Corona SDK Pro Tip of the Day #30
User's own background music

Allow users to listen to their own background music (apps that play music even when hidden). That currently works on iOS only.

To do so make sure you have "Music off" button in your app or game. Then paste this code at the very top of your main.lua.

require('audio')  
if audio.supportsSessionProperty then  
    audio.setSessionProperty(audio.MixMode, audio.AmbientMixMode)
end  

If you don't put it at the top and something else accesses audio before calling audio.setSessionProperty(), it will not work the correct way.

Instead, it will silence user's background music when your app is launched, but it will let it play if your app resumes from suspend. Therefore keeping it at the top of main.lua is very important.

Indie Game Developer