HTML audio tag volume

Theres no volume attribute supported by browsers so you must set the volume property in JavaScript

<audio autoplay id="myaudio">
  <source src="http://lel.com/link/to/stream.m3u">
</audio>

<script>
  var audio = document.getElementById("myaudio");
  audio.volume = 0.2;
</script>

See http://jsfiddle.net/sjmcpherso/6r1emoxq/