachment[]>(
     () =>
@@ -56,37 +57,60 @@ export default function GroupDiscussionThread({ messages, onPost }: GroupDiscuss
     }
   };
 
+  const handleEditorKeyDown = (event: React.KeyboardEvent<HTMLDivElement>) => {
+    if ((event.metaKey || event.ctrlKey) && event.key === 'Enter') {
+      event.preventDefault();
+      handlePost();
+    }
+  };
+
   return (
     <div className="flex flex-col h-full max-h-[600px] bg-white dark:bg-gray-800 rounded-lg border border-gray-200 dark:border-gray-700">
-      <div className="flex-1 overflow-y-auto space-y-4 p-4">
+      <div
+        className="flex-1 overflow-y-auto space-y-4 p-4"
+        role="log"
+        aria-label="Discussion messages"
+        aria-live="polite"
+        aria-relevant="additions text"
+      >
         {messages.length === 0 ? (
-          <div className="text-center py-8 text-gray-500 dark:text-gray-400">
+          <div className="text-center py-8 text-gray-500 dark:text-gray-400" role="status">
             <p className="text-sm">No messages yet. Start the conversation!</p>
           </div>
         ) : (
           <AnimatePresence>
             {messages.map((m, index) => (
-              <motion.div
+              <motion.article
                 key={m.id}
                 initial={{ opacity: 0, y: 10 }}
                 animate={{ opacity: 1, y: 0 }}
                 transition={{ delay: index * 0.05 }}
                 className="flex items-start gap-3 group"
+                aria-labelledby={`message-${m.id}-sender`}
               >
                 {/* Avatar */}
-                <div className="flex-shrink-0 w-10 h-10 rounded-full bg-purple-100 dark:bg-purple-900/30 border-2 border-white dark:border-gray-700 flex items-center justify-center text-sm font-medium text-purple-600 dark:text-purple-400">
+                <div
+                  className="flex-shrink-0 w-10 h-10 rounded-full bg-purple-100 dark:bg-purple-900/30 border-2 border-white dark:border-gray-700 flex items-center justify-center text-sm font-medium text-purple-600 dark:text-purple-400"
+                  aria-hidden="true"
+                >
                   {getInitials(m.senderName)}
                 </div>
 
                 {/* Message Content */}
                 <div className="flex-1 min-w-0">
                   <div className="flex items-center gap-2 mb-1">
-                    <span className="text-sm font-medium text-gray-900 dark:text-gray-50">
+                    <span
+                      id={`message-${m.id}-sender`}
+                      className="text-sm font-medium text-gray-900 dark:text-gray-50"
+                    >
                       {m.senderName}
                     </span>
-                    <span className="text-xs text-gray-500 dark:text-gray-400">
+                    <time
+                      className="text-xs text-gray-500 dark:text-gray-400"
+                      dateTime={new Date(m.createdAt).toISOString()}
+                    >
                       {formatDistanceToNow(new Date(m.createdAt), { addSuffix: true })}
-                    </span>
+                    </time>
                   </div>
                   <div
                     className="prose prose-sm dark:prose-invert max-w-none text-gray-700 dark:text-gray-300 bg-gray-50 dark:bg-gray-700/50 rounded-lg p-3"
@@ -109,7 +133,7 @@ export default function GroupDiscussionThread({ messages, onPost }: GroupDiscuss
                     </div>
                   )}
                 </div>
-              </motion.div>
+              </motion.article>
             ))}
           </AnimatePresence>
         )}
@@ -117,8 +141,23 @@ export default function GroupDiscussionThread({ messages, onPost }: GroupDiscuss
       </div>
 
