Reverb is the collection of reflected echoes that bounce of the floor, walls, ceiling and objects in a space such as a room. A large reverberant room (e.g. cathedral) has lots reflective surfaces and strong reflections and a small non-reverberent room (e.g. tent) has few reflective surfaces and weak reflections.

The time between the sound source and its first reflection is called pre-delay. Larger rooms have a longer pre-delay and smaller rooms have a shorter pre-delay.

Sound without reverb sounds un-natural and some recording engineers do not like too much reverb on a sound source as they like to be able to add it electronically after the recording has been made. A recording with lots of reverb is described as being 'wet' whereas a recording with little reverb is described as being 'dry'.

Reverb is measured in seconds. The reverb time for a typical living room is approx. 0.5s and this makes a living room a good recording space.