song1 = Resources.Load ("[song1filename]") as AudioClip;
song2 = Resources.Load ("[song2filename]") as AudioClip;
song3 = Resources.Load ("[song3filename]") as AudioClip;
song4 = Resources.Load ("[song4filename]") as AudioClip;

 function OnTriggerEnter (other : Collider) {
    {
  if (other.gameObject.tag == "Player");
  if (gameObject.tag == "Songbox1") {
  AudioClip song = Resources.Load("[song1filename]") as AudioClip
  source.clip = song;
  source.Play();

        }
    }
}

 function OnTriggerEnter (other : Collider) {
    {
  if (other.gameObject.tag == "Player");
  if (gameObject.tag == "Songbox2") {
  AudioClip song = Resources.Load("[song2filename]") as AudioClip
  source.clip = song;
  source.Play();

        }
    }
}
 function OnTriggerEnter (other : Collider) {
    {
  if (other.gameObject.tag == "Player");
  if (gameObject.tag == "Songbox3") {
  AudioClip song = Resources.Load("[song3filename]") as AudioClip
  source.clip = song;
  source.Play();

        }
    }
}
 function OnTriggerEnter (other : Collider) {
    {
  if (other.gameObject.tag == "Player");
  if (gameObject.tag == "Songbox4") {
  AudioClip song = Resources.Load("[song4filename]") as AudioClip
  source.clip = song;
  source.Play();

        }
    }
}
@script RequireComponent(AudioSource)