       {/* Message Input */}
-      <div className="border-t border-gray-200 dark:border-gray-700 p-4 space-y-3 bg-gray-50 dark:bg-gray-900/50">
-        <RichTextEditor content={content} onChange={setContent} placeholder="Share an update..." />
+      <form
+        className="border-t border-gray-200 dark:border-gray-700 p-4 space-y-3 bg-gray-50 dark:bg-gray-900/50"
+        onSubmit={(event) => {
+          event.preventDefault();
+          handlePost();
+        }}
+        aria-label="Create discussion post"
+      >
+        <div onKeyDown={handleEditorKeyDown}>
+          <RichTextEditor
+            content={content}
+            onChange={setContent}
+            placeholder="Share an update..."
+            ariaLabel="Discussion post content"
+            describedBy={editorHelpId}
+          />
+        </div>
         <div className="flex items-center justify-between">
           <label className="inline-flex items-center gap-2 text-sm text-gray-600 dark:text-gray-400 cursor-pointer hover:text-purple-600 dark:hover:text-purple-400 transition-colors">
             <Paperclip size={16} />
@@ -128,6 +167,7 @@ export default function GroupDiscussionThread({ messages, onPost }: GroupDiscuss
               type="file"
               className="hidden"
               multiple
+              aria-label="Attach files to discussion post"
               onChange={(e) => {
                 const fl = Array.from(e.target.files || []);
                 setFiles((prev) => [...prev, ...fl]);
@@ -135,9 +175,9 @@ export default function GroupDiscussionThread({ messages, onPost }: GroupDiscuss
             />
           </label>
           <button
-            onClick={handlePost}
             disabled={!content || content === '<p></p>' || content.trim() === ''}
             className="px-4 py-2 rounded-md bg-purple-600 hover:bg-purple-700 disabled:bg-gray-300 disabled:cursor-not-allowed text-white text-sm font-medium transition-colors flex items-center gap-2"
+            type="submit"
           >
             <Send size={16} />
             Post
@@ -155,8 +195,10 @@ export default function GroupDiscussionThread({ messages, onPost }: GroupDiscuss
               >
                 {file.name}
                 <button
+                  type="button"
                   onClick={() => setFiles(files.filter((_, i) => i !== index))}
                   className="hover:text-purple-900 dark:hover:text-purple-100"
+                  aria-label={`Remove ${file.name}`}
                 >
                   ×
                 </button>
@@ -164,8 +206,10 @@ export default function GroupDiscussionThread({ messages, onPost }: GroupDiscuss
             ))}
           </div>
         )}
-        <p className="text-xs text-gray-500 dark:text-gray-400">Press Cmd/Ctrl + Enter to post</p>
-      </div>
+        <p id={editorHelpId} className="text-xs text-gray-500 dark:text-gray-400">
+          Press Cmd/Ctrl + Enter to post
+        </p>
+      </form>
     </div>
   );
 }
diff --git a/src/app/components/social/__tests__/GroupDiscussionThread.test.tsx b/src/app/components/social/__tests__/GroupDiscussionThread.test.tsx
index e9a92ecb..fae40846 100644
--- a/src/app/components/social/__tests__/GroupDiscussionThread.test.tsx
+++ b/src/app/components/social/__tests__/GroupDiscussionThread.test.tsx
@@ -3,8 +3,24 @@ import { describe, it, expect, vi } from 'vitest';
 
 // Mock the RichTextEditor to avoid TipTap dependency in tests
 vi.mock('@/app/components/ui/RichTextEditor', () => ({
-  default: ({ content, onChange }: { content: string; onChange: (v: string) => void }) => (
-    <textarea data-testid="rte" value={content} onChange={(e) => onChange(e.target.value)} />
+  default: ({
+    content,
+    onChange,
+    ariaLabel,
+    describedBy,
+  }: {
+    content: string;
+    onChange: (v: string) => void;
+    ariaLabel?: string;
+    describedBy?: string;
+  }) => (
+    <textarea
+      aria-label={ariaLabel}
+      aria-describedby={describedBy}
+      data-testid="rte"
+      value={content}
+      onChange={(e) => onChange(e.target.value)}
+    />
   ),
 }));
 
@@ -16,8 +32,30 @@ describe('GroupDiscussionThread', () => {
     render(<GroupDiscussionThread messages={[]} onPost={onPost} />);
 
     fireEvent.change(screen.getByTestId('rte'), { target: { value: '<p>Hello</p>' } });
-    fireEvent.click(screen.getByText('Post'));
+    fireEvent.click(screen.getByRole('button', { name: 'Post' }));
 
