Problem Detecting 2D Collisions

The idea is that when a gameobject enters an empty gameobject's box collider, it will play a sound. However I am struggling to even detect collisions between the two objects!

Here is the setup of the empty game object:

And here is the gameobject which is colliding with it:

This is the code I am using for detecting collisions:

 using UnityEngine;
 using System.Collections;
 
 [RequireComponent(typeof(AudioSource))]
 public class playEricSound : MonoBehaviour {
 
     public AudioClip eric;
 
     void OnCollisionEnter2D (Collision2D collide) {
         print ("Collide");
         audio.PlayOneShot(eric);
     
     }
 }

Thanks for your help! If you need anything else, just ask!