From 1d59e3612a39061c9a44c1547bc6fd7ba67c13b0 Mon Sep 17 00:00:00 2001
From: Lee Stemkoski <stemkoski@gmail.com>
Date: Thu, 7 Apr 2022 19:42:04 -0400
Subject: [PATCH] added Howler.js for audio playback

---
 js/howler.js | 3242 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 3242 insertions(+)
 create mode 100644 js/howler.js

diff --git a/js/howler.js b/js/howler.js
new file mode 100644
index 0000000..a2758c7
--- /dev/null
+++ b/js/howler.js
@@ -0,0 +1,3242 @@
+/*!
+ *  howler.js v2.2.3
+ *  howlerjs.com
+ *
+ *  (c) 2013-2020, 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;
+    },
+
+    /**
+     * Handle stopping all sounds globally.
+     */
+    stop: function() {
+      var self = this || Howler;
+
+      // Loop through all Howls and stop them.
+      for (var i=0; i<self._howls.length; i++) {
+        self._howls[i].stop();
+      }
+
+      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$/, '');
+
+      // Opera version <33 has mixed MP3 support, so we need to check for and block it.
+      var ua = self._navigator ? self._navigator.userAgent : '';
+      var checkOpera = ua.match(/OPR\/([0-6].)/g);
+      var isOldOpera = (checkOpera && parseInt(checkOpera[0].split('/')[1], 10) < 33);
+      var checkSafari = ua.indexOf('Safari') !== -1 && ua.indexOf('Chrome') === -1;
+      var safariVersion = ua.match(/Version\/(.*?) /);
+      var isOldSafari = (checkSafari && safariVersion && parseInt(safariVersion[1], 10) < 15);
+
+      self._codecs = {
+        mp3: !!(!isOldOpera && (mpegTest || audioTest.canPlayType('audio/mp3;').replace(/^no$/, ''))),
+        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$/, ''),
+        wav: !!(audioTest.canPlayType('audio/wav; codecs="1"') || audioTest.canPlayType('audio/wav')).replace(/^no$/, ''),
+        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$/, ''),
+        m4b: !!(audioTest.canPlayType('audio/x-m4b;') || audioTest.canPlayType('audio/m4b;') || audioTest.canPlayType('audio/aac;')).replace(/^no$/, ''),
+        mp4: !!(audioTest.canPlayType('audio/x-mp4;') || audioTest.canPlayType('audio/mp4;') || audioTest.canPlayType('audio/aac;')).replace(/^no$/, ''),
+        weba: !!(!isOldSafari && audioTest.canPlayType('audio/webm; codecs="vorbis"').replace(/^no$/, '')),
+        webm: !!(!isOldSafari && 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.
+        while (self._html5AudioPool.length < self.html5PoolSize) {
+          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;
+            break;
+          }
+        }
+
+        // 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);
+          document.removeEventListener('keydown', 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);
+      document.addEventListener('keydown', 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';
+
+        // Handle updating the state of the audio context after suspending.
+        var handleSuspension = function() {
+          self.state = 'suspended';
+
+          if (self._resumeAfterSuspend) {
+            delete self._resumeAfterSuspend;
+            self._autoResume();
+          }
+        };
+
+        // Either the state gets suspended or it is interrupted.
+        // Either way, we need to update the state to suspended.
+        self.ctx.suspend().then(handleSuspension, handleSuspension);
+      }, 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.ctx.state !== 'interrupted' && self._suspendTimer) {
+        clearTimeout(self._suspendTimer);
+        self._suspendTimer = null;
+      } else if (self.state === 'suspended' || self.state === 'running' && self.ctx.state === 'interrupted') {
+        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 === 'metadata') ? 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._xhr = {
+        method: o.xhr && o.xhr.method ? o.xhr.method : 'GET',
+        headers: o.xhr && o.xhr.headers ? o.xhr.headers : null,
+        withCredentials: o.xhr && o.xhr.withCredentials ? o.xhr.withCredentials : 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._preload !== 'none') {
+        self.load();
+      }
+
+      return self;
+    },
+
+    /**
+     * 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;
+      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 = !!(sound._loop || self._sprite[sprite][2]);
+      };
+
+      // 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' && Howler.ctx.state !== 'interrupted') {
+          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);
+                  } else {
+                    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);
+            }
+
+            // 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;
+          self._state = 'loading';
+
+          var listener = function() {
+            self._state = 'loaded';
+            
+            // 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 passed, 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 = Math.min(Math.max(0, parseFloat(from)), 1);
+      to = Math.min(Math.max(0, parseFloat(to)), 1);
+      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;
+
+        // Round to within 2 decimal points.