     expect(onPost).toHaveBeenCalledWith('<p>Hello</p>', undefined);
   });
+
+  it('labels the post form, editor, and message log for assistive tech', () => {
+    render(<GroupDiscussionThread messages={[]} onPost={vi.fn()} />);
+
+    expect(screen.getByRole('log', { name: 'Discussion messages' })).toBeInTheDocument();
+    expect(screen.getByRole('form', { name: 'Create discussion post' })).toBeInTheDocument();
+    expect(screen.getByRole('textbox', { name: 'Discussion post content' })).toHaveAccessibleDescription(
+      'Press Cmd/Ctrl + Enter to post',
+    );
+    expect(screen.getByRole('status')).toHaveTextContent('No messages yet');
+  });
+
+  it('posts content with the documented keyboard shortcut', () => {
+    const onPost = vi.fn();
+    render(<GroupDiscussionThread messages={[]} onPost={onPost} />);
+
+    const editor = screen.getByRole('textbox', { name: 'Discussion post content' });
+    fireEvent.change(editor, { target: { value: '<p>Keyboard post</p>' } });
+    fireEvent.keyDown(editor, { key: 'Enter', ctrlKey: true });
+
+    expect(onPost).toHaveBeenCalledWith('<p>Keyboard post</p>', undefined);
+  });
 });
diff --git a/src/app/components/ui/RichTextEditor.tsx b/src/app/components/ui/RichTextEditor.tsx
index f4d5f369..73fc3d0e 100644
--- a/src/app/components/ui/RichTextEditor.tsx
+++ b/src/app/components/ui/RichTextEditor.tsx
@@ -4,19 +4,27 @@ import { useEditor, EditorContent } from '@tiptap/react';
 import StarterKit from '@tiptap/starter-kit';
 import Placeholder from '@tiptap/extension-placeholder';
 import { Bold, Italic, List, ListOrdered, Code, Strikethrough } from 'lucide-react';
-import { useEffect } from 'react';
+import { useEffect, useId } from 'react';
+import type { ReactNode } from 'react';
 
 interface RichTextEditorProps {
   content: string;
   onChange: (content: string) => void;
   placeholder?: string;
+  ariaLabel?: string;
+  describedBy?: string;
 }
 
 export default function RichTextEditor({
   content,
   onChange,
   placeholder = 'Type your message...',
+  ariaLabel = 'Post editor',
+  describedBy,
 }: RichTextEditorProps) {
+  const editorId = useId();
+  const toolbarId = `${editorId}-toolbar`;
+
   const editor = useEditor({
     extensions: [
       StarterKit,
@@ -32,6 +40,12 @@ export default function RichTextEditor({
     },
     editorProps: {
       attributes: {
+        role: 'textbox',
+        'aria-label': ariaLabel,
+        'aria-describedby': [describedBy, toolbarId].filter(Boolean).join(' '),
+        'aria-multiline': 'true',
+        'aria-placeholder': placeholder,
+        spellcheck: 'true',
         class:
           'prose prose-sm dark:prose-invert focus:outline-none max-w-none min-h-[44px] text-sm',
       },
@@ -58,7 +72,7 @@ export default function RichTextEditor({
     isActive: boolean;
     onClick: () => void;
     label: string;
-    children: React.ReactNode;
+    children: ReactNode;
   }) => (
     <button
       onClick={onClick}
@@ -68,6 +82,8 @@ export default function RichTextEditor({
           : 'hover:bg-gray-100 dark:hover:bg-gray-700 text-gray-500 dark:text-gray-400 hover:text-gray-700 dark:hover:text-gray-300'
       }`}
       aria-label={label}
+      aria-pressed={isActive}
+      title={label}
       type="button"
     >
       {children}
@@ -77,7 +93,12 @@ export default function RichTextEditor({
   return (
     <div className="border border-gray-200 dark:border-gray-700 rounded-xl bg-white dark:bg-gray-800 overflow-hidden transition-all duration-200 focus-within:ring-2 focus-within:ring-violet-500/30 focus-within:border-violet-300 dark:focus-within:border-violet-700">
       {/* Toolbar */}
-      <div className="border-b border-gray-100 dark:border-gray-700 px-2 py-1.5 flex items-center gap-0.5 bg-gray-50/50 dark:bg-gray-800/50">
+      <div
+        id={toolbarId}
+        className="border-b border-gray-100 dark:border-gray-700 px-2 py-1.5 flex items-center gap-0.5 bg-gray-50/50 dark:bg-gray-800/50"
+        role="toolbar"
+        aria-label={`${ariaLabel} formatting controls`}
+      >
         <ToolbarButton
           isActive={editor.isActive('bold')}
           onClick={() => editor.chain().focus().toggleBold().run()}
@@ -100,7 +121,11 @@ export default function RichTextEditor({
           <Strikethrough size={14} />
         </ToolbarButton>
 
