Audio player not showing: Visibility is set to hidden

This is the first time I’m experiencing this issue and it really bugs me…

Maybe since a week ago, the audio player in my page (http://futari.perrylandia.in) isn’t showing. I’ve read several topics in this forum and they all say that the fix is adding the right <?php wp_head(); ?> / <?php wp_footer(); ?> tags in my theme; but they’re all here. Video player seems to work just fine but audio player is not.

Yes, I deactivated all my plugins.

For the meantime I have edited my wp-includes/media.php file and removed the visibility: “hidden” style, but I know that that isn’t a permanent solution (also, I don’t like to mess up with the files in wp-include).

Can anybody help me here? Thanks!