text: /*!
   *  howler.js v2.1.2
   *  howlerjs.com
   *
   *  (c) 2013-2019, James Simpson of GoldFire Studios
   *  goldfirestudios.com
   *
   *  MIT License
   */
  
  (function() {
  
    'use strict';
  
    /** Global Methods **/
    /***************************************************************************/
  
    /**
     * Create the global controller. All contained methods and properties apply
     * to all sounds that are currently playing or will be in the future.
     */
    var HowlerGlobal = function() {
      this.init();
    };
    HowlerGlobal.prototype = {
      /**
       * Initialize the global Howler object.
       * @return {Howler}
       */
      init: function() {
        var self = this || Howler;
  
        // Create a global ID counter.
        self._counter = 1000;
  
        // Pool of unlocked HTML5 Audio objects.
        self._html5AudioPool = [];
        self.html5PoolSize = 10;
  
        // Internal properties.
        self._codecs = {};
        self._howls = [];
        self._muted = false;
        self._volume = 1;
        self._canPlayEvent = 'canplaythrough';
        self._navigator = (typeof window !== 'undefined' && window.navigator) ? window.navigator : null;
  
        // Public properties.
        self.masterGain = null;
        self.noAudio = false;
        self.usingWebAudio = true;
        self.autoSuspend = true;
        self.ctx = null;
  
        // Set to false to disable the auto audio unlocker.
        self.autoUnlock = true;
  
        // Setup the various state values for global tracking.
        self._setup();
  
        return self;
      },
      
     
      /**
       * Get/set the global volume for all sounds.
       * @param  {Float} vol Volume from 0.0 to 1.0.
       * @return {Howler/Float}     Returns self or current volume.
       */
      volume: function(vol) {
        var self = this || Howler;
        vol = parseFloat(vol);
  
        // If we don't have an AudioContext created yet, run the setup.
        if (!self.ctx) {
          setupAudioContext();
        }
  
        if (typeof vol !== 'undefined' && vol >= 0 && vol <= 1) {
          self._volume = vol;
  
          // Don't update any of the nodes if we are muted.
          if (self._muted) {
            return self;
          }
  
          // When using Web Audio, we just need to adjust the master gain.
          if (self.usingWebAudio) {
            self.masterGain.gain.setValueAtTime(vol, Howler.ctx.currentTime);
          }
  
          // Loop through and change volume for all HTML5 audio nodes.
          for (var i=0; i<self._howls.length; i++) {
            if (!self._howls[i]._webAudio) {
              // Get all of the sounds in this Howl group.
              var ids = self._howls[i]._getSoundIds();
  
              // Loop through all sounds and change the volumes.
              for (var j=0; j<ids.length; j++) {
                var sound = self._howls[i]._soundById(ids[j]);
  
                if (sound && sound._node) {
                  sound._node.volume = sound._volume * vol;
                }
              }
            }
          }
  
          return self;
        }
  
        return self._volume;
      },
  
      /**
       * Handle muting and unmuting globally.
       * @param  {Boolean} muted Is muted or not.
       */
      mute: function(muted) {
        var self = this || Howler;
  
        // If we don't have an AudioContext created yet, run the setup.
        if (!self.ctx) {
          setupAudioContext();
        }
  
        self._muted = muted;
  
        // With Web Audio, we just need to mute the master gain.
        if (self.usingWebAudio) {
          self.masterGain.gain.setValueAtTime(muted ? 0 : self._volume, Howler.ctx.currentTime);
        }
  
        // Loop through and mute all HTML5 Audio nodes.
        for (var i=0; i<self._howls.length; i++) {
          if (!self._howls[i]._webAudio) {
            // Get all of the sounds in this Howl group.
            var ids = self._howls[i]._getSoundIds();
  
            // Loop through all sounds and mark the audio node as muted.
            for (var j=0; j<ids.length; j++) {
              var sound = self._howls[i]._soundById(ids[j]);
  
              if (sound && sound._node) {
                sound._node.muted = (muted) ? true : sound._muted;
              }
            }
          }
        }
  
        return self;
      },
  
      /**
       * Unload and destroy all currently loaded Howl objects.
       * @return {Howler}
       */
      unload: function() {
        var self = this || Howler;
  
        for (var i=self._howls.length-1; i>=0; i--) {
          self._howls[i].unload();
        }
  
        // Create a new AudioContext to make sure it is fully reset.
        if (self.usingWebAudio && self.ctx && typeof self.ctx.close !== 'undefined') {
          self.ctx.close();
          self.ctx = null;
          setupAudioContext();
        }
  
        return self;
      },
  
      /**
       * Check for codec support of specific extension.
       * @param  {String} ext Audio file extention.
       * @return {Boolean}
       */
      codecs: function(ext) {
        return (this || Howler)._codecs[ext.replace(/^x-/, '')];
      },
  
      /**
       * Setup various state values for global tracking.
       * @return {Howler}
       */
      _setup: function() {
        var self = this || Howler;
  
        // Keeps track of the suspend/resume state of the AudioContext.
        self.state = self.ctx ? self.ctx.state || 'suspended' : 'suspended';
  
        // Automatically begin the 30-second suspend process
        self._autoSuspend();
  
        // Check if audio is available.
        if (!self.usingWebAudio) {
          // No audio is available on this system if noAudio is set to true.
          if (typeof Audio !== 'undefined') {
            try {
              var test = new Audio();
  
              // Check if the canplaythrough event is available.
              if (typeof test.oncanplaythrough === 'undefined') {
                self._canPlayEvent = 'canplay';
              }
            } catch(e) {
              self.noAudio = true;
            }
          } else {
            self.noAudio = true;
          }
        }
  
        // Test to make sure audio isn't disabled in Internet Explorer.
        try {
          var test = new Audio();
          if (test.muted) {
            self.noAudio = true;
          }
        } catch (e) {}
  
        // Check for supported codecs.
        if (!self.noAudio) {
          self._setupCodecs();
        }
  
        return self;
      },
  
      /**
       * Check for browser support for various codecs and cache the results.
       * @return {Howler}
       */
      _setupCodecs: function() {
        var self = this || Howler;
        var audioTest = null;
  
        // Must wrap in a try/catch because IE11 in server mode throws an error.
        try {
          audioTest = (typeof Audio !== 'undefined') ? new Audio() : null;
        } catch (err) {
          return self;
        }
  
        if (!audioTest || typeof audioTest.canPlayType !== 'function') {
          return self;
        }
  
        var mpegTest = audioTest.canPlayType('audio/mpeg;').replace(/^no$/, '');
  
        // Opera version <33 has mixed MP3 support, so we need to check for and block it.
        var checkOpera = self._navigator && self._navigator.userAgent.match(/OPR\/([0-6].)/g);
        var isOldOpera = (checkOpera && parseInt(checkOpera[0].split('/')[1], 10) < 33);
  
        self._codecs = {
          mp3: !!(!isOldOpera && (mpegTest || audioTest.canPlayType('audio/mp3;').replace(/^no$/, ''))),
          mpeg: !!mpegTest,
          opus: !!audioTest.canPlayType('audio/ogg; codecs="opus"').replace(/^no$/, ''),
          ogg: !!audioTest.canPlayType('audio/ogg; codecs="vorbis"').replace(/^no$/, ''),
          oga: !!audioTest.canPlayType('audio/ogg; codecs="vorbis"').replace(/^no$/, ''),
          wav: !!audioTest.canPlayType('audio/wav; codecs="1"').replace(/^no$/, ''),
          aac: !!audioTest.canPlayType('audio/aac;').replace(/^no$/, ''),
          caf: !!audioTest.canPlayType('audio/x-caf;').replace(/^no$/, ''),
          m4a: !!(audioTest.canPlayType('audio/x-m4a;') || audioTest.canPlayType('audio/m4a;') || audioTest.canPlayType('audio/aac;')).replace(/^no$/, ''),
          mp4: !!(audioTest.canPlayType('audio/x-mp4;') || audioTest.canPlayType('audio/mp4;') || audioTest.canPlayType('audio/aac;')).replace(/^no$/, ''),
          weba: !!audioTest.canPlayType('audio/webm; codecs="vorbis"').replace(/^no$/, ''),
          webm: !!audioTest.canPlayType('audio/webm; codecs="vorbis"').replace(/^no$/, ''),
          dolby: !!audioTest.canPlayType('audio/mp4; codecs="ec-3"').replace(/^no$/, ''),
          flac: !!(audioTest.canPlayType('audio/x-flac;') || audioTest.canPlayType('audio/flac;')).replace(/^no$/, '')
        };
  
        return self;
      },
  
      /**
       * Some browsers/devices will only allow audio to be played after a user interaction.
       * Attempt to automatically unlock audio on the first user interaction.
       * Concept from: http://paulbakaus.com/tutorials/html5/web-audio-on-ios/
       * @return {Howler}
       */
      _unlockAudio: function() {
        var self = this || Howler;
  
        // Only run this if Web Audio is supported and it hasn't already been unlocked.
        if (self._audioUnlocked || !self.ctx) {
          return;
        }
  
        self._audioUnlocked = false;
        self.autoUnlock = false;
  
        // Some mobile devices/platforms have distortion issues when opening/closing tabs and/or web views.
        // Bugs in the browser (especially Mobile Safari) can cause the sampleRate to change from 44100 to 48000.
        // By calling Howler.unload(), we create a new AudioContext with the correct sampleRate.
        if (!self._mobileUnloaded && self.ctx.sampleRate !== 44100) {
          self._mobileUnloaded = true;
          self.unload();
        }
  
        // Scratch buffer for enabling iOS to dispose of web audio buffers correctly, as per:
        // http://stackoverflow.com/questions/24119684
        self._scratchBuffer = self.ctx.createBuffer(1, 1, 22050);
  
        // Call this method on touch start to create and play a buffer,
        // then check if the audio actually played to determine if
        // audio has now been unlocked on iOS, Android, etc.
        var unlock = function(e) {
          // Create a pool of unlocked HTML5 Audio objects that can
          // be used for playing sounds without user interaction. HTML5
          // Audio objects must be individually unlocked, as opposed
          // to the WebAudio API which only needs a single activation.
          // This must occur before WebAudio setup or the source.onended
          // event will not fire.
          for (var i=0; i<self.html5PoolSize; i++) {
            try {
              var audioNode = new Audio();
  
              // Mark this Audio object as unlocked to ensure it can get returned
              // to the unlocked pool when released.
              audioNode._unlocked = true;
  
              // Add the audio node to the pool.
              self._releaseHtml5Audio(audioNode);
            } catch (e) {
              self.noAudio = true;
            }
          }
  
          // Loop through any assigned audio nodes and unlock them.
          for (var i=0; i<self._howls.length; i++) {
            if (!self._howls[i]._webAudio) {
              // Get all of the sounds in this Howl group.
              var ids = self._howls[i]._getSoundIds();
  
              // Loop through all sounds and unlock the audio nodes.
              for (var j=0; j<ids.length; j++) {
                var sound = self._howls[i]._soundById(ids[j]);
  
                if (sound && sound._node && !sound._node._unlocked) {
                  sound._node._unlocked = true;
                  sound._node.load();
                }
              }
            }
          }
  
          // Fix Android can not play in suspend state.
          self._autoResume();
  
          // Create an empty buffer.
          var source = self.ctx.createBufferSource();
          source.buffer = self._scratchBuffer;
          source.connect(self.ctx.destination);
  
          // Play the empty buffer.
          if (typeof source.start === 'undefined') {
            source.noteOn(0);
          } else {
            source.start(0);
          }
  
          // Calling resume() on a stack initiated by user gesture is what actually unlocks the audio on Android Chrome >= 55.
          if (typeof self.ctx.resume === 'function') {
            self.ctx.resume();
          }
  
          // Setup a timeout to check that we are unlocked on the next event loop.
          source.onended = function() {
            source.disconnect(0);
  
            // Update the unlocked state and prevent this check from happening again.
            self._audioUnlocked = true;
  
            // Remove the touch start listener.
            document.removeEventListener('touchstart', unlock, true);
            document.removeEventListener('touchend', unlock, true);
            document.removeEventListener('click', unlock, true);
  
            // Let all sounds know that audio has been unlocked.
            for (var i=0; i<self._howls.length; i++) {
              self._howls[i]._emit('unlock');
            }
          };
        };
  
