This post has a featured image set and the [audio] shortcode inserted at the top of the content like this:

[audio src="http://yoursite.com/wp-content/uploads/xx/xx/sample-audio.mp3"][/audio]

Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam.

Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam.

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