The word ‘reverberation’ - or ‘reverb’ - conveys the idea of sound bouncing around in an enclosed space. Unless they’ve been acoustically treated (as a vocal booth in a recording studio would be), most rooms have a natural reverb.
Reverb plugins are designed to reproduce the ambience of an imaginary room or space. Alternatively, they can emulate older artificial technologies such as plate, spring and chamber reverbs. These are considered to have musically useful characteristics, and so are now emulated in plugin form.
On a basic level, reverb plugins work by generating a lot of closely spaced but random echoes to simulate reflected sound from a number of irregularly shaped objects. The end result is that each reflection is no longer heard in isolation but as part of a general ambience.
Because of the large number of calculations involved in creating a realistic sounding reverb, high quality reverb plug-ins tend to be pretty system intensive. Some are based on a technique called convolution; they’re rather CPU-hungry, but capable of breathtaking results.
Like most plugin effects, reverb should be used in moderation. In fact, reverb is often used in such small amounts that it's only noticeable when temporarily removed from the mix.
Now that we've covered the basics, let's take a look at 10 VST plugins that we reckon could well be the best available.