        // Setup a touch start listener to attempt an unlock in.
        document.addEventListener('touchstart', unlock, true);
        document.addEventListener('touchend', unlock, true);
        document.addEventListener('click', unlock, true);
  
        return self;
      },
  
      /**
       * Get an unlocked HTML5 Audio object from the pool. If none are left,
       * return a new Audio object and throw a warning.
       * @return {Audio} HTML5 Audio object.
       */
      _obtainHtml5Audio: function() {
        var self = this || Howler;
  
        // Return the next object from the pool if one exists.
        if (self._html5AudioPool.length) {
          return self._html5AudioPool.pop();
        }
  
        //.Check if the audio is locked and throw a warning.
        var testPlay = new Audio().play();
        if (testPlay && typeof Promise !== 'undefined' && (testPlay instanceof Promise || typeof testPlay.then === 'function')) {
          testPlay.catch(function() {
            console.warn('HTML5 Audio pool exhausted, returning potentially locked audio object.');
          });
        }
  
        return new Audio();
      },
  
      /**
       * Return an activated HTML5 Audio object to the pool.
       * @return {Howler}
       */
      _releaseHtml5Audio: function(audio) {
        var self = this || Howler;
  
        // Don't add audio to the pool if we don't know if it has been unlocked.
        if (audio._unlocked) {
          self._html5AudioPool.push(audio);
        }
  
        return self;
      },
  
      /**
       * Automatically suspend the Web Audio AudioContext after no sound has played for 30 seconds.
       * This saves processing/energy and fixes various browser-specific bugs with audio getting stuck.
       * @return {Howler}
       */
      _autoSuspend: function() {
        var self = this;
  
        if (!self.autoSuspend || !self.ctx || typeof self.ctx.suspend === 'undefined' || !Howler.usingWebAudio) {
          return;
        }
  
        // Check if any sounds are playing.
        for (var i=0; i<self._howls.length; i++) {
          if (self._howls[i]._webAudio) {
            for (var j=0; j<self._howls[i]._sounds.length; j++) {
              if (!self._howls[i]._sounds[j]._paused) {
                return self;
              }
            }
          }
        }
  
        if (self._suspendTimer) {
          clearTimeout(self._suspendTimer);
        }
  
        // If no sound has played after 30 seconds, suspend the context.
        self._suspendTimer = setTimeout(function() {
          if (!self.autoSuspend) {
            return;
          }
  
          self._suspendTimer = null;
          self.state = 'suspending';
          self.ctx.suspend().then(function() {
            self.state = 'suspended';
  
            if (self._resumeAfterSuspend) {
              delete self._resumeAfterSuspend;
              self._autoResume();
            }
          });
        }, 30000);
  
        return self;
      },
  
      /**
       * Automatically resume the Web Audio AudioContext when a new sound is played.
       * @return {Howler}
       */
      _autoResume: function() {
        var self = this;
  
        if (!self.ctx || typeof self.ctx.resume === 'undefined' || !Howler.usingWebAudio) {
          return;
        }
  
        if (self.state === 'running' && self._suspendTimer) {
          clearTimeout(self._suspendTimer);
          self._suspendTimer = null;
        } else if (self.state === 'suspended') {
          self.ctx.resume().then(function() {
            self.state = 'running';
  
            // Emit to all Howls that the audio has resumed.
            for (var i=0; i<self._howls.length; i++) {
              self._howls[i]._emit('resume');
            }
          });
  
          if (self._suspendTimer) {
            clearTimeout(self._suspendTimer);
            self._suspendTimer = null;
          }
        } else if (self.state === 'suspending') {
          self._resumeAfterSuspend = true;
        }
  
        return self;
      }
    };
  
    // Setup the global audio controller.
    var Howler = new HowlerGlobal();
  
    /** Group Methods **/
    /***************************************************************************/
  
    /**
     * Create an audio group controller.
     * @param {Object} o Passed in properties for this group.
     */
    var Howl = function(o) {
      var self = this;
  
      // Throw an error if no source is provided.
      if (!o.src || o.src.length === 0) {
        console.error('An array of source files must be passed with any new Howl.');
        return;
      }
  
      self.init(o);
    };
    Howl.prototype = {
      /**
       * Initialize a new Howl group object.
       * @param  {Object} o Passed in properties for this group.
       * @return {Howl}
       */
      init: function(o) {
        var self = this;
  
        // If we don't have an AudioContext created yet, run the setup.
        if (!Howler.ctx) {
          setupAudioContext();
        }
  
        // Setup user-defined default properties.
        self._autoplay = o.autoplay || false;
        self._format = (typeof o.format !== 'string') ? o.format : [o.format];
        self._html5 = o.html5 || false;
        self._muted = o.mute || false;
        self._loop = o.loop || false;
        self._pool = o.pool || 5;
        self._preload = (typeof o.preload === 'boolean') ? o.preload : true;
        self._rate = o.rate || 1;
        self._sprite = o.sprite || {};
        self._src = (typeof o.src !== 'string') ? o.src : [o.src];
        self._volume = o.volume !== undefined ? o.volume : 1;
        self._xhrWithCredentials = o.xhrWithCredentials || false;
  
        // Setup all other default properties.
        self._duration = 0;
        self._state = 'unloaded';
        self._sounds = [];
        self._endTimers = {};
        self._queue = [];
        self._playLock = false;
  
        // Setup event listeners.
        self._onend = o.onend ? [{fn: o.onend}] : [];
        self._onfade = o.onfade ? [{fn: o.onfade}] : [];
        self._onload = o.onload ? [{fn: o.onload}] : [];
        self._onloaderror = o.onloaderror ? [{fn: o.onloaderror}] : [];
        self._onplayerror = o.onplayerror ? [{fn: o.onplayerror}] : [];
        self._onpause = o.onpause ? [{fn: o.onpause}] : [];
        self._onplay = o.onplay ? [{fn: o.onplay}] : [];
        self._onstop = o.onstop ? [{fn: o.onstop}] : [];
        self._onmute = o.onmute ? [{fn: o.onmute}] : [];
        self._onvolume = o.onvolume ? [{fn: o.onvolume}] : [];
        self._onrate = o.onrate ? [{fn: o.onrate}] : [];
        self._onseek = o.onseek ? [{fn: o.onseek}] : [];
        self._onunlock = o.onunlock ? [{fn: o.onunlock}] : [];
        self._onresume = [];
  
        // Web Audio or HTML5 Audio?
        self._webAudio = Howler.usingWebAudio && !self._html5;
  
        // Automatically try to enable audio.
        if (typeof Howler.ctx !== 'undefined' && Howler.ctx && Howler.autoUnlock) {
          Howler._unlockAudio();
        }
  
        // Keep track of this Howl group in the global controller.
        Howler._howls.push(self);
  
        // If they selected autoplay, add a play event to the load queue.
        if (self._autoplay) {
          self._queue.push({
            event: 'play',
            action: function() {
              self.play();
            }
          });
        }
  
        // Load the source file unless otherwise specified.
        if (self._preload) {
          self.load();
        }
  
        return self;
      },
      
       
      changeSrc: function (newSrc) {
          var self = this;
          self.unload(true);
          self._src = newSrc;
          self.load();
      },
      
  
      /**
       * Load the audio file.
       * @return {Howler}
       */
      load: function() {
        var self = this;
        var url = null;
  
        // If no audio is available, quit immediately.
        if (Howler.noAudio) {
          self._emit('loaderror', null, 'No audio support.');
          return;
        }
  
        // Make sure our source is in an array.
        if (typeof self._src === 'string') {
          self._src = [self._src];
        }
  
        // Loop through the sources and pick the first one that is compatible.
        for (var i=0; i<self._src.length; i++) {
          var ext, str;
  
          if (self._format && self._format[i]) {
            // If an extension was specified, use that instead.
            ext = self._format[i];
          } else {
            // Make sure the source is a string.
            str = self._src[i];
            if (typeof str !== 'string') {
              self._emit('loaderror', null, 'Non-string found in selected audio sources - ignoring.');
              continue;
            }
  
            // Extract the file extension from the URL or base64 data URI.
            ext = /^data:audio\/([^;,]+);/i.exec(str);
            if (!ext) {
              ext = /\.([^.]+)$/.exec(str.split('?', 1)[0]);
            }
  
            if (ext) {
              ext = ext[1].toLowerCase();
            }
          }
  
          // Log a warning if no extension was found.
          if (!ext) {
            console.warn('No file extension was found. Consider using the "format" property or specify an extension.');
          }
  
          // Check if this extension is available.
          if (ext && Howler.codecs(ext)) {
            url = self._src[i];
            break;
          }
        }
  
        if (!url) {
          self._emit('loaderror', null, 'No codec support for selected audio sources.');
          return;
        }
  
        self._src = url;
        self._state = 'loading';
  
        // If the hosting page is HTTPS and the source isn't,
        // drop down to HTML5 Audio to avoid Mixed Content errors.
        if (window.location.protocol === 'https:' && url.slice(0, 5) === 'http:') {
          self._html5 = true;
          self._webAudio = false;
        }
  
        // Create a new sound object and add it to the pool.
        new Sound(self);
  
        // Load and decode the audio data for playback.
        if (self._webAudio) {
          loadBuffer(self);
        }
  
        return self;
      },
  
      /**
       * Play a sound or resume previous playback.
       * @param  {String/Number} sprite   Sprite name for sprite playback or sound id to continue previous.
       * @param  {Boolean} internal Internal Use: true prevents event firing.
       * @return {Number}          Sound ID.
       */
      play: function(sprite, internal) {
        var self = this;
        var id = null;
  
        // Determine if a sprite, sound id or nothing was passed
        if (typeof sprite === 'number') {
          id = sprite;
          sprite = null;
        } else if (typeof sprite === 'string' && self._state === 'loaded' && !self._sprite[sprite]) {
          // If the passed sprite doesn't exist, do nothing.
          return null;
        } else if (typeof sprite === 'undefined') {
          // Use the default sound sprite (plays the full audio length).
          sprite = '__default';
  
          // Check if there is a single paused sound that isn't ended. 
          // If there is, play that sound. If not, continue as usual.  
          if (!self._playLock) {
            var num = 0;
            for (var i=0; i<self._sounds.length; i++) {
              if (self._sounds[i]._paused && !self._sounds[i]._ended) {
                num++;
                id = self._sounds[i]._id;
              }
            }
  
            if (num === 1) {
              sprite = null;
            } else {
              id = null;
            }
          }
        }
  
        // Get the selected node, or get one from the pool.
        var sound = id ? self._soundById(id) : self._inactiveSound();
  
        // If the sound doesn't exist, do nothing.
        if (!sound) {
          return null;
        }
  
        // Select the sprite definition.
        if (id && !sprite) {
          sprite = sound._sprite || '__default';
        }
  
        // If the sound hasn't loaded, we must wait to get the audio's duration.
        // We also need to wait to make sure we don't run into race conditions with
        // the order of function calls.
        if (self._state !== 'loaded') {
          // Set the sprite value on this sound.
          sound._sprite = sprite;
  
          // Mark this sound as not ended in case another sound is played before this one loads.
          sound._ended = false;
  
          // Add the sound to the queue to be played on load.
          var soundId = sound._id;
          self._queue.push({
            event: 'play',
            action: function() {
              self.play(soundId);
            }
          });
  
          return soundId;
        }
  
        // Don't play the sound if an id was passed and it is already playing.
        if (id && !sound._paused) {
          // Trigger the play event, in order to keep iterating through queue.
          if (!internal) {
            self._loadQueue('play');
          }
  
          return sound._id;
        }
  
        // Make sure the AudioContext isn't suspended, and resume it if it is.
        if (self._webAudio) {
          Howler._autoResume();
        }
  
        // Determine how long to play for and where to start playing.
        var seek = Math.max(0, sound._seek > 0 ? sound._seek : self._sprite[sprite][0] / 1000);
        var duration = Math.max(0, ((self._sprite[sprite][0] + self._sprite[sprite][1]) / 1000) - seek);
        var timeout = (duration * 1000) / Math.abs(sound._rate);
        var start = self._sprite[sprite][0] / 1000;
        var stop = (self._sprite[sprite][0] + self._sprite[sprite][1]) / 1000;
        var loop = !!(sound._loop || self._sprite[sprite][2]);
        sound._sprite = sprite;
  
        // Mark the sound as ended instantly so that this async playback
        // doesn't get grabbed by another call to play while this one waits to start.
        sound._ended = false;
  