-        <div className="w-px h-5 bg-gray-200 dark:bg-gray-700 mx-1" />
+        <div
+          className="w-px h-5 bg-gray-200 dark:bg-gray-700 mx-1"
+          role="separator"
+          aria-orientation="vertical"
+        />
 
         <ToolbarButton
           isActive={editor.isActive('bulletList')}
@@ -117,7 +142,11 @@ export default function RichTextEditor({
           <ListOrdered size={14} />
         </ToolbarButton>
 
-        <div className="w-px h-5 bg-gray-200 dark:bg-gray-700 mx-1" />
+        <div
+          className="w-px h-5 bg-gray-200 dark:bg-gray-700 mx-1"
+          role="separator"
+          aria-orientation="vertical"
+        />
 
         <ToolbarButton
           isActive={editor.isActive('code')}
diff --git a/src/app/hooks/__tests__/useAudioEnhancement.test.tsx b/src/app/hooks/__tests__/useAudioEnhancement.test.tsx
new file mode 100644
index 00000000..daf8c55f
--- /dev/null
+++ b/src/app/hooks/__tests__/useAudioEnhancement.test.tsx
@@ -0,0 +1,201 @@
+import { act, renderHook } from '@testing-library/react';
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import type { RefObject } from 'react';
+import { useAudioEnhancement } from '../useAudioEnhancement';
+
+type MockAudioParam = {
+  value: number;
+  setTargetAtTime: ReturnType<typeof vi.fn>;
+};
+
+type MockAudioNode = {
+  connect: ReturnType<typeof vi.fn>;
+};
+
+type MockBiquadFilter = MockAudioNode & {
+  type: BiquadFilterType;
+  frequency: MockAudioParam;
+  Q: MockAudioParam;
+  gain: MockAudioParam;
+};
+
+type MockCompressor = MockAudioNode & {
+  threshold: MockAudioParam;
+  knee: MockAudioParam;
+  ratio: MockAudioParam;
+  attack: MockAudioParam;
+  release: MockAudioParam;
+};
+
+type MockGain = MockAudioNode & {
+  gain: MockAudioParam;
+};
+
+const createAudioParam = (initialValue = 0): MockAudioParam => ({
+  value: initialValue,
+  setTargetAtTime: vi.fn(function setTargetAtTime(this: MockAudioParam, value: number) {
+    this.value = value;
+  }),
+});
+
+const createNode = (): MockAudioNode => ({
+  connect: vi.fn(),
+});
+
+const createBiquadFilter = (): MockBiquadFilter => ({
+  ...createNode(),
+  type: 'peaking',
+  frequency: createAudioParam(),
+  Q: createAudioParam(),
+  gain: createAudioParam(),
+});
+
+const createCompressor = (): MockCompressor => ({
+  ...createNode(),
+  threshold: createAudioParam(),
+  knee: createAudioParam(),
+  ratio: createAudioParam(),
+  attack: createAudioParam(),
+  release: createAudioParam(),
+});
+
+const createGain = (): MockGain => ({
+  ...createNode(),
+  gain: createAudioParam(1),
+});
+
+describe('useAudioEnhancement', () => {
+  const originalAudioContext = window.AudioContext;
+  const originalWebkitAudioContext = window.webkitAudioContext;
+
+  let createdFilters: MockBiquadFilter[];
+  let createdCompressors: MockCompressor[];
+  let createdGains: MockGain[];
+  let resume: ReturnType<typeof vi.fn>;
+  let close: ReturnType<typeof vi.fn>;
+
+  beforeEach(() => {
+    createdFilters = [];
+    createdCompressors = [];
+    createdGains = [];
+    resume = vi.fn(() => Promise.resolve());
+    close = vi.fn(() => Promise.resolve());
+
+    class MockAudioContext {
+      currentTime = 4;
+      destination = createNode();
+      resume = resume;
+      close = close;
+
+      createMediaElementSource() {
+        return createNode();
+      }
+
+      createBiquadFilter() {
+        const filter = createBiquadFilter();
+        createdFilters.push(filter);
+        return filter;
+      }
+
+      createDynamicsCompressor() {
+        const compressor = createCompressor();
+        createdCompressors.push(compressor);
+        return compressor;
+      }
+
+      createGain() {
+        const gain = createGain();
+        createdGains.push(gain);
+        return gain;
+      }
+    }
+
+    Object.defineProperty(window, 'AudioContext', {
+      configurable: true,
