Applying a Reverb Filter to a collision event

I am working on a game where the player is able to fire a red cube prefab at a wall and when that happens, reverb is applied depending on the Reverb Filter attached to the wall. The end goal is that the walls are the sides of a large verticle tunnel and depending how deep they are, the reverb is adjusted accordingly. I can't use Reverb Zones because the player is not able to go down the vertical tunnel.

The wall is a primited 3D cube flattened out. The shooting and audio triggering element is working perfectly and I have attached a script to the prefab that allows me to add multiple impact sounds to it. I am using a collision event to detect when prefab hits the wall and then I trigger these sounds in 3D space using PlayOneShot. Here is the script attached to the Prefab:

Code (csharp):

1. usingUnityEngine;
2. usingSystem.Collections;
3.  
4. [RequireComponent(typeof(AudioSource))]
5. public class crateCol : MonoBehaviour {
6.  
7.     public AudioClip[] collisionClips;
8.     public float impactToVolRatio = .2F;
9.     public float minCollisionVolume = .1F;
10.     public int _nextClipIndex = 0;
11.  
12.     void OnCollisionEnter ( Collision coll ) {
13.         float volume = coll.relativeVelocity.magnitude * impactToVolRatio;
14.         volume = Mathf.Clamp ( volume, minCollisionVolume, 1f );
15.         GetComponent<AudioSource().PlayOneShot ( collisionClips[_nextClipIndex], volume );
16.         _nextClipIndex = ( _nextClipIndex + 1 ) % collisionClips.Length;
17.  
18.     }
19.  
20. }

I tried adding the Reverb Filter to the prefab but when the audio is triggered multiple times on a wall surface it resets the reverb such as demonstrated in this video:

If I attach the reverb filter to the wall, it requires an audio clip which is on the prefab. I need to grab the clip that is played on collision and send it to the reverb filter.
Is this the right way of doing it?

Any help much appreciated!