        // Update the parameters of the sound.
        var setParams = function() {
          sound._paused = false;
          sound._seek = seek;
          sound._start = start;
          sound._stop = stop;
          sound._loop = loop;
        };
  
        // End the sound instantly if seek is at the end.
        if (seek >= stop) {
          self._ended(sound);
          return;
        }
  
        // Begin the actual playback.
        var node = sound._node;
        if (self._webAudio) {
          // Fire this when the sound is ready to play to begin Web Audio playback.
          var playWebAudio = function() {
            self._playLock = false;
            setParams();
            self._refreshBuffer(sound);
  
            // Setup the playback params.
            var vol = (sound._muted || self._muted) ? 0 : sound._volume;
            node.gain.setValueAtTime(vol, Howler.ctx.currentTime);
            sound._playStart = Howler.ctx.currentTime;
  
            // Play the sound using the supported method.
            if (typeof node.bufferSource.start === 'undefined') {
              sound._loop ? node.bufferSource.noteGrainOn(0, seek, 86400) : node.bufferSource.noteGrainOn(0, seek, duration);
            } else {
              sound._loop ? node.bufferSource.start(0, seek, 86400) : node.bufferSource.start(0, seek, duration);
            }
  
            // Start a new timer if none is present.
            if (timeout !== Infinity) {
              self._endTimers[sound._id] = setTimeout(self._ended.bind(self, sound), timeout);
            }
  
            if (!internal) {
              setTimeout(function() {
                self._emit('play', sound._id);
                self._loadQueue();
              }, 0);
            }
          };
  
          if (Howler.state === 'running') {
            playWebAudio();
          } else {
            self._playLock = true;
  
            // Wait for the audio context to resume before playing.
            self.once('resume', playWebAudio);
  
            // Cancel the end timer.
            self._clearTimer(sound._id);
          }
        } else {
          // Fire this when the sound is ready to play to begin HTML5 Audio playback.
          var playHtml5 = function() {
            node.currentTime = seek;
            node.muted = sound._muted || self._muted || Howler._muted || node.muted;
            node.volume = sound._volume * Howler.volume();
            node.playbackRate = sound._rate;
  
            // Some browsers will throw an error if this is called without user interaction.
            try {
              var play = node.play();
  
              // Support older browsers that don't support promises, and thus don't have this issue.
              if (play && typeof Promise !== 'undefined' && (play instanceof Promise || typeof play.then === 'function')) {
                // Implements a lock to prevent DOMException: The play() request was interrupted by a call to pause().
                self._playLock = true;
  
                // Set param values immediately.
                setParams();
  
                // Releases the lock and executes queued actions.
                play
                  .then(function() {
                    self._playLock = false;
                    node._unlocked = true;
                    if (!internal) {
                      self._emit('play', sound._id);
                      self._loadQueue();
                    }
                  })
                  .catch(function() {
                    self._playLock = false;
                    self._emit('playerror', sound._id, 'Playback was unable to start. This is most commonly an issue ' +
                      'on mobile devices and Chrome where playback was not within a user interaction.');
  
                    // Reset the ended and paused values.
                    sound._ended = true;
                    sound._paused = true;
                  });
              } else if (!internal) {
                self._playLock = false;
                setParams();
                self._emit('play', sound._id);
                self._loadQueue();
              }
  
              // Setting rate before playing won't work in IE, so we set it again here.
              node.playbackRate = sound._rate;
  
              // If the node is still paused, then we can assume there was a playback issue.
              if (node.paused) {
                self._emit('playerror', sound._id, 'Playback was unable to start. This is most commonly an issue ' +
                  'on mobile devices and Chrome where playback was not within a user interaction.');
                return;
              }
  
              // Setup the end timer on sprites or listen for the ended event.
              if (sprite !== '__default' || sound._loop) {
                self._endTimers[sound._id] = setTimeout(self._ended.bind(self, sound), timeout);
              } else {
                self._endTimers[sound._id] = function() {
                  // Fire ended on this audio node.
                  self._ended(sound);
  
                  // Clear this listener.
                  node.removeEventListener('ended', self._endTimers[sound._id], false);
                };
                node.addEventListener('ended', self._endTimers[sound._id], false);
              }
            } catch (err) {
              self._emit('playerror', sound._id, err);
            }
          };
  
          // If this is streaming audio, make sure the src is set and load again.
          if (node.src === 'data:audio/wav;base64,UklGRigAAABXQVZFZm10IBIAAAABAAEARKwAAIhYAQACABAAAABkYXRhAgAAAAEA') {
            node.src = self._src;
            node.load();
          }
  
          // Play immediately if ready, or wait for the 'canplaythrough'e vent.
          var loadedNoReadyState = (window && window.ejecta) || (!node.readyState && Howler._navigator.isCocoonJS);
          if (node.readyState >= 3 || loadedNoReadyState) {
            playHtml5();
          } else {
            self._playLock = true;
  
            var listener = function() {
              // Begin playback.
              playHtml5();
  
              // Clear this listener.
              node.removeEventListener(Howler._canPlayEvent, listener, false);
            };
            node.addEventListener(Howler._canPlayEvent, listener, false);
  
            // Cancel the end timer.
            self._clearTimer(sound._id);
          }
        }
  
        return sound._id;
      },
  
      /**
       * Pause playback and save current position.
       * @param  {Number} id The sound ID (empty to pause all in group).
       * @return {Howl}
       */
      pause: function(id) {
        var self = this;
  
        // If the sound hasn't loaded or a play() promise is pending, add it to the load queue to pause when capable.
        if (self._state !== 'loaded' || self._playLock) {
          self._queue.push({
            event: 'pause',
            action: function() {
              self.pause(id);
            }
          });
  
          return self;
        }
  
        // If no id is passed, get all ID's to be paused.
        var ids = self._getSoundIds(id);
  
        for (var i=0; i<ids.length; i++) {
          // Clear the end timer.
          self._clearTimer(ids[i]);
  
          // Get the sound.
          var sound = self._soundById(ids[i]);
  
          if (sound && !sound._paused) {
            // Reset the seek position.
            sound._seek = self.seek(ids[i]);
            sound._rateSeek = 0;
            sound._paused = true;
  
            // Stop currently running fades.
            self._stopFade(ids[i]);
  
            if (sound._node) {
              if (self._webAudio) {
                // Make sure the sound has been created.
                if (!sound._node.bufferSource) {
                  continue;
                }
  
                if (typeof sound._node.bufferSource.stop === 'undefined') {
                  sound._node.bufferSource.noteOff(0);
                } else {
                  sound._node.bufferSource.stop(0);
                }
  
                // Clean up the buffer source.
                self._cleanBuffer(sound._node);
              } else if (!isNaN(sound._node.duration) || sound._node.duration === Infinity) {
                sound._node.pause();
              }
            }
          }
  
          // Fire the pause event, unless `true` is passed as the 2nd argument.
          if (!arguments[1]) {
            self._emit('pause', sound ? sound._id : null);
          }
        }
  
        return self;
      },
  
      /**
       * Stop playback and reset to start.
       * @param  {Number} id The sound ID (empty to stop all in group).
       * @param  {Boolean} internal Internal Use: true prevents event firing.
       * @return {Howl}
       */
      stop: function(id, internal) {
        var self = this;
  
        // If the sound hasn't loaded, add it to the load queue to stop when capable.
        if (self._state !== 'loaded' || self._playLock) {
          self._queue.push({
            event: 'stop',
            action: function() {
              self.stop(id);
            }
          });
  
          return self;
        }
  
        // If no id is passed, get all ID's to be stopped.
        var ids = self._getSoundIds(id);
  
        for (var i=0; i<ids.length; i++) {
          // Clear the end timer.
          self._clearTimer(ids[i]);
  
          // Get the sound.
          var sound = self._soundById(ids[i]);
  
          if (sound) {
            // Reset the seek position.
            sound._seek = sound._start || 0;
            sound._rateSeek = 0;
            sound._paused = true;
            sound._ended = true;
  
            // Stop currently running fades.
            self._stopFade(ids[i]);
  
            if (sound._node) {
              if (self._webAudio) {
                // Make sure the sound's AudioBufferSourceNode has been created.
                if (sound._node.bufferSource) {
                  if (typeof sound._node.bufferSource.stop === 'undefined') {
                    sound._node.bufferSource.noteOff(0);
                  } else {
                    sound._node.bufferSource.stop(0);
                  }
  
                  // Clean up the buffer source.
                  self._cleanBuffer(sound._node);
                }
              } else if (!isNaN(sound._node.duration) || sound._node.duration === Infinity) {
                sound._node.currentTime = sound._start || 0;
                sound._node.pause();
  
                // If this is a live stream, stop download once the audio is stopped.
                if (sound._node.duration === Infinity) {
                  self._clearSound(sound._node);
                }
              }
            }
  
            if (!internal) {
              self._emit('stop', sound._id);
            }
          }
        }
  
        return self;
      },
  
      /**
       * Mute/unmute a single sound or all sounds in this Howl group.
       * @param  {Boolean} muted Set to true to mute and false to unmute.
       * @param  {Number} id    The sound ID to update (omit to mute/unmute all).
       * @return {Howl}
       */
      mute: function(muted, id) {
        var self = this;
  
        // If the sound hasn't loaded, add it to the load queue to mute when capable.
        if (self._state !== 'loaded'|| self._playLock) {
          self._queue.push({
            event: 'mute',
            action: function() {
              self.mute(muted, id);
            }
          });
  
          return self;
        }
  
        // If applying mute/unmute to all sounds, update the group's value.
        if (typeof id === 'undefined') {
          if (typeof muted === 'boolean') {
            self._muted = muted;
          } else {
            return self._muted;
          }
        }
  
        // If no id is passed, get all ID's to be muted.
        var ids = self._getSoundIds(id);
  
        for (var i=0; i<ids.length; i++) {
          // Get the sound.
          var sound = self._soundById(ids[i]);
  
          if (sound) {
            sound._muted = muted;
  
            // Cancel active fade and set the volume to the end value.
            if (sound._interval) {
              self._stopFade(sound._id);
            }
  
            if (self._webAudio && sound._node) {
              sound._node.gain.setValueAtTime(muted ? 0 : sound._volume, Howler.ctx.currentTime);
            } else if (sound._node) {
              sound._node.muted = Howler._muted ? true : muted;
            }
  
            self._emit('mute', sound._id);
          }
        }
  
        return self;
      },
  
      /**
       * Get/set the volume of this sound or of the Howl group. This method can optionally take 0, 1 or 2 arguments.
       *   volume() -> Returns the group's volume value.
       *   volume(id) -> Returns the sound id's current volume.
       *   volume(vol) -> Sets the volume of all sounds in this Howl group.
       *   volume(vol, id) -> Sets the volume of passed sound id.
       * @return {Howl/Number} Returns self or current volume.
       */
      volume: function() {
        var self = this;
        var args = arguments;
        var vol, id;
  
        // Determine the values based on arguments.
        if (args.length === 0) {
          // Return the value of the groups' volume.
          return self._volume;
        } else if (args.length === 1 || args.length === 2 && typeof args[1] === 'undefined') {
          // First check if this is an ID, and if not, assume it is a new volume.
          var ids = self._getSoundIds();
          var index = ids.indexOf(args[0]);
          if (index >= 0) {
            id = parseInt(args[0], 10);
          } else {
            vol = parseFloat(args[0]);
          }
        } else if (args.length >= 2) {
          vol = parseFloat(args[0]);
          id = parseInt(args[1], 10);
        }
  
        // Update the volume or return the current volume.
        var sound;
        if (typeof vol !== 'undefined' && vol >= 0 && vol <= 1) {
          // If the sound hasn't loaded, add it to the load queue to change volume when capable.
          if (self._state !== 'loaded'|| self._playLock) {
            self._queue.push({
              event: 'volume',
              action: function() {
                self.volume.apply(self, args);
              }
            });
  
            return self;
          }
  
          // Set the group volume.
          if (typeof id === 'undefined') {
            self._volume = vol;
          }
  
          // Update one or all volumes.
          id = self._getSoundIds(id);
          for (var i=0; i<id.length; i++) {
            // Get the sound.
            sound = self._soundById(id[i]);
  
            if (sound) {
              sound._volume = vol;
  