+      writable: true,
+      value: MockAudioContext,
+    });
+    Object.defineProperty(window, 'webkitAudioContext', {
+      configurable: true,
+      writable: true,
+      value: undefined,
+    });
+  });
+
+  afterEach(() => {
+    Object.defineProperty(window, 'AudioContext', {
+      configurable: true,
+      writable: true,
+      value: originalAudioContext,
+    });
+    Object.defineProperty(window, 'webkitAudioContext', {
+      configurable: true,
+      writable: true,
+      value: originalWebkitAudioContext,
+    });
+  });
+
+  it('builds a speech-focused enhancement graph when enabled', () => {
+    const video = document.createElement('video');
+    const videoRef = { current: video } as RefObject<HTMLVideoElement>;
+    const { result } = renderHook(() => useAudioEnhancement(videoRef));
+
+    act(() => result.current.toggle());
+
+    expect(result.current.enabled).toBe(true);
+    expect(resume).toHaveBeenCalledTimes(1);
+    expect(createdFilters.map((filter) => filter.type)).toEqual([
+      'highpass',
+      'lowpass',
+      'lowshelf',
+      'peaking',
+    ]);
+    expect(createdCompressors).toHaveLength(1);
+    expect(createdGains).toHaveLength(1);
+
+    expect(createdFilters[0].frequency.value).toBe(68);
+    expect(createdFilters[1].frequency.value).toBe(16280);
+    expect(createdFilters[2].gain.value).toBe(6);
+    expect(createdFilters[3].gain.value).toBe(6);
+    expect(createdCompressors[0].threshold.value).toBe(-27.6);
+    expect(createdGains[0].gain.value).toBe(1.018);
+  });
+
+  it('clamps enhancement controls before applying them', () => {
+    const video = document.createElement('video');
+    const videoRef = { current: video } as RefObject<HTMLVideoElement>;
+    const { result } = renderHook(() => useAudioEnhancement(videoRef));
+
+    act(() => result.current.toggle());
+    act(() => {
+      result.current.setBassBoost(50);
+      result.current.setVoiceClarity(-4);
+      result.current.setNoiseReduction(2);
+    });
+
+    expect(result.current.bassBoost).toBe(20);
+    expect(result.current.voiceClarity).toBe(0);
+    expect(result.current.noiseReduction).toBe(1);
+    expect(createdFilters[0].frequency.value).toBe(180);
+    expect(createdFilters[1].frequency.value).toBe(7600);
+    expect(createdFilters[2].gain.value).toBe(20);
+    expect(createdFilters[3].gain.value).toBe(0);
+  });
+
+  it('does not expose enhancement controls without Web Audio support', () => {
+    Object.defineProperty(window, 'AudioContext', {
+      configurable: true,
+      writable: true,
+      value: undefined,
+    });
+
+    const videoRef = { current: document.createElement('video') } as RefObject<HTMLVideoElement>;
+    const { result } = renderHook(() => useAudioEnhancement(videoRef));
+
+    act(() => result.current.toggle());
+
+    expect(result.current.isSupported).toBe(false);
+    expect(result.current.enabled).toBe(false);
+    expect(resume).not.toHaveBeenCalled();
+  });
+});
diff --git a/src/app/hooks/useAudioEnhancement.ts b/src/app/hooks/useAudioEnhancement.ts
index 84d58297..bdfa1388 100644
--- a/src/app/hooks/useAudioEnhancement.ts
+++ b/src/app/hooks/useAudioEnhancement.ts
@@ -3,11 +3,17 @@
 import { useState, useEffect, useCallback, useRef } from 'react';
 import type { RefObject } from 'react';
 
+declare global {
+  interface Window {
+    webkitAudioContext?: typeof AudioContext;
+  }
+}
+
 export interface AudioEnhancementState {
   enabled: boolean;
-  bassBoost: number;   // 0–20 dB
-  voiceClarity: number; // 0–20 dB
-  noiseReduction: number; // 0–1 (gain reduction)
+  bassBoost: number; // 0-20 dB
+  voiceClarity: number; // 0-20 dB
+  noiseReduction: number; // 0-1 speech-focused filtering amount
 }
 
 export interface UseAudioEnhancementReturn extends AudioEnhancementState {
@@ -25,77 +31,136 @@ const DEFAULT_STATE: AudioEnhancementState = {
   noiseReduction: 0.3,
 };
 
