Vizualized echo (sound rays)

This should get you started. Note all of the vectors generated are length 1, so you can easily multiply them by whatever "speed" you want your rays to spread.

You'll probably need to instantiate some objects with colliders and trail renderers to get the effect of the video.

 public int RayCount;
 List<Vector3> directions = new List<Vector3> ();

 private void OnValidate () {
     directions = new List<Vector3> ();

     float step = (Mathf.PI * 2) / (float) RayCount;
     for (int i = 0; i < RayCount; i++) {
         directions.Add (new Vector3 (Mathf.Cos (i * step), Mathf.Sin (i * step), 0));
     }
 }

 private void Update () {
     foreach (Vector3 direction in directions) {
         Debug.DrawRay (transform.position, direction, Color.red);
     }
 }