diff --git a/src/services/web-audio-api.service.js b/src/services/web-audio-api.service.js
index 2c72233..5a4b863 100644
--- a/src/services/web-audio-api.service.js
+++ b/src/services/web-audio-api.service.js
@@ -82,9 +82,9 @@ class WebAudioApiService {
     const audioSounds = Object.values(AUDIO_SOUND);
     const matchingAudioSound = audioSounds.find(({ ID }) => ID === id);
 
-    if (!matchingAudioSound) {
+    if (matchingAudioSound === undefined) {
       // Fallback to default if sound not found
-      return this.playSound(audioSounds[0].ID, volume);
+      return this.playSound(DEFAULT_SETTINGS.audioSound, volume);
     }
 
     try {
diff --git a/src/stores/app.js b/src/stores/app.js
index 19043f1..4897c99 100644
--- a/src/stores/app.js
+++ b/src/stores/app.js
@@ -1,5 +1,6 @@
 import LocalStorageService from '../services/local-storage.service.js';
 import {
+  BROWSER,
   CLIENT_ERROR_MESSAGE,
   STORAGE_KEY_NAMESPACE,
 } from '../utils/constants.js';
@@ -9,7 +10,7 @@ class AppStore {
   /** @type {string} */
   #visitedStorageKey = 'visited';
   /** @type {import("../index.d.js").UserAgent} */
-  #userAgent = 'unknown';
+  #userAgent = BROWSER.UNKNOWN;
   /** @type {boolean} */
   #hasUserVisited = true;
 
@@ -22,22 +23,7 @@ class AppStore {
     this.#hasUserVisited =
       hasUserVisitedValue !== null ? Boolean(hasUserVisitedValue) : false;
 
-    const userAgent = detectUserAgent();
-    if (
-      [
-        'chrome',
-        'chromium',
-        'edge',
-        'firefox',
-        'opera',
-        'safari',
-        'seamonkey',
-      ].includes(userAgent)
-    ) {
-      this.#userAgent = userAgent;
-    } else {
-      this.#userAgent = 'unknown';
-    }
+    this.#userAgent = detectUserAgent();
   }
 
   get visitedStorageKey() {
diff --git a/src/utils/constants.js b/src/utils/constants.js
index b64cb35..9b018eb 100644
--- a/src/utils/constants.js
+++ b/src/utils/constants.js
@@ -28,6 +28,18 @@ const AUDIO_VOLUME = Object.freeze({
   ONE_HUNDRED_PERCENT: 100,
 });
 
+/** @type {Readonly<Record<string, import("../index.d.js").UserAgent>>} */
+const BROWSER = Object.freeze({
+  CHROME: 'chrome',
+  CHROMIUM: 'chromium',
+  EDGE: 'edge',
+  FIREFOX: 'firefox',
+  OPERA: 'opera',
+  SAFARI: 'safari',
+  SEAMONKEY: 'seamonkey',
+  UNKNOWN: 'unknown',
+});
+
 const CLIENT_ERROR_MESSAGE = Object.freeze({
   STORAGE_INVALID: 'Storage invalid.',
   STORAGE_NAMESPACE_INVALID: 'Storage namespace invalid.',
@@ -191,6 +203,7 @@ export {
   APP_EVENT,
   AUDIO_SOUND,
   AUDIO_VOLUME,
+  BROWSER,
   CLIENT_ERROR_MESSAGE,
   EXERCISES_BY_CATEGORY_MAP,
   EXERCISE_CATEGORY,
diff --git a/src/utils/detectUserAgent.js b/src/utils/detectUserAgent.js
index 09fe20f..b8fe460 100644
--- a/src/utils/detectUserAgent.js
+++ b/src/utils/detectUserAgent.js
@@ -1,34 +1,39 @@
+import { BROWSER } from './constants.js';
+
 /** @returns {import("../index.d.js").UserAgent} */
 function detectUserAgent() {
   const userAgent = window.navigator.userAgent;
   switch (true) {
     case userAgent.includes('Firefox/') && !userAgent.includes('Seamonkey/'):
-      return 'firefox';
+      return BROWSER.FIREFOX;
 
     case userAgent.includes('Seamonkey/'):
-      return 'seamonkey';
+      return BROWSER.SEAMONKEY;
 
     case userAgent.includes('Chrome/') &&
       !userAgent.includes('Chromium/') &&
       !userAgent.includes('Edg/'):
-      return 'chrome';
+      return BROWSER.CHROME;
 
     case userAgent.includes('Chromium/'):
-      return 'chromium';
+      return BROWSER.CHROMIUM;
+
+    case userAgent.includes('Edg/'):
+      return BROWSER.EDGE;
 
     case userAgent.includes('Safari/') &&
       !userAgent.includes('Chrome/') &&
       !userAgent.includes('Chromium/'):
-      return 'safari';
+      return BROWSER.SAFARI;
 
     case userAgent.includes('OPR/'):
-      return 'opera';
+      return BROWSER.OPERA;
 
     case userAgent.includes('Opera/'):
-      return 'opera';
+      return BROWSER.OPERA;
 
     default:
-      return 'unknown';
+      return BROWSER.UNKNOWN;
   }
 }