              // Stop currently running fades.
              if (!args[2]) {
                self._stopFade(id[i]);
              }
  
              if (self._webAudio && sound._node && !sound._muted) {
                sound._node.gain.setValueAtTime(vol, Howler.ctx.currentTime);
              } else if (sound._node && !sound._muted) {
                sound._node.volume = vol * Howler.volume();
              }
  
              self._emit('volume', sound._id);
            }
          }
        } else {
          sound = id ? self._soundById(id) : self._sounds[0];
          return sound ? sound._volume : 0;
        }
  
        return self;
      },
  
      /**
       * Fade a currently playing sound between two volumes (if no id is passsed, all sounds will fade).
       * @param  {Number} from The value to fade from (0.0 to 1.0).
       * @param  {Number} to   The volume to fade to (0.0 to 1.0).
       * @param  {Number} len  Time in milliseconds to fade.
       * @param  {Number} id   The sound id (omit to fade all sounds).
       * @return {Howl}
       */
      fade: function(from, to, len, id) {
        var self = this;
  
        // If the sound hasn't loaded, add it to the load queue to fade when capable.
        if (self._state !== 'loaded' || self._playLock) {
          self._queue.push({
            event: 'fade',
            action: function() {
              self.fade(from, to, len, id);
            }
          });
  
          return self;
        }
  
        // Make sure the to/from/len values are numbers.
        from = parseFloat(from);
        to = parseFloat(to);
        len = parseFloat(len);
  
        // Set the volume to the start position.
        self.volume(from, id);
  
        // Fade the volume of one or all sounds.
        var ids = self._getSoundIds(id);
        for (var i=0; i<ids.length; i++) {
          // Get the sound.
          var sound = self._soundById(ids[i]);
  
          // Create a linear fade or fall back to timeouts with HTML5 Audio.
          if (sound) {
            // Stop the previous fade if no sprite is being used (otherwise, volume handles this).
            if (!id) {
              self._stopFade(ids[i]);
            }
  
            // If we are using Web Audio, let the native methods do the actual fade.
            if (self._webAudio && !sound._muted) {
              var currentTime = Howler.ctx.currentTime;
              var end = currentTime + (len / 1000);
              sound._volume = from;
              sound._node.gain.setValueAtTime(from, currentTime);
              sound._node.gain.linearRampToValueAtTime(to, end);
            }
  
            self._startFadeInterval(sound, from, to, len, ids[i], typeof id === 'undefined');
          }
        }
  
        return self;
      },
  
      /**
       * Starts the internal interval to fade a sound.
       * @param  {Object} sound Reference to sound to fade.
       * @param  {Number} from The value to fade from (0.0 to 1.0).
       * @param  {Number} to   The volume to fade to (0.0 to 1.0).
       * @param  {Number} len  Time in milliseconds to fade.
       * @param  {Number} id   The sound id to fade.
       * @param  {Boolean} isGroup   If true, set the volume on the group.
       */
      _startFadeInterval: function(sound, from, to, len, id, isGroup) {
        var self = this;
        var vol = from;
        var diff = to - from;
        var steps = Math.abs(diff / 0.01);
        var stepLen = Math.max(4, (steps > 0) ? len / steps : len);
        var lastTick = Date.now();
  
        // Store the value being faded to.
        sound._fadeTo = to;
  
        // Update the volume value on each interval tick.
        sound._interval = setInterval(function() {
          // Update the volume based on the time since the last tick.
          var tick = (Date.now() - lastTick) / len;
          lastTick = Date.now();
          vol += diff * tick;
  
          // Make sure the volume is in the right bounds.
          vol = Math.max(0, vol);
          vol = Math.min(1, vol);
  
          // Round to within 2 decimal points.
          vol = Math.round(vol * 100) / 100;
  
          // Change the volume.
          if (self._webAudio) {
            sound._volume = vol;
          } else {
            self.volume(vol, sound._id, true);
          }
  
          // Set the group's volume.
          if (isGroup) {
            self._volume = vol;
          }
  
          // When the fade is complete, stop it and fire event.
          if ((to < from && vol <= to) || (to > from && vol >= to)) {
            clearInterval(sound._interval);
            sound._interval = null;
            sound._fadeTo = null;
            self.volume(to, sound._id);
            self._emit('fade', sound._id);
          }
        }, stepLen);
      },
  
      /**
       * Internal method that stops the currently playing fade when
       * a new fade starts, volume is changed or the sound is stopped.
       * @param  {Number} id The sound id.
       * @return {Howl}
       */
      _stopFade: function(id) {
        var self = this;
        var sound = self._soundById(id);
  
        if (sound && sound._interval) {
          if (self._webAudio) {
            sound._node.gain.cancelScheduledValues(Howler.ctx.currentTime);
          }
  
          clearInterval(sound._interval);
          sound._interval = null;
          self.volume(sound._fadeTo, id);
          sound._fadeTo = null;
          self._emit('fade', id);
        }
  
        return self;
      },
  
      /**
       * Get/set the loop parameter on a sound. This method can optionally take 0, 1 or 2 arguments.
       *   loop() -> Returns the group's loop value.
       *   loop(id) -> Returns the sound id's loop value.
       *   loop(loop) -> Sets the loop value for all sounds in this Howl group.
       *   loop(loop, id) -> Sets the loop value of passed sound id.
       * @return {Howl/Boolean} Returns self or current loop value.
       */
      loop: function() {
        var self = this;
        var args = arguments;
        var loop, id, sound;
  
        // Determine the values for loop and id.
        if (args.length === 0) {
          // Return the grou's loop value.
          return self._loop;
        } else if (args.length === 1) {
          if (typeof args[0] === 'boolean') {
            loop = args[0];
            self._loop = loop;
          } else {
            // Return this sound's loop value.
            sound = self._soundById(parseInt(args[0], 10));
            return sound ? sound._loop : false;
          }
        } else if (args.length === 2) {
          loop = args[0];
          id = parseInt(args[1], 10);
        }
  
        // If no id is passed, get all ID's to be looped.
        var ids = self._getSoundIds(id);
        for (var i=0; i<ids.length; i++) {
          sound = self._soundById(ids[i]);
  
          if (sound) {
            sound._loop = loop;
            if (self._webAudio && sound._node && sound._node.bufferSource) {
              sound._node.bufferSource.loop = loop;
              if (loop) {
                sound._node.bufferSource.loopStart = sound._start || 0;
                sound._node.bufferSource.loopEnd = sound._stop;
              }
            }
          }
        }
  
        return self;
      },
  
      /**
       * Get/set the playback rate of a sound. This method can optionally take 0, 1 or 2 arguments.
       *   rate() -> Returns the first sound node's current playback rate.
       *   rate(id) -> Returns the sound id's current playback rate.
       *   rate(rate) -> Sets the playback rate of all sounds in this Howl group.
       *   rate(rate, id) -> Sets the playback rate of passed sound id.
       * @return {Howl/Number} Returns self or the current playback rate.
       */
      rate: function() {
        var self = this;
        var args = arguments;
        var rate, id;
  
        // Determine the values based on arguments.
        if (args.length === 0) {
          // We will simply return the current rate of the first node.
          id = self._sounds[0]._id;
        } else if (args.length === 1) {
          // First check if this is an ID, and if not, assume it is a new rate value.
          var ids = self._getSoundIds();
          var index = ids.indexOf(args[0]);
          if (index >= 0) {
            id = parseInt(args[0], 10);
          } else {
            rate = parseFloat(args[0]);
          }
        } else if (args.length === 2) {
          rate = parseFloat(args[0]);
          id = parseInt(args[1], 10);
        }
  
        // Update the playback rate or return the current value.
        var sound;
        if (typeof rate === 'number') {
          // If the sound hasn't loaded, add it to the load queue to change playback rate when capable.
          if (self._state !== 'loaded' || self._playLock) {
            self._queue.push({
              event: 'rate',
              action: function() {
                self.rate.apply(self, args);
              }
            });
  
            return self;
          }
  
          // Set the group rate.
          if (typeof id === 'undefined') {
            self._rate = rate;
          }
  
          // Update one or all volumes.
          id = self._getSoundIds(id);
          for (var i=0; i<id.length; i++) {
            // Get the sound.
            sound = self._soundById(id[i]);
  
            if (sound) {
              // Keep track of our position when the rate changed and update the playback
              // start position so we can properly adjust the seek position for time elapsed.
              if (self.playing(id[i])) {
                sound._rateSeek = self.seek(id[i]);
                sound._playStart = self._webAudio ? Howler.ctx.currentTime : sound._playStart;
              }
              sound._rate = rate;
  
              // Change the playback rate.
              if (self._webAudio && sound._node && sound._node.bufferSource) {
                sound._node.bufferSource.playbackRate.setValueAtTime(rate, Howler.ctx.currentTime);
              } else if (sound._node) {
                sound._node.playbackRate = rate;
              }
  
              // Reset the timers.
              var seek = self.seek(id[i]);
              var duration = ((self._sprite[sound._sprite][0] + self._sprite[sound._sprite][1]) / 1000) - seek;
              var timeout = (duration * 1000) / Math.abs(sound._rate);
  
              // Start a new end timer if sound is already playing.
              if (self._endTimers[id[i]] || !sound._paused) {
                self._clearTimer(id[i]);
                self._endTimers[id[i]] = setTimeout(self._ended.bind(self, sound), timeout);
              }
  
              self._emit('rate', sound._id);
            }
          }
        } else {
          sound = self._soundById(id);
          return sound ? sound._rate : self._rate;
        }
  
        return self;
      },
  
      /**
       * Get/set the seek position of a sound. This method can optionally take 0, 1 or 2 arguments.
       *   seek() -> Returns the first sound node's current seek position.
       *   seek(id) -> Returns the sound id's current seek position.
       *   seek(seek) -> Sets the seek position of the first sound node.
       *   seek(seek, id) -> Sets the seek position of passed sound id.
       * @return {Howl/Number} Returns self or the current seek position.
       */
      seek: function() {
        var self = this;
        var args = arguments;
        var seek, id;
  
        // Determine the values based on arguments.
        if (args.length === 0) {
          // We will simply return the current position of the first node.
          id = self._sounds[0]._id;
        } else if (args.length === 1) {
          // First check if this is an ID, and if not, assume it is a new seek position.
          var ids = self._getSoundIds();
          var index = ids.indexOf(args[0]);
          if (index >= 0) {
            id = parseInt(args[0], 10);
          } else if (self._sounds.length) {
            id = self._sounds[0]._id;
            seek = parseFloat(args[0]);
          }
        } else if (args.length === 2) {
          seek = parseFloat(args[0]);
          id = parseInt(args[1], 10);
        }
  
        // If there is no ID, bail out.
        if (typeof id === 'undefined') {
          return self;
        }
  
        // If the sound hasn't loaded, add it to the load queue to seek when capable.
        if (self._state !== 'loaded' || self._playLock) {
          self._queue.push({
            event: 'seek',
            action: function() {
              self.seek.apply(self, args);
            }
          });
  
          return self;
        }
  
        // Get the sound.
        var sound = self._soundById(id);
  
        if (sound) {
          if (typeof seek === 'number' && seek >= 0) {
            // Pause the sound and update position for restarting playback.
            var playing = self.playing(id);
            if (playing) {
              self.pause(id, true);
            }
  
            // Move the position of the track and cancel timer.
            sound._seek = seek;
            sound._ended = false;
            self._clearTimer(id);
  
            // Update the seek position for HTML5 Audio.
            if (!self._webAudio && sound._node && !isNaN(sound._node.duration)) {
              sound._node.currentTime = seek;
            }
  
            // Seek and emit when ready.
            var seekAndEmit = function() {
              self._emit('seek', id);
  
              // Restart the playback if the sound was playing.
              if (playing) {
                self.play(id, true);
              }
            };
  
            // Wait for the play lock to be unset before emitting (HTML5 Audio).
            if (playing && !self._webAudio) {
              var emitSeek = function() {
                if (!self._playLock) {
                  seekAndEmit();
                } else {
                  setTimeout(emitSeek, 0);
                }
              };
              setTimeout(emitSeek, 0);
            } else {
              seekAndEmit();
            }
          } else {
            if (self._webAudio) {
              var realTime = self.playing(id) ? Howler.ctx.currentTime - sound._playStart : 0;
              var rateSeek = sound._rateSeek ? sound._rateSeek - sound._seek : 0;
              return sound._seek + (rateSeek + realTime * Math.abs(sound._rate));
            } else {
              return sound._node.currentTime;
            }
          }
        }
  
        return self;
      },
  
      /**
       * Check if a specific sound is currently playing or not (if id is provided), or check if at least one of the sounds in the group is playing or not.
       * @param  {Number}  id The sound id to check. If none is passed, the whole sound group is checked.
       * @return {Boolean} True if playing and false if not.
       */
      playing: function(id) {
        var self = this;
  
