Cannot play audio in IE using mediaelement

Since media_recorder is player agnostic, I'd prefer to have this taken care of in the mediaelement module. You can also add this to a custom module, if you have browscap module installed:

/**
 * Implements hook_theme_registry_alter().
 * Adds a custom theme function for mediaelement audio.
 */
function MODULE_theme_registry_alter(&$theme_registry) {
  $theme_registry['mediaelement_audio']['theme path'] = drupal_get_path('module', 'MODULE');
  $theme_registry['mediaelement_audio']['function'] = 'MODULE_theme_mediaelement_audio';
}

/**
 * Fixes issue where mediaelement only displays download link for wav files in IE.
 * @see MODULE_theme_registry_alter().
 */
function MODULE_theme_mediaelement_audio(&$variables) {
  $browser = browscap_get_browser();
  $mimetype = file_get_mimetype($variables['attributes']['src']);

  // Output embed if this is IE.
  if ($browser['browser'] == 'IE' && $mimetype == 'audio/x-wav') {
    $output = '<embed type="audio/x-wav" width="100%" height="30" autostart="false" src="' . $variables['attributes']['src'] . '" />';
  }
  
  // Otherwise output HTML5 audio.
  else {
    $output = '<div class="mediaelement-audio">';
    $output .= '<audio ' . drupal_attributes($variables['attributes']) . ' ></audio>';
    if ($variables['settings']['download_link']) {
      $output .= '<div class="mediaelement-download-link"><a href="' . $variables['attributes']['src'] . '">' . filter_xss_admin($variables['settings']['download_text']) . '</a></div>';
    }
    $output .= '</div>';
  }

  return $output;
}