Good catch @josh.
I just tried @David_McNae’s mp3 file in Dropbox, and that appears to be working properly.
So I uploaded the file to dropbox’s public folder, and generated a link like this.
“Dropbox - Police Siren Sound Effect (1).mp3 - Simplify your life”
And I had to replace host name and url parameter to this to get the direct file download url.
“https://dl.dropboxusercontent.com/s/nz4q7ikaaim66gz/Police%20Siren%20Sound%20Effect%20(1).mp3?dl=1”
That works beautifully. 