diff --git a/src/@types/global.d.ts b/src/@types/global.d.ts
index cdced6df59..102643dd6a 100644
--- a/src/@types/global.d.ts
+++ b/src/@types/global.d.ts
@@ -27,6 +27,7 @@ import {IntegrationManagers} from "../integrations/IntegrationManagers";
 import {ModalManager} from "../Modal";
 import SettingsStore from "../settings/SettingsStore";
 import {ActiveRoomObserver} from "../ActiveRoomObserver";
+import {Notifier} from "../Notifier";
 
 declare global {
     interface Window {
@@ -47,6 +48,7 @@ declare global {
         mxIntegrationManagers: typeof IntegrationManagers;
         singletonModalManager: ModalManager;
         mxSettingsStore: SettingsStore;
+        mxNotifier: typeof Notifier;
     }
 
     // workaround for https://github.com/microsoft/TypeScript/issues/30933
@@ -79,4 +81,8 @@ declare global {
     interface PromiseConstructor {
         allSettled<T>(promises: Promise<T>[]): Promise<Array<ISettledFulfilled<T> | ISettledRejected>>;
     }
+
+    interface HTMLAudioElement {
+        type?: string;
+    }
 }
diff --git a/src/BasePlatform.ts b/src/BasePlatform.ts
index acf72a986c..1d28aa7f9a 100644
--- a/src/BasePlatform.ts
+++ b/src/BasePlatform.ts
@@ -155,6 +155,8 @@ export default abstract class BasePlatform {
 
     loudNotification(ev: Event, room: Object) {
     }
+    clearNotification(notif: Notification) {
+    }
 
     /**
      * Returns a promise that resolves to a string representing the current version of the application.
diff --git a/src/Notifier.js b/src/Notifier.ts
similarity index 91%
rename from src/Notifier.js
rename to src/Notifier.ts
index 2ed302267e..473de6c161 100644
--- a/src/Notifier.js
+++ b/src/Notifier.ts
@@ -17,6 +17,9 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+import { MatrixEvent } from "matrix-js-sdk/src/models/event";
+import { Room } from "matrix-js-sdk/src/models/room";
+
 import { MatrixClientPeg } from './MatrixClientPeg';
 import SdkConfig from './SdkConfig';
 import PlatformPeg from './PlatformPeg';
@@ -28,9 +31,7 @@ import * as sdk from './index';
 import { _t } from './languageHandler';
 import Modal from './Modal';
 import SettingsStore from "./settings/SettingsStore";
-import {
-    hideToast as hideNotificationsToast,
-} from "./toasts/DesktopNotificationsToast";
+import { hideToast as hideNotificationsToast } from "./toasts/DesktopNotificationsToast";
 import {SettingLevel} from "./settings/SettingLevel";
 
 /*
@@ -55,7 +56,7 @@ const typehandlers = {
     },
 };
 
-const Notifier = {
+export const Notifier = {
     notifsByRoom: {},
 
     // A list of event IDs that we've received but need to wait until
@@ -63,14 +64,14 @@ const Notifier = {
     // or not
     pendingEncryptedEventIds: [],
 
-    notificationMessageForEvent: function(ev) {
+    notificationMessageForEvent: function(ev: MatrixEvent) {
         if (typehandlers.hasOwnProperty(ev.getContent().msgtype)) {
             return typehandlers[ev.getContent().msgtype](ev);
         }
         return TextForEvent.textForEvent(ev);
     },
 
-    _displayPopupNotification: function(ev, room) {
+    _displayPopupNotification: function(ev: MatrixEvent, room: Room) {
         const plaf = PlatformPeg.get();
         if (!plaf) {
             return;
@@ -125,7 +126,7 @@ const Notifier = {
         }
     },
 
-    getSoundForRoom: function(roomId) {
+    getSoundForRoom: function(roomId: string) {
         // We do no caching here because the SDK caches setting
         // and the browser will cache the sound.
         const content = SettingsStore.getValue("notificationSound", roomId);
@@ -153,12 +154,13 @@ const Notifier = {
         };
     },
 
-    _playAudioNotification: async function(ev, room) {
+    _playAudioNotification: async function(ev: MatrixEvent, room: Room) {
         const sound = this.getSoundForRoom(room.roomId);
         console.log(`Got sound ${sound && sound.name || "default"} for ${room.roomId}`);
 
         try {
-            const selector = document.querySelector(sound ? `audio[src='${sound.url}']` : "#messageAudio");
+            const selector =
+                document.querySelector<HTMLAudioElement>(sound ? `audio[src='${sound.url}']` : "#messageAudio");
             let audioElement = selector;
             if (!selector) {
                 if (!sound) {
@@ -207,7 +209,7 @@ const Notifier = {
         return plaf && plaf.supportsNotifications();
     },
 
