title: MIDI.js - Unable to change instruments
body: <p>I am trying to initialize MIDI.js with a glockenspiel instead of the default acoustic piano.   But I am getting no sounds</p>
  
  <p>I have glockenspiel-ogg.js and glockenspiel-mp3.js (downloaded from <a href="https://github.com/gleitz/midi-js-soundfonts" rel="noreferrer">https://github.com/gleitz/midi-js-soundfonts</a> )  in a directory called soundfont.</p>
  
  <p>I am running the following code on window.onload.  Where am I going wrong?</p>
  
  <pre><code>MIDI.loadPlugin({
  soundfontUrl: "soundfont/",
  instrument: "glockenspiel",
  callback: function() {
  MIDI.programChange(0, 10); 
  MIDI.noteOn(0, 35, 127, 0);
  }
  });
  </code></pre>