MusicManager.cs

public class MusicPlayer : MonoBehaviour {
	static MusicPlayer instance = null;
	
	void Start () {
		if (instance != null) {
			Destroy (gameObject);
			print ("Duplicate music player self-destructing!");
		} else {
			instance = this;
			GameObject.DontDestroyOnLoad(gameObject);
		}
		
	}
}