Change Pitch on Collision

This is a very brief script that is supposed to do a very simple thing. What's wrong with it?

 using UnityEngine;
 using System.Collections;
 
 
 public class SoundManager : MonoBehaviour 
 {
     public AudioSource Backgroundmusic;      
 
     void OnCollisionEnter(Collider other) {
 
         if (other.tag == "Player") {
 
             Backgroundmusic.pitch = 0.4f;
         }
     }
 }