+const clamp = (value: number, min: number, max: number) => Math.min(max, Math.max(min, value));
+
+const getAudioContextConstructor = () => {
+  if (typeof window === 'undefined') return undefined;
+  return window.AudioContext ?? window.webkitAudioContext;
+};
+
+const setAudioParam = (param: AudioParam, value: number, context: AudioContext) => {
+  if (typeof param.setTargetAtTime === 'function') {
+    param.setTargetAtTime(value, context.currentTime, 0.015);
+    return;
+  }
+
+  param.value = value;
+};
+
 export function useAudioEnhancement(
   videoRef: RefObject<HTMLVideoElement>,
 ): UseAudioEnhancementReturn {
-  const isSupported = typeof window !== 'undefined' && 'AudioContext' in window;
+  const isSupported = !!getAudioContextConstructor();
 
   const [state, setState] = useState<AudioEnhancementState>(DEFAULT_STATE);
 
   const audioCtxRef = useRef<AudioContext | null>(null);
   const sourceRef = useRef<MediaElementAudioSourceNode | null>(null);
+  const highPassFilterRef = useRef<BiquadFilterNode | null>(null);
+  const lowPassFilterRef = useRef<BiquadFilterNode | null>(null);
   const bassFilterRef = useRef<BiquadFilterNode | null>(null);
-  const midFilterRef = useRef<BiquadFilterNode | null>(null);
-  const gainRef = useRef<GainNode | null>(null);
+  const voiceFilterRef = useRef<BiquadFilterNode | null>(null);
+  const compressorRef = useRef<DynamicsCompressorNode | null>(null);
+  const outputGainRef = useRef<GainNode | null>(null);
   const connectedRef = useRef(false);
 
   // Build the audio graph once the video element is available.
   const initGraph = useCallback(() => {
     if (!isSupported || !videoRef.current || connectedRef.current) return;
 
-    const ctx = new AudioContext();
+    const AudioContextConstructor = getAudioContextConstructor();
+    if (!AudioContextConstructor) return;
+
+    const ctx = new AudioContextConstructor();
     audioCtxRef.current = ctx;
 
     const source = ctx.createMediaElementSource(videoRef.current);
     sourceRef.current = source;
 
-    // Bass boost — low-shelf filter around 100 Hz
+    const highPass = ctx.createBiquadFilter();
+    highPass.type = 'highpass';
+    highPass.frequency.value = 20;
+    highPass.Q.value = 0.7;
+    highPassFilterRef.current = highPass;
+
+    const lowPass = ctx.createBiquadFilter();
+    lowPass.type = 'lowpass';
+    lowPass.frequency.value = 20000;
+    lowPass.Q.value = 0.7;
+    lowPassFilterRef.current = lowPass;
+
+    // Bass boost: low-shelf filter around 100 Hz.
     const bass = ctx.createBiquadFilter();
     bass.type = 'lowshelf';
     bass.frequency.value = 100;
-    bass.gain.value = 0; // off by default
+    bass.gain.value = 0;
     bassFilterRef.current = bass;
 
-    // Voice clarity — peaking filter around 3 kHz
-    const mid = ctx.createBiquadFilter();
-    mid.type = 'peaking';
-    mid.frequency.value = 3000;
-    mid.Q.value = 1;
-    mid.gain.value = 0; // off by default
-    midFilterRef.current = mid;
-
-    // Noise reduction approximated via a gain node (subtle attenuation)
-    const gain = ctx.createGain();
-    gain.gain.value = 1; // off by default
-    gainRef.current = gain;
-
-    source.connect(bass);
-    bass.connect(mid);
-    mid.connect(gain);
-    gain.connect(ctx.destination);
+    // Voice clarity: broad speech presence boost.
+    const voice = ctx.createBiquadFilter();
+    voice.type = 'peaking';
+    voice.frequency.value = 3000;
+    voice.Q.value = 1;
+    voice.gain.value = 0;
+    voiceFilterRef.current = voice;
+
+    const compressor = ctx.createDynamicsCompressor();
+    compressor.threshold.value = -24;
+    compressor.knee.value = 18;
+    compressor.ratio.value = 3;
+    compressor.attack.value = 0.006;
+    compressor.release.value = 0.18;
+    compressorRef.current = compressor;
+
+    const outputGain = ctx.createGain();
+    outputGain.gain.value = 1;
+    outputGainRef.current = outputGain;
+
+    source.connect(highPass);
+    highPass.connect(lowPass);
+    lowPass.connect(bass);
+    bass.connect(voice);
+    voice.connect(compressor);
+    compressor.connect(outputGain);
+    outputGain.connect(ctx.destination);
 
     connectedRef.current = true;
   }, [isSupported, videoRef]);
 
