The soundtrack is just about 4.5 seconds ahead of the pyro. Not the reports from the pyro but the actual breaks. The sound was perfect for the NYE show.
For instance, at the very beginning of the show, the EWP turns on and that is when the in-park fan is supposed to go as well.
I am thinking the audio feed to the EWP barges was slightly delayed. The NYE show I manually synced the audio from a recording from the MK hub.