What is reverb? If you’ve ever been in a large room, like a cathedral, you’ve heard naturally occurring reverb. Reverb is short for reverberation, which is a prolonging of a sound. Natural reverb occurs in rooms where the dry/original sound bounces off of surfaces in the room creating a cascade of reflections or echoes of the original that arrive at the listener at different times. The more times the sound bounces around, the more (and different) reflections are created as the energy dies out over time. The sound of the reverb is changed by bouncing off of different materials and surfaces with varying degrees of coarseness and absorption.