_includes/extensions/soundcloud.html

<iframe class="extensions extensions--audio" width="100%" height="166"
  src="https://w.soundcloud.com/player/?url=https%3A//api.soundcloud.com/tracks/{{ include.id }}&color=%23ff5500&auto_play=false&hide_related=false&show_comments=true&show_user=true&show_reposts=false&show_teaser=true"
  scrolling="no" frameborder="no" allow="autoplay">
</iframe>