Are your windows braced? Have you adjusted the volume on your device? Did you remember to borrow your grandparent’s hearing aids? Then you might just be prepared for the vocal earthquake that was the live debut of Christina Aguilera and Demi Lovato’s new duet “Fall in Line” at the Billboard Music Awards. Dressed like extras in The Matrix, the two performed in front of an eclipse in an attempt to eclipse each other in the cross-generational Disney Channel diva-off of our time. Just when you think your ear drums have had enough, one singer raises the decibel level to out-holler the other.