Custom Tank music doesn't loop

[pilot7893]

I set my Tank music in L4D to a mix of Andy Hunter's Come On, so I could have a regular version and a finale version. I then put snd_rebuildsoundcache in Console to prevent it cutting off at the default tank music length. However, once the file finishes playing in game, it doesn't loop. It just stops. What happened? I did something similar earlier on with other tank music, but there was just an awkward cut in between loops.