-    setEnabled: function(enable, callback) {
+    setEnabled: function(enable: boolean, callback?: () => void) {
         const plaf = PlatformPeg.get();
         if (!plaf) return;
 
@@ -277,10 +279,11 @@ const Notifier = {
     },
 
     isAudioEnabled: function() {
-        return this.isEnabled() && SettingsStore.getValue("audioNotificationsEnabled");
+        // We don't route Audio via the HTML Notifications API so it is possible regardless of other things
+        return SettingsStore.getValue("audioNotificationsEnabled");
     },
 
-    setToolbarHidden: function(hidden, persistent = true) {
+    setToolbarHidden: function(hidden: boolean, persistent = true) {
         this.toolbarHidden = hidden;
 
         Analytics.trackEvent('Notifier', 'Set Toolbar Hidden', hidden);
@@ -289,7 +292,7 @@ const Notifier = {
 
         // update the info to localStorage for persistent settings
         if (persistent && global.localStorage) {
-            global.localStorage.setItem("notifications_hidden", hidden);
+            global.localStorage.setItem("notifications_hidden", String(hidden));
         }
     },
 
@@ -312,7 +315,7 @@ const Notifier = {
         return this.toolbarHidden;
     },
 
-    onSyncStateChange: function(state) {
+    onSyncStateChange: function(state: string) {
         if (state === "SYNCING") {
             this.isSyncing = true;
         } else if (state === "STOPPED" || state === "ERROR") {
@@ -320,7 +323,7 @@ const Notifier = {
         }
     },
 
-    onEvent: function(ev) {
+    onEvent: function(ev: MatrixEvent) {
         if (!this.isSyncing) return; // don't alert for any messages initially
         if (ev.sender && ev.sender.userId === MatrixClientPeg.get().credentials.userId) return;
 
@@ -338,7 +341,7 @@ const Notifier = {
         this._evaluateEvent(ev);
     },
 
-    onEventDecrypted: function(ev) {
+    onEventDecrypted: function(ev: MatrixEvent) {
         // 'decrypted' means the decryption process has finished: it may have failed,
         // in which case it might decrypt soon if the keys arrive
         if (ev.isDecryptionFailure()) return;
@@ -350,7 +353,7 @@ const Notifier = {
         this._evaluateEvent(ev);
     },
 
-    onRoomReceipt: function(ev, room) {
+    onRoomReceipt: function(ev: MatrixEvent, room: Room) {
         if (room.getUnreadNotificationCount() === 0) {
             // ideally we would clear each notification when it was read,
             // but we have no way, given a read receipt, to know whether
@@ -383,8 +386,8 @@ const Notifier = {
     },
 };
 
-if (!global.mxNotifier) {
-    global.mxNotifier = Notifier;
+if (!window.mxNotifier) {
+    window.mxNotifier = Notifier;
 }
 
-export default global.mxNotifier;
+export default window.mxNotifier;
diff --git a/src/settings/Settings.ts b/src/settings/Settings.ts
index 49d060a6b2..714d80f983 100644
--- a/src/settings/Settings.ts
+++ b/src/settings/Settings.ts
@@ -19,7 +19,6 @@ import { MatrixClient } from 'matrix-js-sdk/src/client';
 
 import { _td } from '../languageHandler';
 import {
-    AudioNotificationsEnabledController,
     NotificationBodyEnabledController,
     NotificationsEnabledController,
 } from "./controllers/NotificationControllers";
@@ -460,7 +459,6 @@ export const SETTINGS: {[setting: string]: ISetting} = {
     "audioNotificationsEnabled": {
         supportedLevels: LEVELS_DEVICE_ONLY_SETTINGS,
         default: true,
-        controller: new AudioNotificationsEnabledController(),
     },
     "enableWidgetScreenshots": {
         supportedLevels: LEVELS_ACCOUNT_SETTINGS,
diff --git a/src/settings/controllers/NotificationControllers.ts b/src/settings/controllers/NotificationControllers.ts
index fc50af6096..bf5971d02e 100644
--- a/src/settings/controllers/NotificationControllers.ts
+++ b/src/settings/controllers/NotificationControllers.ts
@@ -79,12 +79,3 @@ export class NotificationBodyEnabledController extends SettingController {
         return calculatedValue;
     }
 }
-
-export class AudioNotificationsEnabledController extends SettingController {
-    public getValueOverride(level: SettingLevel, roomId: string, calculatedValue: any): any {
-        if (!getNotifier().isPossible()) return false;
-
-        // Note: Audio notifications are *not* enabled by default.
-        return calculatedValue;
-    }
-}