For radio streaming, this is the code  embed i use for the html5 player:

<audio id="stream" style="width: 400px;" preload="none" controls="controls">

<source src="https://domainame.com/port/stream" type="audio/mpeg" /></audio>

For mp3 files, this the embed code:

<audio controls="controls">

  <source src="audiofilename.ogg" type="audio/ogg" />

  <source src="audiofilename.mp3" type="audio/mpeg" />

Your browser does not support the audio element.</audio>

The text editor adds the p tag at the ends, but it still works.

Posts App also comes with audio attach/insert option