        // Check the passed sound ID (if any).
        if (typeof id === 'number') {
          var sound = self._soundById(id);
          return sound ? !sound._paused : false;
        }
  
        // Otherwise, loop through all sounds and check if any are playing.
        for (var i=0; i<self._sounds.length; i++) {
          if (!self._sounds[i]._paused) {
            return true;
          }
        }
  
        return false;
      },
  
      /**
       * Get the duration of this sound. Passing a sound id will return the sprite duration.
       * @param  {Number} id The sound id to check. If none is passed, return full source duration.
       * @return {Number} Audio duration in seconds.
       */
      duration: function(id) {
        var self = this;
        var duration = self._duration;
  
        // If we pass an ID, get the sound and return the sprite length.
        var sound = self._soundById(id);
        if (sound) {
          duration = self._sprite[sound._sprite][1] / 1000;
        }
  
        return duration;
      },
  
      /**
       * Returns the current loaded state of this Howl.
       * @return {String} 'unloaded', 'loading', 'loaded'
       */
      state: function() {
        return this._state;
      },
  
      /**
       * Unload and destroy the current Howl object.
       * This will immediately stop all sound instances attached to this group.
       */
      unload: function() {
        var self = this;
  
        // Stop playing any active sounds.
        var sounds = self._sounds;
        for (var i=0; i<sounds.length; i++) {
          // Stop the sound if it is currently playing.
          if (!sounds[i]._paused) {
            self.stop(sounds[i]._id);
          }
  
          // Remove the source or disconnect.
          if (!self._webAudio) {
            // Set the source to 0-second silence to stop any downloading (except in IE).
            self._clearSound(sounds[i]._node);
  
            // Remove any event listeners.
            sounds[i]._node.removeEventListener('error', sounds[i]._errorFn, false);
            sounds[i]._node.removeEventListener(Howler._canPlayEvent, sounds[i]._loadFn, false);
  
            // Release the Audio object back to the pool.
            Howler._releaseHtml5Audio(sounds[i]._node);
          }
  
          // Empty out all of the nodes.
          delete sounds[i]._node;
  
          // Make sure all timers are cleared out.
          self._clearTimer(sounds[i]._id);
        }
  
        // Remove the references in the global Howler object.
        var index = Howler._howls.indexOf(self);
        if (index >= 0) {
          Howler._howls.splice(index, 1);
        }
  
        // Delete this sound from the cache (if no other Howl is using it).
        var remCache = true;
        for (i=0; i<Howler._howls.length; i++) {
          if (Howler._howls[i]._src === self._src || self._src.indexOf(Howler._howls[i]._src) >= 0) {
            remCache = false;
            break;
          }
        }
  
        if (cache && remCache) {
          delete cache[self._src];
        }
  
        // Clear global errors.
        Howler.noAudio = false;
  
        // Clear out `self`.
        self._state = 'unloaded';
        self._sounds = [];
        self = null;
  
        return null;
      },
  
      /**
       * Listen to a custom event.
       * @param  {String}   event Event name.
       * @param  {Function} fn    Listener to call.
       * @param  {Number}   id    (optional) Only listen to events for this sound.
       * @param  {Number}   once  (INTERNAL) Marks event to fire only once.
       * @return {Howl}
       */
      on: function(event, fn, id, once) {
        var self = this;
        var events = self['_on' + event];
  
        if (typeof fn === 'function') {
          events.push(once ? {id: id, fn: fn, once: once} : {id: id, fn: fn});
        }
  
        return self;
      },
  
      /**
       * Remove a custom event. Call without parameters to remove all events.
       * @param  {String}   event Event name.
       * @param  {Function} fn    Listener to remove. Leave empty to remove all.
       * @param  {Number}   id    (optional) Only remove events for this sound.
       * @return {Howl}
       */
      off: function(event, fn, id) {
        var self = this;
        var events = self['_on' + event];
        var i = 0;
  
        // Allow passing just an event and ID.
        if (typeof fn === 'number') {
          id = fn;
          fn = null;
        }
  
        if (fn || id) {
          // Loop through event store and remove the passed function.
          for (i=0; i<events.length; i++) {
            var isId = (id === events[i].id);
            if (fn === events[i].fn && isId || !fn && isId) {
              events.splice(i, 1);
              break;
            }
          }
        } else if (event) {
          // Clear out all events of this type.
          self['_on' + event] = [];
        } else {
          // Clear out all events of every type.
          var keys = Object.keys(self);
          for (i=0; i<keys.length; i++) {
            if ((keys[i].indexOf('_on') === 0) && Array.isArray(self[keys[i]])) {
              self[keys[i]] = [];
            }
          }
        }
  
        return self;
      },
  
      /**
       * Listen to a custom event and remove it once fired.
       * @param  {String}   event Event name.
       * @param  {Function} fn    Listener to call.
       * @param  {Number}   id    (optional) Only listen to events for this sound.
       * @return {Howl}
       */
      once: function(event, fn, id) {
        var self = this;
  
        // Setup the event listener.
        self.on(event, fn, id, 1);
  
        return self;
      },
  
      /**
       * Emit all events of a specific type and pass the sound id.
       * @param  {String} event Event name.
       * @param  {Number} id    Sound ID.
       * @param  {Number} msg   Message to go with event.
       * @return {Howl}
       */
      _emit: function(event, id, msg) {
        var self = this;
        var events = self['_on' + event];
  
        // Loop through event store and fire all functions.
        for (var i=events.length-1; i>=0; i--) {
          // Only fire the listener if the correct ID is used.
          if (!events[i].id || events[i].id === id || event === 'load') {
            setTimeout(function(fn) {
              fn.call(this, id, msg);
            }.bind(self, events[i].fn), 0);
  
            // If this event was setup with `once`, remove it.
            if (events[i].once) {
              self.off(event, events[i].fn, events[i].id);
            }
          }
        }
  
        // Pass the event type into load queue so that it can continue stepping.
        self._loadQueue(event);
  
        return self;
      },
  
      /**
       * Queue of actions initiated before the sound has loaded.
       * These will be called in sequence, with the next only firing
       * after the previous has finished executing (even if async like play).
       * @return {Howl}
       */
      _loadQueue: function(event) {
        var self = this;
  
        if (self._queue.length > 0) {
          var task = self._queue[0];
  
          // Remove this task if a matching event was passed.
          if (task.event === event) {
            self._queue.shift();
            self._loadQueue();
          }
  
          // Run the task if no event type is passed.
          if (!event) {
            task.action();
          }
        }
  
        return self;
      },
  
      /**
       * Fired when playback ends at the end of the duration.
       * @param  {Sound} sound The sound object to work with.
       * @return {Howl}
       */
      _ended: function(sound) {
        var self = this;
        var sprite = sound._sprite;
  
        // If we are using IE and there was network latency we may be clipping
        // audio before it completes playing. Lets check the node to make sure it
        // believes it has completed, before ending the playback.
        if (!self._webAudio && sound._node && !sound._node.paused && !sound._node.ended && sound._node.currentTime < sound._stop) {
          setTimeout(self._ended.bind(self, sound), 100);
          return self;
        }
  
        // Should this sound loop?
        var loop = !!(sound._loop || self._sprite[sprite][2]);
  
        // Fire the ended event.
        self._emit('end', sound._id);
  
        // Restart the playback for HTML5 Audio loop.
        if (!self._webAudio && loop) {
          self.stop(sound._id, true).play(sound._id);
        }
  
        // Restart this timer if on a Web Audio loop.
        if (self._webAudio && loop) {
          self._emit('play', sound._id);
          sound._seek = sound._start || 0;
          sound._rateSeek = 0;
          sound._playStart = Howler.ctx.currentTime;
  
          var timeout = ((sound._stop - sound._start) * 1000) / Math.abs(sound._rate);
          self._endTimers[sound._id] = setTimeout(self._ended.bind(self, sound), timeout);
        }
  
        // Mark the node as paused.
        if (self._webAudio && !loop) {
          sound._paused = true;
          sound._ended = true;
          sound._seek = sound._start || 0;
          sound._rateSeek = 0;
          self._clearTimer(sound._id);
  
          // Clean up the buffer source.
          self._cleanBuffer(sound._node);
  
          // Attempt to auto-suspend AudioContext if no sounds are still playing.
          Howler._autoSuspend();
        }
  
        // When using a sprite, end the track.
        if (!self._webAudio && !loop) {
          self.stop(sound._id, true);
        }
  
        return self;
      },
  
      /**
       * Clear the end timer for a sound playback.
       * @param  {Number} id The sound ID.
       * @return {Howl}
       */
      _clearTimer: function(id) {
        var self = this;
  
        if (self._endTimers[id]) {
          // Clear the timeout or remove the ended listener.
          if (typeof self._endTimers[id] !== 'function') {
            clearTimeout(self._endTimers[id]);
          } else {
            var sound = self._soundById(id);
            if (sound && sound._node) {
              sound._node.removeEventListener('ended', self._endTimers[id], false);
            }
          }
  
          delete self._endTimers[id];
        }
  
        return self;
      },
  
      /**
       * Return the sound identified by this ID, or return null.
       * @param  {Number} id Sound ID
       * @return {Object}    Sound object or null.
       */
      _soundById: function(id) {
        var self = this;
  
        // Loop through all sounds and find the one with this ID.
        for (var i=0; i<self._sounds.length; i++) {
          if (id === self._sounds[i]._id) {
            return self._sounds[i];
          }
        }
  
        return null;
      },
  
      /**
       * Return an inactive sound from the pool or create a new one.
       * @return {Sound} Sound playback object.
       */
      _inactiveSound: function() {
        var self = this;
  
        self._drain();
  
        // Find the first inactive node to recycle.
        for (var i=0; i<self._sounds.length; i++) {
          if (self._sounds[i]._ended) {
            return self._sounds[i].reset();
          }
        }
  
        // If no inactive node was found, create a new one.
        return new Sound(self);
      },
  
      /**
       * Drain excess inactive sounds from the pool.
       */
      _drain: function() {
        var self = this;
        var limit = self._pool;
        var cnt = 0;
        var i = 0;
  
        // If there are less sounds than the max pool size, we are done.
        if (self._sounds.length < limit) {
          return;
        }
  
        // Count the number of inactive sounds.
        for (i=0; i<self._sounds.length; i++) {
          if (self._sounds[i]._ended) {
            cnt++;
          }
        }
  
        // Remove excess inactive sounds, going in reverse order.
        for (i=self._sounds.length - 1; i>=0; i--) {
          if (cnt <= limit) {
            return;
          }
  
          if (self._sounds[i]._ended) {
            // Disconnect the audio source when using Web Audio.
            if (self._webAudio && self._sounds[i]._node) {
              self._sounds[i]._node.disconnect(0);
            }
  
            // Remove sounds until we have the pool size.
            self._sounds.splice(i, 1);
            cnt--;
          }
        }
      },
  
      /**
       * Get all ID's from the sounds pool.
       * @param  {Number} id Only return one ID if one is passed.
       * @return {Array}    Array of IDs.
       */
      _getSoundIds: function(id) {
        var self = this;
  
        if (typeof id === 'undefined') {
          var ids = [];
          for (var i=0; i<self._sounds.length; i++) {
            ids.push(self._sounds[i]._id);
          }
  
          return ids;
        } else {
          return [id];
        }
      },
  
      /**
       * Load the sound back into the buffer source.
       * @param  {Sound} sound The sound object to work with.
       * @return {Howl}
       */
      _refreshBuffer: function(sound) {
        var self = this;
  
        // Setup the buffer source for playback.
        sound._node.bufferSource = Howler.ctx.createBufferSource();
        sound._node.bufferSource.buffer = cache[self._src];
  
        // Connect to the correct node.
        if (sound._panner) {
          sound._node.bufferSource.connect(sound._panner);
        } else {
          sound._node.bufferSource.connect(sound._node);
        }
  
