Music! Every universe has its own music - normally a singular tone at which is vibrates. This keeps each universe from collapsing into the others - a sound wall, if you will.

The wall here, is broken, but something is keeping us together, so there must not be a single note, but a harmonic chord made up of all the different sounds, Belly. I just have to understand what the chord is, find the right tone and send us all back.