Yes, it is possible to add sound to Issuu publications. The sound file must be placed online and must start playing as soon as the site is accessed, otherwise it won’t be possible for the Issuu reader to start the sound file. The link to the sound file can be inserted when the document is uploaded, but it is also possible to add the sound after publishing.
To add music to a particular publication:
1. Click on the drop down menu of that publication under 'Publisher Tools' you want to add music to, and then select "Edit".
2. Click on the "Add audio playback" button under 'Document Settings', and type in the link to the mp3 file you wish to add to your publication.
3. Click on "Save Changes" after adding your mp3 file, and you should be good to go.
NOTE: These are the specifications for the sound file to be uploaded:
The audio file should remain hosted online
The audio files should not be on a secure network, so the URL should start with http:// and not https://
The audio files should have an mp3 or m3u extension
The audio files should not have any start button, so it should start playing automatically as soon as you load the page