        // Setup looping and playback rate.
        sound._node.bufferSource.loop = sound._loop;
        if (sound._loop) {
          sound._node.bufferSource.loopStart = sound._start || 0;
          sound._node.bufferSource.loopEnd = sound._stop || 0;
        }
        sound._node.bufferSource.playbackRate.setValueAtTime(sound._rate, Howler.ctx.currentTime);
  
        return self;
      },
  
      /**
       * Prevent memory leaks by cleaning up the buffer source after playback.
       * @param  {Object} node Sound's audio node containing the buffer source.
       * @return {Howl}
       */
      _cleanBuffer: function(node) {
        var self = this;
        var isIOS = Howler._navigator && Howler._navigator.vendor.indexOf('Apple') >= 0;
  
        if (Howler._scratchBuffer && node.bufferSource) {
          node.bufferSource.onended = null;
          node.bufferSource.disconnect(0);
          if (isIOS) {
            try { node.bufferSource.buffer = Howler._scratchBuffer; } catch(e) {}
          }
        }
        node.bufferSource = null;
  
        return self;
      },
  
      /**
       * Set the source to a 0-second silence to stop any downloading (except in IE).
       * @param  {Object} node Audio node to clear.
       */
      _clearSound: function(node) {
        var checkIE = /MSIE |Trident\//.test(Howler._navigator && Howler._navigator.userAgent);
        if (!checkIE) {
          node.src = 'data:audio/wav;base64,UklGRigAAABXQVZFZm10IBIAAAABAAEARKwAAIhYAQACABAAAABkYXRhAgAAAAEA';
        }
      }
    };
  
    /** Single Sound Methods **/
    /***************************************************************************/
  
    /**
     * Setup the sound object, which each node attached to a Howl group is contained in.
     * @param {Object} howl The Howl parent group.
     */
    var Sound = function(howl) {
      this._parent = howl;
      this.init();
    };
    Sound.prototype = {
      /**
       * Initialize a new Sound object.
       * @return {Sound}
       */
      init: function() {
        var self = this;
        var parent = self._parent;
  
        // Setup the default parameters.
        self._muted = parent._muted;
        self._loop = parent._loop;
        self._volume = parent._volume;
        self._rate = parent._rate;
        self._seek = 0;
        self._paused = true;
        self._ended = true;
        self._sprite = '__default';
  
        // Generate a unique ID for this sound.
        self._id = ++Howler._counter;
  
        // Add itself to the parent's pool.
        parent._sounds.push(self);
  
        // Create the new node.
        self.create();
  
        return self;
      },
  
      /**
       * Create and setup a new sound object, whether HTML5 Audio or Web Audio.
       * @return {Sound}
       */
      create: function() {
        var self = this;
        var parent = self._parent;
        var volume = (Howler._muted || self._muted || self._parent._muted) ? 0 : self._volume;
  
        if (parent._webAudio) {
          // Create the gain node for controlling volume (the source will connect to this).
          self._node = (typeof Howler.ctx.createGain === 'undefined') ? Howler.ctx.createGainNode() : Howler.ctx.createGain();
          self._node.gain.setValueAtTime(volume, Howler.ctx.currentTime);
          self._node.paused = true;
          self._node.connect(Howler.masterGain);
        } else {
          // Get an unlocked Audio object from the pool.
          self._node = Howler._obtainHtml5Audio();
  
          // Listen for errors (http://dev.w3.org/html5/spec-author-view/spec.html#mediaerror).
          self._errorFn = self._errorListener.bind(self);
          self._node.addEventListener('error', self._errorFn, false);
  
          // Listen for 'canplaythrough' event to let us know the sound is ready.
          self._loadFn = self._loadListener.bind(self);
          self._node.addEventListener(Howler._canPlayEvent, self._loadFn, false);
  
          // Setup the new audio node.
          self._node.src = parent._src;
          self._node.preload = 'auto';
          self._node.volume = volume * Howler.volume();
  
          // Begin loading the source.
          self._node.load();
        }
  
        return self;
      },
  
      /**
       * Reset the parameters of this sound to the original state (for recycle).
       * @return {Sound}
       */
      reset: function() {
        var self = this;
        var parent = self._parent;
  
        // Reset all of the parameters of this sound.
        self._muted = parent._muted;
        self._loop = parent._loop;
        self._volume = parent._volume;
        self._rate = parent._rate;
        self._seek = 0;
        self._rateSeek = 0;
        self._paused = true;
        self._ended = true;
        self._sprite = '__default';
  
        // Generate a new ID so that it isn't confused with the previous sound.
        self._id = ++Howler._counter;
  
        return self;
      },
  
      /**
       * HTML5 Audio error listener callback.
       */
      _errorListener: function() {
        var self = this;
  
        // Fire an error event and pass back the code.
        self._parent._emit('loaderror', self._id, self._node.error ? self._node.error.code : 0);
  
        // Clear the event listener.
        self._node.removeEventListener('error', self._errorFn, false);
      },
  
      /**
       * HTML5 Audio canplaythrough listener callback.
       */
      _loadListener: function() {
        var self = this;
        var parent = self._parent;
  
        // Round up the duration to account for the lower precision in HTML5 Audio.
        parent._duration = Math.ceil(self._node.duration * 10) / 10;
  
        // Setup a sprite if none is defined.
        if (Object.keys(parent._sprite).length === 0) {
          parent._sprite = {__default: [0, parent._duration * 1000]};
        }
  
        if (parent._state !== 'loaded') {
          parent._state = 'loaded';
          parent._emit('load');
          parent._loadQueue();
        }
  
        // Clear the event listener.
        self._node.removeEventListener(Howler._canPlayEvent, self._loadFn, false);
      }
    };
  
    /** Helper Methods **/
    /***************************************************************************/
  
    var cache = {};
  
    /**
     * Buffer a sound from URL, Data URI or cache and decode to audio source (Web Audio API).
     * @param  {Howl} self
     */
    var loadBuffer = function(self) {
      var url = self._src;
  
      // Check if the buffer has already been cached and use it instead.
      if (cache[url]) {
        // Set the duration from the cache.
        self._duration = cache[url].duration;
  
        // Load the sound into this Howl.
        loadSound(self);
  
        return;
      }
  
      if (/^data:[^;]+;base64,/.test(url)) {
        // Decode the base64 data URI without XHR, since some browsers don't support it.
        var data = atob(url.split(',')[1]);
        var dataView = new Uint8Array(data.length);
        for (var i=0; i<data.length; ++i) {
          dataView[i] = data.charCodeAt(i);
        }
  
        decodeAudioData(dataView.buffer, self);
      } else {
        // Load the buffer from the URL.
        var xhr = new XMLHttpRequest();
        xhr.open('GET', url, true);
        xhr.withCredentials = self._xhrWithCredentials;
        xhr.responseType = 'arraybuffer';
        xhr.onload = function() {
          // Make sure we get a successful response back.
          var code = (xhr.status + '')[0];
          if (code !== '0' && code !== '2' && code !== '3') {
            self._emit('loaderror', null, 'Failed loading audio file with status: ' + xhr.status + '.');
            return;
          }
  
          decodeAudioData(xhr.response, self);
        };
        xhr.onerror = function() {
          // If there is an error, switch to HTML5 Audio.
          if (self._webAudio) {
            self._html5 = true;
            self._webAudio = false;
            self._sounds = [];
            delete cache[url];
            self.load();
          }
        };
        safeXhrSend(xhr);
      }
    };
  
    /**
     * Send the XHR request wrapped in a try/catch.
     * @param  {Object} xhr XHR to send.
     */
    var safeXhrSend = function(xhr) {
      try {
        xhr.send();
      } catch (e) {
        xhr.onerror();
      }
    };
  
    /**
     * Decode audio data from an array buffer.
     * @param  {ArrayBuffer} arraybuffer The audio data.
     * @param  {Howl}        self
     */
    var decodeAudioData = function(arraybuffer, self) {
      // Fire a load error if something broke.
      var error = function() {
        self._emit('loaderror', null, 'Decoding audio data failed.');
      };
  
      // Load the sound on success.
      var success = function(buffer) {
        if (buffer && self._sounds.length > 0) {
          cache[self._src] = buffer;
          loadSound(self, buffer);
        } else {
          error();
        }
      };
  
      // Decode the buffer into an audio source.
      if (typeof Promise !== 'undefined' && Howler.ctx.decodeAudioData.length === 1) {
        Howler.ctx.decodeAudioData(arraybuffer).then(success).catch(error);
      } else {
        Howler.ctx.decodeAudioData(arraybuffer, success, error);
      }
    }
  
    /**
     * Sound is now loaded, so finish setting everything up and fire the loaded event.
     * @param  {Howl} self
     * @param  {Object} buffer The decoded buffer sound source.
     */
    var loadSound = function(self, buffer) {
      // Set the duration.
      if (buffer && !self._duration) {
        self._duration = buffer.duration;
      }
  
      // Setup a sprite if none is defined.
      if (Object.keys(self._sprite).length === 0) {
        self._sprite = {__default: [0, self._duration * 1000]};
      }
  
      // Fire the loaded event.
      if (self._state !== 'loaded') {
        self._state = 'loaded';
        self._emit('load');
        self._loadQueue();
      }
    };
  
    /**
     * Setup the audio context when available, or switch to HTML5 Audio mode.
     */
    var setupAudioContext = function() {
      // If we have already detected that Web Audio isn't supported, don't run this step again.
      if (!Howler.usingWebAudio) {
        return;
      }
  
      // Check if we are using Web Audio and setup the AudioContext if we are.
      try {
        if (typeof AudioContext !== 'undefined') {
          Howler.ctx = new AudioContext();
        } else if (typeof webkitAudioContext !== 'undefined') {
          Howler.ctx = new webkitAudioContext();
        } else {
          Howler.usingWebAudio = false;
        }
      } catch(e) {
        Howler.usingWebAudio = false;
      }
  
      // If the audio context creation still failed, set using web audio to false.
      if (!Howler.ctx) {
        Howler.usingWebAudio = false;
      }
  
      // Check if a webview is being used on iOS8 or earlier (rather than the browser).
      // If it is, disable Web Audio as it causes crashing.
      var iOS = (/iP(hone|od|ad)/.test(Howler._navigator && Howler._navigator.platform));
      var appVersion = Howler._navigator && Howler._navigator.appVersion.match(/OS (\d+)_(\d+)_?(\d+)?/);
      var version = appVersion ? parseInt(appVersion[1], 10) : null;
      if (iOS && version && version < 9) {
        var safari = /safari/.test(Howler._navigator && Howler._navigator.userAgent.toLowerCase());
        if (Howler._navigator && Howler._navigator.standalone && !safari || Howler._navigator && !Howler._navigator.standalone && !safari) {
          Howler.usingWebAudio = false;
        }
      }
  
      // Create and expose the master GainNode when using Web Audio (useful for plugins or advanced usage).
      if (Howler.usingWebAudio) {
        Howler.masterGain = (typeof Howler.ctx.createGain === 'undefined') ? Howler.ctx.createGainNode() : Howler.ctx.createGain();
        Howler.masterGain.gain.setValueAtTime(Howler._muted ? 0 : 1, Howler.ctx.currentTime);
        Howler.masterGain.connect(Howler.ctx.destination);
      }
  
      // Re-run the setup on Howler.
      Howler._setup();
    };
  
    // Add support for AMD (Asynchronous Module Definition) libraries such as require.js.
    if (typeof define === 'function' && define.amd) {
      define([], function() {
        return {
          Howler: Howler,
          Howl: Howl
        };
      });
    }
  
    // Add support for CommonJS libraries such as browserify.
    if (typeof exports !== 'undefined') {
      exports.Howler = Howler;
      exports.Howl = Howl;
    }
  
    // Define globally in case AMD is not available or unused.
    if (typeof window !== 'undefined') {
      window.HowlerGlobal = HowlerGlobal;
      window.Howler = Howler;
      window.Howl = Howl;
      window.Sound = Sound;
    } else if (typeof global !== 'undefined') { // Add to global in Node.js (for testing, etc).
      global.HowlerGlobal = HowlerGlobal;
      global.Howler = Howler;
      global.Howl = Howl;
      global.Sound = Sound;
    }
  })();
  
  
  /*!
   *  Spatial Plugin - Adds support for stereo and 3D audio where Web Audio is supported.
   *  
   *  howler.js v2.1.2
   *  howlerjs.com
   *
   *  (c) 2013-2019, James Simpson of GoldFire Studios
   *  goldfirestudios.com
   *
   *  MIT License
   */
  
  (function() {
  
    'use strict';
  
