As a crazy thought entered my mind: a story where at some points, you HAVE to listen. In short, the story would have a link to Youtube where you cannot get part of the story without following the audio recording. It would be used sparingly but mostly to say "let's magnify the drama/comedy/tragedy/everything!"
Please don't.
Here's the problem. You never
ever make the bells and whistles (such as sound) mandatory for understanding a fanfiction. Sure, you can have illustrations if you want, but ultimately, you should never have a story rely on alternative media. Why?
Because what happens if your readers can't access that recording?
Think about it. There are so many things that could prevent a recording from being opened and heard. Your reader could be in a situation where they
can't listen to a recording at the moment. (Libraries, school, in public, you name it.) Your reader could be offline. Your reader could have shoddy internet and would need to wait for minutes just to get the recording. Your video could be taken down at any moment for any of a variety of reasons on YouTube's part (or the part of whoever's hosting the file). YouTube (or the host) could go down while Serebii stays up. There's an entire list to go through, and all of those possibilities are more likely than one would think. (I know I can't listen to recordings after midnight, when I'm most active. I go through headphones like nobody's business too, so no, I can't just get a pair of headphones and listen whenever I want.) If you make a recording
mandatory, then your audience could end up missing part of your story because they just can't access that part.
That's one of two reasons why I thought the whole "link to background music in my fic" fad was incredibly silly, by the way. The other being the music choices the authors would put up were questionable, if you know what I mean. Seriously, if you link me to Linkin Park because you think it fits your scene, I judge you a little.
But anyway, yeah. You should never
ever make a video or audio bell or whistle
mandatory for enjoying your fic. You can make it optional (which would be perfectly cool and a fun idea), but if we can't get your story without having to sit through an audio recording that we may or may not be able to download anyway, that's just not a good thing. You don't want to frustrate your readers, but that's exactly what you could end up doing if you put part of your story beyond their reach because you want to force a perk on them (at the risk of putting it overly bluntly).