It wasn't shut down in that sense. A very informative MW staff member (he knows who he is! If he reads this, thank you ) explained to me that the LED green lantern logos on the front of the individual carts is doubled up on the switch which also controls the audio effects.
When the Lantern logo on a cart isn't working properly, it HAS to be turned off, because of strict DC requirements that the Green Lantern logo must be displayed properly at all times.
So since the LED lights on a couple of the carts recently were playing up, they had to be turned off, consequently the audio went with it.
Thankfully the good ol' Movieworld mechanics decided to finally tackle the problem today and fixed all the LED lights on the carts, thus now they can all be turned on normally again