I am assuming you are wanting to do this programmatically, which is why you are not using the built-in repeat option for the audio widget.
Have you tried subscribing to the events to listen for the end? Check out the Consuming Events example in the Audio Widget API documentation. I have not tried this but it looks like it may be a solution.
Specifically, this snippet:
var aw1 = AudioPlayerWidget.fromWidget('m1-test-audio1-container');
function onEnd(event) {
event.player.play();
}
// subscribe for events
aw1.events.bind('ended', onEnd);
aw1.events.bind('ended paused', function(event) { console.log(event.type); });
// unsubscribe
aw1.events.unbind('ended', onEnd);