Yeah that's happened to me twice on IJ, both times when a whole lot was going on at once. Thought the speakers were going to blow, so I shut down the machine, waited, and rebooted, and all seemed good again. There are a couple other instances I've also had in the game that aren't as drastic as you experienced, but where a call out blasts way over usual volume, then goes back to normal shortly after. I assume it's a glitch?