Do not subscribe each JitsiTrack to RTCEvents.AUDIO_OUTPUT_DEVICE_CHANGED, instead subscribe once in RTC

modules/RTC/JitsiLocalTrack.js

     this.resolution = resolution;
     this.deviceId = deviceId;
     this.startMuted = false;
+    this.disposed = false;
     //FIXME: This dependacy is not necessary.
     this.conference = null;
     this.initialMSID = this.getMSID();
         this.detach();
     }
 
-    JitsiTrack.prototype.dispose.call(this);
+    this.disposed = true;
 
     RTCUtils.removeListener(RTCEvents.DEVICE_LIST_CHANGED,
         this._onDeviceListChanged);

modules/RTC/JitsiRemoteTrack.js

     this.eventEmitter.emit(JitsiTrackEvents.TRACK_VIDEOTYPE_CHANGED, type);
 };
 
+delete JitsiRemoteTrack.prototype.dispose;
+
 module.exports = JitsiRemoteTrack;

modules/RTC/JitsiTrack.js

     this.type = trackMediaType;
     this.track = track;
     this.videoType = videoType;
-    this.disposed = false;
 
     if(stream) {
         if (RTCBrowserType.isFirefox()) {
         }
         addMediaStreamInactiveHandler(stream, streamInactiveHandler);
     }
-
-    this._onAudioOutputDeviceChanged = this.setAudioOutput.bind(this);
-
-    if (this.isAudioTrack()) {
-        RTCUtils.addListener(RTCEvents.AUDIO_OUTPUT_DEVICE_CHANGED,
-            this._onAudioOutputDeviceChanged);
-    }
 }
 
 /**
 
 /**
  * Dispose sending the media track. And removes it from the HTML.
+ * NOTE: Works for local tracks only.
  */
 JitsiTrack.prototype.dispose = function () {
-    RTCUtils.removeListener(RTCEvents.AUDIO_OUTPUT_DEVICE_CHANGED,
-        this._onAudioOutputDeviceChanged);
-
-    this.disposed = true;
 };
 
 /**

modules/RTC/RTC.js

             videoTrack._setVideoType(data.value);
         }
     });
+
+    // 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);
+                }
+
+                for (var key in self.remoteTracks) {
+                    if (self.remoteTracks.hasOwnProperty(key)
+                        && self.remoteTracks[key].audio) {
+                        self.remoteTracks[key].audio.setAudioOutput(deviceId);
+                    }
+                }
+            }
+        });
 }
 
 /**