I tried putting all my background music files under Resources/music folder and despite the fact that the music file is recognized (audio description appears in the console), no sound is played. When I move that file to the parent /Resources folder, music is played.
I also did not forget to add this line of code in AppDelegate.cpp searchPath.push_back(resourceDirectory + "/music");
So I don’t understand what I’m doing wrong. The only solution seems to put all files in main Resources folder but what a mess then… 
EDIT: Ok apparently adding a search path for my musics doen’t work but I can still write the full path when playing the file
SimpleAudioEngine::sharedEngine()->preloadBackgroundMusic("music/bg_music.mp3"); SimpleAudioEngine::sharedEngine()->playBackgroundMusic("music/bg_music.mp3", true);