+        vol = Math.round(vol * 100) / 100;
+
+        // Make sure the volume is in the right bounds.
+        if (diff < 0) {
+          vol = Math.max(to, vol);
+        } else {
+          vol = Math.min(to, vol);
+        }
+
+        // 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;
+
+              // If playing, restart playback to ensure looping updates.
+              if (self.playing(ids[i])) {
+                self.pause(ids[i], true);
+                self.play(ids[i], true);
+              }
+            }
+          }
+        }
+      }
+
+      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.
+        if (self._sounds.length) {
+          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 0;
+      }
+
+      // If the sound hasn't loaded, add it to the load queue to seek when capable.
+      if (typeof seek === 'number' && (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() {
+            // Restart the playback if the sound was playing.
+            if (playing) {
+              self.play(id, true);
+            }
+
+            self._emit('seek', id);
+          };
+
+          // 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);
+          sounds[i]._node.removeEventListener('ended', sounds[i]._endFn, 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 if (!Howler.noAudio) {
+        // 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);
+
+        // Listen for the 'ended' event on the sound to account for edge-case where
+        // a finite sound has a duration of Infinity.
+        self._endFn = self._endListener.bind(self);
+        self._node.addEventListener('ended', self._endFn, false);
+
+        // Setup the new audio node.
+        self._node.src = parent._src;
+        self._node.preload = parent._preload === true ? 'auto' : parent._preload;
+        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);
+    },
+
+    /**
+     * HTML5 Audio ended listener callback.
+     */
+    _endListener: function() {
+      var self = this;
+      var parent = self._parent;
+
+      // Only handle the `ended`` event if the duration is Infinity.
+      if (parent._duration === Infinity) {
+        // Update the parent duration to match the real audio duration.
+        // Round up the duration to account for the lower precision in HTML5 Audio.
+        parent._duration = Math.ceil(self._node.duration * 10) / 10;
+
+        // Update the sprite that corresponds to the real duration.
+        if (parent._sprite.__default[1] === Infinity) {
+          parent._sprite.__default[1] = parent._duration * 1000;
+        }
+
+        // Run the regular ended method.
+        parent._ended(self);
+      }
+
+      // Clear the event listener since the duration is now correct.
+      self._node.removeEventListener('ended', self._endFn, 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(self._xhr.method, url, true);
+      xhr.withCredentials = self._xhr.withCredentials;
+      xhr.responseType = 'arraybuffer';
+
+      // Apply any custom headers to the request.
+      if (self._xhr.headers) {
+        Object.keys(self._xhr.headers).forEach(function(key) {
+          xhr.setRequestHeader(key, self._xhr.headers[key]);
+        });
+      }
+
+      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 && !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 : Howler._volume, 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;
+  }
+
+  // Add to global in Node.js (for testing, etc).
+  if (typeof global !== 'undefined') {
+    global.HowlerGlobal = HowlerGlobal;
+    global.Howler = Howler;
+    global.Howl = Howl;
+    global.Sound = Sound;
+  } else if (typeof window !== 'undefined') {  // Define globally in case AMD is not available or unused.
+    window.HowlerGlobal = HowlerGlobal;
+    window.Howler = Howler;
+    window.Howl = Howl;
+    window.Sound = Sound;
+  }
+})();
+
+
+/*!
+ *  Spatial Plugin - Adds support for stereo and 3D audio where Web Audio is supported.
+ *  
+ *  howler.js v2.2.3
+ *  howlerjs.com
+ *
+ *  (c) 2013-2020, 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(xUp, Howler.ctx.currentTime, 0.1);
+        self.ctx.listener.upY.setTargetAtTime(yUp, Howler.ctx.currentTime, 0.1);
+        self.ctx.listener.upZ.setTargetAtTime(zUp, 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);
+    }
+  };
+})();