I'm Alex, with the Shopify team!
Understood! This isn't a recommended customization, not so much for moral reasons but more due to usability and customer experience; autoplay tends to annoy customers, and interrupts their browsing experience.
That said, if this is something you'd like to introduce to your site, there's a few options I can recommend:
Hope that's helped! Please feel free to let me know, and you can always give us a call or start a live chat at any time. We're open 24/7 for your convenience and always happy to assist!
Alex | Shopify
I'm not sure why Alex has to refer you to shopify apps, there's an easy solution to how you can get music to autoplay on your homepage.
If you go into your index.liquid you can just add an iframe and set it's display to none.
<iframe src="youraudiofile.mp3" allow="autoplay" style="display:none" id="iframeAudio">
Upload the file to the CDN. Settings in the bottom right of the admin, Files, Upload, copy the url it gives you after upload and place it in the source. Since it had been so long since I posted this I just copied and pasted my code into my index.liquid on my developer store, uploaded an MP3 to my CDN, copied the link and pasted it into the source of my code and it's working. So there :P