   // Apply current state values to the audio nodes.
   const applyState = useCallback((next: AudioEnhancementState) => {
-    if (!connectedRef.current) return;
+    const context = audioCtxRef.current;
+    if (!connectedRef.current || !context) return;
 
     const bassGain = next.enabled ? next.bassBoost : 0;
-    const midGain = next.enabled ? next.voiceClarity : 0;
-    // Noise reduction: reduce gain slightly when enabled
-    const gainValue = next.enabled ? 1 - next.noiseReduction * 0.2 : 1;
-
-    if (bassFilterRef.current) bassFilterRef.current.gain.value = bassGain;
-    if (midFilterRef.current) midFilterRef.current.gain.value = midGain;
-    if (gainRef.current) gainRef.current.gain.value = gainValue;
+    const voiceGain = next.enabled ? next.voiceClarity : 0;
+    const noiseReduction = next.enabled ? next.noiseReduction : 0;
+
+    // Trim low rumble and high-frequency hiss without globally lowering volume.
+    const highPassFrequency = 20 + noiseReduction * 160;
+    const lowPassFrequency = 20000 - noiseReduction * 12400;
+    const compressorThreshold = -24 - noiseReduction * 12;
+    const outputGain = next.enabled ? 1 + noiseReduction * 0.06 : 1;
+
+    if (highPassFilterRef.current) {
+      setAudioParam(highPassFilterRef.current.frequency, highPassFrequency, context);
+    }
+    if (lowPassFilterRef.current) {
+      setAudioParam(lowPassFilterRef.current.frequency, lowPassFrequency, context);
+    }
+    if (bassFilterRef.current) setAudioParam(bassFilterRef.current.gain, bassGain, context);
+    if (voiceFilterRef.current) setAudioParam(voiceFilterRef.current.gain, voiceGain, context);
+    if (compressorRef.current) {
+      setAudioParam(compressorRef.current.threshold, compressorThreshold, context);
+    }
+    if (outputGainRef.current) setAudioParam(outputGainRef.current.gain, outputGain, context);
   }, []);
 
   const toggle = useCallback(() => {
     if (!isSupported) return;
     initGraph();
-    // Resume AudioContext if suspended (browser autoplay policy)
-    audioCtxRef.current?.resume();
+    // Resume AudioContext if suspended by browser autoplay policy.
+    void audioCtxRef.current?.resume();
     setState((prev) => {
       const next = { ...prev, enabled: !prev.enabled };
       applyState(next);
@@ -106,7 +171,7 @@ export function useAudioEnhancement(
   const setBassBoost = useCallback(
     (value: number) => {
       setState((prev) => {
-        const next = { ...prev, bassBoost: value };
+        const next = { ...prev, bassBoost: clamp(value, 0, 20) };
         applyState(next);
         return next;
       });
@@ -117,7 +182,7 @@ export function useAudioEnhancement(
   const setVoiceClarity = useCallback(
     (value: number) => {
       setState((prev) => {
-        const next = { ...prev, voiceClarity: value };
+        const next = { ...prev, voiceClarity: clamp(value, 0, 20) };
         applyState(next);
         return next;
       });
@@ -128,7 +193,7 @@ export function useAudioEnhancement(
   const setNoiseReduction = useCallback(
     (value: number) => {
       setState((prev) => {
-        const next = { ...prev, noiseReduction: value };
+        const next = { ...prev, noiseReduction: clamp(value, 0, 1) };
         applyState(next);
         return next;
       });
@@ -139,7 +204,7 @@ export function useAudioEnhancement(
   // Cleanup on unmount.
   useEffect(() => {
     return () => {
-      audioCtxRef.current?.close();
+      void audioCtxRef.current?.close();
       connectedRef.current = false;
     };
   }, []);