Subcribe each instance of JitsiLocalTrack to audio output change event as there might be local tracks not inside a conference

modules/RTC/JitsiLocalTrack.js

         }
     };
 
+    // Subscribe each created local audio track to
+    // RTCEvents.AUDIO_OUTPUT_DEVICE_CHANGED event. This is different from
+    // handling this event for remote tracks (which are handled in RTC.js),
+    // because there might be local tracks not attached to a conference.
+    if (this.isAudioTrack() && RTCUtils.isDeviceChangeAvailable('output')) {
+        this._onAudioOutputDeviceChanged = this.setAudioOutput.bind(this);
+
+        RTCUtils.addListener(RTCEvents.AUDIO_OUTPUT_DEVICE_CHANGED,
+            this._onAudioOutputDeviceChanged);
+    }
 
     RTCUtils.addListener(RTCEvents.DEVICE_LIST_CHANGED,
         this._onDeviceListChanged);
     RTCUtils.removeListener(RTCEvents.DEVICE_LIST_CHANGED,
         this._onDeviceListChanged);
 
+    if (this._onAudioOutputDeviceChanged) {
+        RTCUtils.removeListener(RTCEvents.AUDIO_OUTPUT_DEVICE_CHANGED,
+            this._onAudioOutputDeviceChanged);
+    }
+
     return promise;
 };
 

modules/RTC/RTC.js

         }
     });
 
-    // switch audio output device on all local and remote audio tracks
-    RTCUtils.addListener(RTCEvents.AUDIO_OUTPUT_DEVICE_CHANGED,
-        function (deviceId) {
-            if (RTCUtils.isDeviceChangeAvailable('output')) {
-                if (self.localAudio) {
-                    self.localAudio.setAudioOutput(deviceId);
-                }
-
+    // Switch audio output device on all remote audio tracks. Local audio tracks
+    // handle this event by themselves.
+    if (RTCUtils.isDeviceChangeAvailable('output')) {
+        RTCUtils.addListener(RTCEvents.AUDIO_OUTPUT_DEVICE_CHANGED,
+            function (deviceId) {
                 for (var key in self.remoteTracks) {
                     if (self.remoteTracks.hasOwnProperty(key)
                         && self.remoteTracks[key].audio) {
                         self.remoteTracks[key].audio.setAudioOutput(deviceId);
                     }
                 }
-            }
-        });
+            });
+    }
 }
 
 /**