Since hassbian is accessible from the web, I recon there is a webserver in there somewhere. I need to store some static audio files that I would like to play. I tried storing them in /config/www/ and chmod -R 755 /config/ but I get a 404 when I try visiting
create a folder called www in your install. copy your PDF in there, and you’ll be able to access it from myip:8123/local/1.pdf
For your audio file, check the bitrate. I had an issue with a file that had very low bitrate (32kbps). After changing it to 192kbps it worked