    // Setup default properties.
    HowlerGlobal.prototype._pos = [0, 0, 0];
    HowlerGlobal.prototype._orientation = [0, 0, -1, 0, 1, 0];
  
    /** Global Methods **/
    /***************************************************************************/
  
    /**
     * Helper method to update the stereo panning position of all current Howls.
     * Future Howls will not use this value unless explicitly set.
     * @param  {Number} pan A value of -1.0 is all the way left and 1.0 is all the way right.
     * @return {Howler/Number}     Self or current stereo panning value.
     */
    HowlerGlobal.prototype.stereo = function(pan) {
      var self = this;
  
      // Stop right here if not using Web Audio.
      if (!self.ctx || !self.ctx.listener) {
        return self;
      }
  
      // Loop through all Howls and update their stereo panning.
      for (var i=self._howls.length-1; i>=0; i--) {
        self._howls[i].stereo(pan);
      }
  
      return self;
    };
  
    /**
     * Get/set the position of the listener in 3D cartesian space. Sounds using
     * 3D position will be relative to the listener's position.
     * @param  {Number} x The x-position of the listener.
     * @param  {Number} y The y-position of the listener.
     * @param  {Number} z The z-position of the listener.
     * @return {Howler/Array}   Self or current listener position.
     */
    HowlerGlobal.prototype.pos = function(x, y, z) {
      var self = this;
  
      // Stop right here if not using Web Audio.
      if (!self.ctx || !self.ctx.listener) {
        return self;
      }
  
      // Set the defaults for optional 'y' & 'z'.
      y = (typeof y !== 'number') ? self._pos[1] : y;
      z = (typeof z !== 'number') ? self._pos[2] : z;
  
      if (typeof x === 'number') {
        self._pos = [x, y, z];
  
        if (typeof self.ctx.listener.positionX !== 'undefined') {
          self.ctx.listener.positionX.setTargetAtTime(self._pos[0], Howler.ctx.currentTime, 0.1);
          self.ctx.listener.positionY.setTargetAtTime(self._pos[1], Howler.ctx.currentTime, 0.1);
          self.ctx.listener.positionZ.setTargetAtTime(self._pos[2], Howler.ctx.currentTime, 0.1);
        } else {
          self.ctx.listener.setPosition(self._pos[0], self._pos[1], self._pos[2]);
        }
      } else {
        return self._pos;
      }
  
      return self;
    };
  
    /**
     * Get/set the direction the listener is pointing in the 3D cartesian space.
     * A front and up vector must be provided. The front is the direction the
     * face of the listener is pointing, and up is the direction the top of the
     * listener is pointing. Thus, these values are expected to be at right angles
     * from each other.
     * @param  {Number} x   The x-orientation of the listener.
     * @param  {Number} y   The y-orientation of the listener.
     * @param  {Number} z   The z-orientation of the listener.
     * @param  {Number} xUp The x-orientation of the top of the listener.
     * @param  {Number} yUp The y-orientation of the top of the listener.
     * @param  {Number} zUp The z-orientation of the top of the listener.
     * @return {Howler/Array}     Returns self or the current orientation vectors.
     */
    HowlerGlobal.prototype.orientation = function(x, y, z, xUp, yUp, zUp) {
      var self = this;
  
      // Stop right here if not using Web Audio.
      if (!self.ctx || !self.ctx.listener) {
        return self;
      }
  
      // Set the defaults for optional 'y' & 'z'.
      var or = self._orientation;
      y = (typeof y !== 'number') ? or[1] : y;
      z = (typeof z !== 'number') ? or[2] : z;
      xUp = (typeof xUp !== 'number') ? or[3] : xUp;
      yUp = (typeof yUp !== 'number') ? or[4] : yUp;
      zUp = (typeof zUp !== 'number') ? or[5] : zUp;
  
      if (typeof x === 'number') {
        self._orientation = [x, y, z, xUp, yUp, zUp];
  
        if (typeof self.ctx.listener.forwardX !== 'undefined') {
          self.ctx.listener.forwardX.setTargetAtTime(x, Howler.ctx.currentTime, 0.1);
          self.ctx.listener.forwardY.setTargetAtTime(y, Howler.ctx.currentTime, 0.1);
          self.ctx.listener.forwardZ.setTargetAtTime(z, Howler.ctx.currentTime, 0.1);
          self.ctx.listener.upX.setTargetAtTime(x, Howler.ctx.currentTime, 0.1);
          self.ctx.listener.upY.setTargetAtTime(y, Howler.ctx.currentTime, 0.1);
          self.ctx.listener.upZ.setTargetAtTime(z, Howler.ctx.currentTime, 0.1);
        } else {
          self.ctx.listener.setOrientation(x, y, z, xUp, yUp, zUp);
        }
      } else {
        return or;
      }
  
      return self;
    };
  
    /** Group Methods **/
    /***************************************************************************/
  
    /**
     * Add new properties to the core init.
     * @param  {Function} _super Core init method.
     * @return {Howl}
     */
    Howl.prototype.init = (function(_super) {
      return function(o) {
        var self = this;
  
        // Setup user-defined default properties.
        self._orientation = o.orientation || [1, 0, 0];
        self._stereo = o.stereo || null;
        self._pos = o.pos || null;
        self._pannerAttr = {
          coneInnerAngle: typeof o.coneInnerAngle !== 'undefined' ? o.coneInnerAngle : 360,
          coneOuterAngle: typeof o.coneOuterAngle !== 'undefined' ? o.coneOuterAngle : 360,
          coneOuterGain: typeof o.coneOuterGain !== 'undefined' ? o.coneOuterGain : 0,
          distanceModel: typeof o.distanceModel !== 'undefined' ? o.distanceModel : 'inverse',
          maxDistance: typeof o.maxDistance !== 'undefined' ? o.maxDistance : 10000,
          panningModel: typeof o.panningModel !== 'undefined' ? o.panningModel : 'HRTF',
          refDistance: typeof o.refDistance !== 'undefined' ? o.refDistance : 1,
          rolloffFactor: typeof o.rolloffFactor !== 'undefined' ? o.rolloffFactor : 1
        };
  
        // Setup event listeners.
        self._onstereo = o.onstereo ? [{fn: o.onstereo}] : [];
        self._onpos = o.onpos ? [{fn: o.onpos}] : [];
        self._onorientation = o.onorientation ? [{fn: o.onorientation}] : [];
  
        // Complete initilization with howler.js core's init function.
        return _super.call(this, o);
      };
    })(Howl.prototype.init);
  
    /**
     * Get/set the stereo panning of the audio source for this sound or all in the group.
     * @param  {Number} pan  A value of -1.0 is all the way left and 1.0 is all the way right.
     * @param  {Number} id (optional) The sound ID. If none is passed, all in group will be updated.
     * @return {Howl/Number}    Returns self or the current stereo panning value.
     */
    Howl.prototype.stereo = function(pan, id) {
      var self = this;
  
      // Stop right here if not using Web Audio.
      if (!self._webAudio) {
        return self;
      }
  
      // If the sound hasn't loaded, add it to the load queue to change stereo pan when capable.
      if (self._state !== 'loaded') {
        self._queue.push({
          event: 'stereo',
          action: function() {
            self.stereo(pan, id);
          }
        });
  
        return self;
      }
  
      // Check for PannerStereoNode support and fallback to PannerNode if it doesn't exist.
      var pannerType = (typeof Howler.ctx.createStereoPanner === 'undefined') ? 'spatial' : 'stereo';
  
      // Setup the group's stereo panning if no ID is passed.
      if (typeof id === 'undefined') {
        // Return the group's stereo panning if no parameters are passed.
        if (typeof pan === 'number') {
          self._stereo = pan;
          self._pos = [pan, 0, 0];
        } else {
          return self._stereo;
        }
      }
  
      // Change the streo panning of one or all sounds in group.
      var ids = self._getSoundIds(id);
      for (var i=0; i<ids.length; i++) {
        // Get the sound.
        var sound = self._soundById(ids[i]);
  
        if (sound) {
          if (typeof pan === 'number') {
            sound._stereo = pan;
            sound._pos = [pan, 0, 0];
  
            if (sound._node) {
              // If we are falling back, make sure the panningModel is equalpower.
              sound._pannerAttr.panningModel = 'equalpower';
  
              // Check if there is a panner setup and create a new one if not.
              if (!sound._panner || !sound._panner.pan) {
                setupPanner(sound, pannerType);
              }
  
              if (pannerType === 'spatial') {
                if (typeof sound._panner.positionX !== 'undefined') {
                  sound._panner.positionX.setValueAtTime(pan, Howler.ctx.currentTime);
                  sound._panner.positionY.setValueAtTime(0, Howler.ctx.currentTime);
                  sound._panner.positionZ.setValueAtTime(0, Howler.ctx.currentTime);
                } else {
                  sound._panner.setPosition(pan, 0, 0);
                }
              } else {
                sound._panner.pan.setValueAtTime(pan, Howler.ctx.currentTime);
              }
            }
  
            self._emit('stereo', sound._id);
          } else {
            return sound._stereo;
          }
        }
      }
  
      return self;
    };
  
    /**
     * Get/set the 3D spatial position of the audio source for this sound or group relative to the global listener.
     * @param  {Number} x  The x-position of the audio source.
     * @param  {Number} y  The y-position of the audio source.
     * @param  {Number} z  The z-position of the audio source.
     * @param  {Number} id (optional) The sound ID. If none is passed, all in group will be updated.
     * @return {Howl/Array}    Returns self or the current 3D spatial position: [x, y, z].
     */
    Howl.prototype.pos = function(x, y, z, id) {
      var self = this;
  
      // Stop right here if not using Web Audio.
      if (!self._webAudio) {
        return self;
      }
  
      // If the sound hasn't loaded, add it to the load queue to change position when capable.
      if (self._state !== 'loaded') {
        self._queue.push({
          event: 'pos',
          action: function() {
            self.pos(x, y, z, id);
          }
        });
  
        return self;
      }
  
      // Set the defaults for optional 'y' & 'z'.
      y = (typeof y !== 'number') ? 0 : y;
      z = (typeof z !== 'number') ? -0.5 : z;
  
      // Setup the group's spatial position if no ID is passed.
      if (typeof id === 'undefined') {
        // Return the group's spatial position if no parameters are passed.
        if (typeof x === 'number') {
          self._pos = [x, y, z];
        } else {
          return self._pos;
        }
      }
  
      // Change the spatial position of one or all sounds in group.
      var ids = self._getSoundIds(id);
      for (var i=0; i<ids.length; i++) {
        // Get the sound.
        var sound = self._soundById(ids[i]);
  
        if (sound) {
          if (typeof x === 'number') {
            sound._pos = [x, y, z];
  
            if (sound._node) {
              // Check if there is a panner setup and create a new one if not.
              if (!sound._panner || sound._panner.pan) {
                setupPanner(sound, 'spatial');
              }
  
              if (typeof sound._panner.positionX !== 'undefined') {
                sound._panner.positionX.setValueAtTime(x, Howler.ctx.currentTime);
                sound._panner.positionY.setValueAtTime(y, Howler.ctx.currentTime);
                sound._panner.positionZ.setValueAtTime(z, Howler.ctx.currentTime);
              } else {
                sound._panner.setPosition(x, y, z);
              }
            }
  
            self._emit('pos', sound._id);
          } else {
            return sound._pos;
          }
        }
      }
  
      return self;
    };
  
    /**
     * Get/set the direction the audio source is pointing in the 3D cartesian coordinate
     * space. Depending on how direction the sound is, based on the `cone` attributes,
     * a sound pointing away from the listener can be quiet or silent.
     * @param  {Number} x  The x-orientation of the source.
     * @param  {Number} y  The y-orientation of the source.
     * @param  {Number} z  The z-orientation of the source.
     * @param  {Number} id (optional) The sound ID. If none is passed, all in group will be updated.
     * @return {Howl/Array}    Returns self or the current 3D spatial orientation: [x, y, z].
     */
    Howl.prototype.orientation = function(x, y, z, id) {
      var self = this;
  
      // Stop right here if not using Web Audio.
      if (!self._webAudio) {
        return self;
      }
  
      // If the sound hasn't loaded, add it to the load queue to change orientation when capable.
      if (self._state !== 'loaded') {
        self._queue.push({
          event: 'orientation',
          action: function() {
            self.orientation(x, y, z, id);
          }
        });
  
        return self;
      }
  
      // Set the defaults for optional 'y' & 'z'.
      y = (typeof y !== 'number') ? self._orientation[1] : y;
      z = (typeof z !== 'number') ? self._orientation[2] : z;
  
