Android : How to make a proper relative path for the media plugin in phonegap?

I know there are already some discussions about this but I still can't make this work. My media plugin does work because when I work with a url-link it works , but this let's the sound play really slow.

I now have this as a relative path but it isn't working :

song = new Media("./android/assets/www/sound/twitch.mp3");