How to play music on collision enter (audio source on player)

Hi everybody ! I want a music to start when the player hit a specific object. I’m using this script :

function OnCollisionEnter (collision : Collision) 

(whith an audio source on the object)

But everytime the player go away, the music is going lower and lower…

Can you help me ?

Adding Locksteps answer as an actual answer so this question can be closed.

The volume of a 3d sound depends on the distance of the source and the listener. You can mark a sound as 2d in the import settings to prevent this scaling effect.