Reverberation describes the pattern of echoes and reflections that occur when a sound is heard in a space, for example, in a concert hall. The subtle echoes and reflections help the brain to perceive the size and shape of an acoustic space. Every space has different reverb characteristics.
Clap without reverb
Clap with reverb
The reverb unit can be used in a mix to create space, a sense of stereo width or a front to back perspective.
A reverb processor adds an artificial reverberant sound for a wide range of pre-chosen acoustic environments. Some common presets found on a reverb unit include room, hall and cathedral.
Reverbs offer numerous settings and parameters with the main one being the decay time - the time it takes for the reverb to die away. Other common parameters include choosing the size and brightness of the location/sound.
More advanced reverb units offer control over even more parameters, such as reflection density and pre-delay between the sound and the reverb that follows.
Adding reverb tends to push a sound to the back of a mix, making it seem more distant and behind other instruments. Many engineers use reverb to make a sound bigger and lusher. Lots of modern day recordings use a touch of reverb on vocals and other instruments to add excitement.
Common Reverb Controls
Algorithms - The algorithm control determines the preset reverb algorithms e.g. Hall, room, concert etc.
Size - The size control adjusts the artificial room size giving a different tonal characteristic.
Decay - The decay control determines how long the reverb lasts. Shorter decays give the impression of greater acoustic absorbency where as longer decays have the opposite effect.
Damp - The damp control determines if the higher frequency content is dampened. Dampening the high frequencies can help to free up mix room and promote a warmer sound.
Dry/Wet - The dry/wet control adjusts the balance between the unprocessed audio signal (dry) and the delay effect (wet).
Reverb is used to add aural space to an instrument or sound. The following tips provide a good starting point to begin experimenting with reverb:
- Short reverbs with a decay less than 500 milliseconds help fatten up an instrument. Long reverbs with a decay of more than 500 milliseconds will make an instrument float and push the sound back from the listener. Be careful not to over use reverb as it can make a sound muddy and too distant
- Reverb can smear the stereo placement of an instrument in the mix. To keep a specific stereo position of a sound, use a mono reverb panned to the same position as the dry (unprocessed) signal
- A bright, medium decayed reverb can make vocals sound excellent, helping them sit well with the rest of the mix. Beware not to add too much, as the sound will become sibilant and lost in the mix
- Adding EQ to the reverb signal can help create some sonic layering i.e. each instrument has its own ambient environment. The idea is to create individual sonic atmospheres that do not clash with each other:
- To brighten up a sound, add more high frequency content
- To help a sound blend into a mix, remove the high frequencies
- If an instrument sounds muddy, remove some low frequency content
- If the space is empty, add some low frequency content to help fill the space
- For long decays it is better to use brighter reverbs
- For short decays it is better to use duller reverbs
- Use long decayed reverbs on a couple of major elements in the track to help tie the sound together
- Try and time reverb units to the tempo of the track to make it more distinct. For example, on a snare hit the decay diminishes just before the next hit
- A very short amount of reverb on a sound can give it a sense of air
- Short amounts of reverb can give an aggressive, fatter sound on a snare drum