Autoplay is toggled by adding autoplay="True" to the html referencing the audiofile. It would look something like:
<audio src="http://www.filelocation.com/sound.mp3" autoplay="true">
You could add styling to your CSS in the fashion of:
<style>
audio {
display: none;
}
Worth mentioning that web browsers disable autoplay by default, though. So you'd have to go into whatever browser you're using to be able to have it autoplay when you visit your profile. The same applies to everyone else visiting your page. It can be coded to autoplay, but the majority of users will never hear the song unless they have the option to start it when they arrive.