      // Setup the group's spatial orientation if no ID is passed.
      if (typeof id === 'undefined') {
        // Return the group's spatial orientation if no parameters are passed.
        if (typeof x === 'number') {
          self._orientation = [x, y, z];
        } else {
          return self._orientation;
        }
      }
  
      // Change the spatial orientation of one or all sounds in group.
      var ids = self._getSoundIds(id);
      for (var i=0; i<ids.length; i++) {
        // Get the sound.
        var sound = self._soundById(ids[i]);
  
        if (sound) {
          if (typeof x === 'number') {
            sound._orientation = [x, y, z];
  
            if (sound._node) {
              // Check if there is a panner setup and create a new one if not.
              if (!sound._panner) {
                // Make sure we have a position to setup the node with.
                if (!sound._pos) {
                  sound._pos = self._pos || [0, 0, -0.5];
                }
  
                setupPanner(sound, 'spatial');
              }
  
              if (typeof sound._panner.orientationX !== 'undefined') {
                sound._panner.orientationX.setValueAtTime(x, Howler.ctx.currentTime);
                sound._panner.orientationY.setValueAtTime(y, Howler.ctx.currentTime);
                sound._panner.orientationZ.setValueAtTime(z, Howler.ctx.currentTime);
              } else {
                sound._panner.setOrientation(x, y, z);
              }
            }
  
            self._emit('orientation', sound._id);
          } else {
            return sound._orientation;
          }
        }
      }
  
      return self;
    };
  
    /**
     * Get/set the panner node's attributes for a sound or group of sounds.
     * This method can optionall take 0, 1 or 2 arguments.
     *   pannerAttr() -> Returns the group's values.
     *   pannerAttr(id) -> Returns the sound id's values.
     *   pannerAttr(o) -> Set's the values of all sounds in this Howl group.
     *   pannerAttr(o, id) -> Set's the values of passed sound id.
     *
     *   Attributes:
     *     coneInnerAngle - (360 by default) A parameter for directional audio sources, this is an angle, in degrees,
     *                      inside of which there will be no volume reduction.
     *     coneOuterAngle - (360 by default) A parameter for directional audio sources, this is an angle, in degrees,
     *                      outside of which the volume will be reduced to a constant value of `coneOuterGain`.
     *     coneOuterGain - (0 by default) A parameter for directional audio sources, this is the gain outside of the
     *                     `coneOuterAngle`. It is a linear value in the range `[0, 1]`.
     *     distanceModel - ('inverse' by default) Determines algorithm used to reduce volume as audio moves away from
     *                     listener. Can be `linear`, `inverse` or `exponential.
     *     maxDistance - (10000 by default) The maximum distance between source and listener, after which the volume
     *                   will not be reduced any further.
     *     refDistance - (1 by default) A reference distance for reducing volume as source moves further from the listener.
     *                   This is simply a variable of the distance model and has a different effect depending on which model
     *                   is used and the scale of your coordinates. Generally, volume will be equal to 1 at this distance.
     *     rolloffFactor - (1 by default) How quickly the volume reduces as source moves from listener. This is simply a
     *                     variable of the distance model and can be in the range of `[0, 1]` with `linear` and `[0, ∞]`
     *                     with `inverse` and `exponential`.
     *     panningModel - ('HRTF' by default) Determines which spatialization algorithm is used to position audio.
     *                     Can be `HRTF` or `equalpower`.
     *
     * @return {Howl/Object} Returns self or current panner attributes.
     */
    Howl.prototype.pannerAttr = function() {
      var self = this;
      var args = arguments;
      var o, id, sound;
  
      // Stop right here if not using Web Audio.
      if (!self._webAudio) {
        return self;
      }
  
      // Determine the values based on arguments.
      if (args.length === 0) {
        // Return the group's panner attribute values.
        return self._pannerAttr;
      } else if (args.length === 1) {
        if (typeof args[0] === 'object') {
          o = args[0];
  
          // Set the grou's panner attribute values.
          if (typeof id === 'undefined') {
            if (!o.pannerAttr) {
              o.pannerAttr = {
                coneInnerAngle: o.coneInnerAngle,
                coneOuterAngle: o.coneOuterAngle,
                coneOuterGain: o.coneOuterGain,
                distanceModel: o.distanceModel,
                maxDistance: o.maxDistance,
                refDistance: o.refDistance,
                rolloffFactor: o.rolloffFactor,
                panningModel: o.panningModel
              };
            }
  
            self._pannerAttr = {
              coneInnerAngle: typeof o.pannerAttr.coneInnerAngle !== 'undefined' ? o.pannerAttr.coneInnerAngle : self._coneInnerAngle,
              coneOuterAngle: typeof o.pannerAttr.coneOuterAngle !== 'undefined' ? o.pannerAttr.coneOuterAngle : self._coneOuterAngle,
              coneOuterGain: typeof o.pannerAttr.coneOuterGain !== 'undefined' ? o.pannerAttr.coneOuterGain : self._coneOuterGain,
              distanceModel: typeof o.pannerAttr.distanceModel !== 'undefined' ? o.pannerAttr.distanceModel : self._distanceModel,
              maxDistance: typeof o.pannerAttr.maxDistance !== 'undefined' ? o.pannerAttr.maxDistance : self._maxDistance,
              refDistance: typeof o.pannerAttr.refDistance !== 'undefined' ? o.pannerAttr.refDistance : self._refDistance,
              rolloffFactor: typeof o.pannerAttr.rolloffFactor !== 'undefined' ? o.pannerAttr.rolloffFactor : self._rolloffFactor,
              panningModel: typeof o.pannerAttr.panningModel !== 'undefined' ? o.pannerAttr.panningModel : self._panningModel
            };
          }
        } else {
          // Return this sound's panner attribute values.
          sound = self._soundById(parseInt(args[0], 10));
          return sound ? sound._pannerAttr : self._pannerAttr;
        }
      } else if (args.length === 2) {
        o = args[0];
        id = parseInt(args[1], 10);
      }
  
      // Update the values of the specified sounds.
      var ids = self._getSoundIds(id);
      for (var i=0; i<ids.length; i++) {
        sound = self._soundById(ids[i]);
  
        if (sound) {
          // Merge the new values into the sound.
          var pa = sound._pannerAttr;
          pa = {
            coneInnerAngle: typeof o.coneInnerAngle !== 'undefined' ? o.coneInnerAngle : pa.coneInnerAngle,
            coneOuterAngle: typeof o.coneOuterAngle !== 'undefined' ? o.coneOuterAngle : pa.coneOuterAngle,
            coneOuterGain: typeof o.coneOuterGain !== 'undefined' ? o.coneOuterGain : pa.coneOuterGain,
            distanceModel: typeof o.distanceModel !== 'undefined' ? o.distanceModel : pa.distanceModel,
            maxDistance: typeof o.maxDistance !== 'undefined' ? o.maxDistance : pa.maxDistance,
            refDistance: typeof o.refDistance !== 'undefined' ? o.refDistance : pa.refDistance,
            rolloffFactor: typeof o.rolloffFactor !== 'undefined' ? o.rolloffFactor : pa.rolloffFactor,
            panningModel: typeof o.panningModel !== 'undefined' ? o.panningModel : pa.panningModel
          };
  
          // Update the panner values or create a new panner if none exists.
          var panner = sound._panner;
          if (panner) {
            panner.coneInnerAngle = pa.coneInnerAngle;
            panner.coneOuterAngle = pa.coneOuterAngle;
            panner.coneOuterGain = pa.coneOuterGain;
            panner.distanceModel = pa.distanceModel;
            panner.maxDistance = pa.maxDistance;
            panner.refDistance = pa.refDistance;
            panner.rolloffFactor = pa.rolloffFactor;
            panner.panningModel = pa.panningModel;
          } else {
            // Make sure we have a position to setup the node with.
            if (!sound._pos) {
              sound._pos = self._pos || [0, 0, -0.5];
            }
  
            // Create a new panner node.
            setupPanner(sound, 'spatial');
          }
        }
      }
  
      return self;
    };
  
    /** Single Sound Methods **/
    /***************************************************************************/
  
    /**
     * Add new properties to the core Sound init.
     * @param  {Function} _super Core Sound init method.
     * @return {Sound}
     */
    Sound.prototype.init = (function(_super) {
      return function() {
        var self = this;
        var parent = self._parent;
  
        // Setup user-defined default properties.
        self._orientation = parent._orientation;
        self._stereo = parent._stereo;
        self._pos = parent._pos;
        self._pannerAttr = parent._pannerAttr;
  
        // Complete initilization with howler.js core Sound's init function.
        _super.call(this);
  
        // If a stereo or position was specified, set it up.
        if (self._stereo) {
          parent.stereo(self._stereo);
        } else if (self._pos) {
          parent.pos(self._pos[0], self._pos[1], self._pos[2], self._id);
        }
      };
    })(Sound.prototype.init);
  
    /**
     * Override the Sound.reset method to clean up properties from the spatial plugin.
     * @param  {Function} _super Sound reset method.
     * @return {Sound}
     */
    Sound.prototype.reset = (function(_super) {
      return function() {
        var self = this;
        var parent = self._parent;
  
        // Reset all spatial plugin properties on this sound.
        self._orientation = parent._orientation;
        self._stereo = parent._stereo;
        self._pos = parent._pos;
        self._pannerAttr = parent._pannerAttr;
  
        // If a stereo or position was specified, set it up.
        if (self._stereo) {
          parent.stereo(self._stereo);
        } else if (self._pos) {
          parent.pos(self._pos[0], self._pos[1], self._pos[2], self._id);
        } else if (self._panner) {
          // Disconnect the panner.
          self._panner.disconnect(0);
          self._panner = undefined;
          parent._refreshBuffer(self);
        }
  
        // Complete resetting of the sound.
        return _super.call(this);
      };
    })(Sound.prototype.reset);
  
    /** Helper Methods **/
    /***************************************************************************/
  
    /**
     * Create a new panner node and save it on the sound.
     * @param  {Sound} sound Specific sound to setup panning on.
     * @param {String} type Type of panner to create: 'stereo' or 'spatial'.
     */
    var setupPanner = function(sound, type) {
      type = type || 'spatial';
  
      // Create the new panner node.
      if (type === 'spatial') {
        sound._panner = Howler.ctx.createPanner();
        sound._panner.coneInnerAngle = sound._pannerAttr.coneInnerAngle;
        sound._panner.coneOuterAngle = sound._pannerAttr.coneOuterAngle;
        sound._panner.coneOuterGain = sound._pannerAttr.coneOuterGain;
        sound._panner.distanceModel = sound._pannerAttr.distanceModel;
        sound._panner.maxDistance = sound._pannerAttr.maxDistance;
        sound._panner.refDistance = sound._pannerAttr.refDistance;
        sound._panner.rolloffFactor = sound._pannerAttr.rolloffFactor;
        sound._panner.panningModel = sound._pannerAttr.panningModel;
  
        if (typeof sound._panner.positionX !== 'undefined') {
          sound._panner.positionX.setValueAtTime(sound._pos[0], Howler.ctx.currentTime);
          sound._panner.positionY.setValueAtTime(sound._pos[1], Howler.ctx.currentTime);
          sound._panner.positionZ.setValueAtTime(sound._pos[2], Howler.ctx.currentTime);
        } else {
          sound._panner.setPosition(sound._pos[0], sound._pos[1], sound._pos[2]);
        }
  
        if (typeof sound._panner.orientationX !== 'undefined') {
          sound._panner.orientationX.setValueAtTime(sound._orientation[0], Howler.ctx.currentTime);
          sound._panner.orientationY.setValueAtTime(sound._orientation[1], Howler.ctx.currentTime);
          sound._panner.orientationZ.setValueAtTime(sound._orientation[2], Howler.ctx.currentTime);
        } else {
          sound._panner.setOrientation(sound._orientation[0], sound._orientation[1], sound._orientation[2]);
        }
      } else {
        sound._panner = Howler.ctx.createStereoPanner();
        sound._panner.pan.setValueAtTime(sound._stereo, Howler.ctx.currentTime);
      }
  
      sound._panner.connect(sound._node);
  
      // Update the connections.
      if (!sound._paused) {
        sound._parent.pause(sound._id, true).play(sound._id, true);
      }
    };
  })();
  