Reverb

The effect of reverb can be an extremely handy way of adding that extra bit of life and depth to a sound or mix, as well as helping to define the space that the sound is perceived to be in. Reverb effects can be a little complicated to get your head around, so to help you out we have prepared the following guide to help you to firstly understand what reverb is in the real-world, and also how this translates to a typical reverb plug-in or effect unit.

Reverb is a type of time-based effect which is used to add a sense of room acoustics, ambience or space to a sound. Reverb effects units typically attempt to simulate the reverberation typically experienced in a real-world situation, such as a hall, room or outdoor space, which make the original sound persist and gradually fade away. Reverberation in the real world is made up of a series of reflections, caused by the original sound bouncing off the surrounding surfaces, which enables us to tell what sort of surfaces are present (eg: hard or soft), as well as the general size of the space.

There are two main parts to reverberation in the real world. The first part is the early reflections which are the initial reflections heard before the reverb itself has propagated, and are generally fewer in number and less dense than the reverb tail itself. The second part consists of the reverb tail, which is a denser, more closely spaced set of reflections that die out over time.

Reverb differs from a delay or echo type of effect, in that it is more of a smooth decaying of the original sound, rather than distinct repetitions of the original. Different types of reverb effects also exist, including spring and plate type reverbs, which provide a reverb with different sonic characteristics than those that are more of a simulation of real world reverb. Another type of reverb that is used is convolution reverb which uses impulse responses to accurately recreate real acoustic spaces, such as studio recording rooms or performance venues, although convolution reverbs tend to use more CPU power than other types.

The controls or parameters on a typical reverb plug-ins and effects units are:

• Reverb Time (RT60): The Reverb Time or RT60, is the time it takes for the sound of the reverb to die down by sixty decibels (60dB).
• Early Reflections: The early reflections control typically allows you adjust the level of the the first reflections heard between the original sound and the onset of a reverb. Reverb simulation of a normal small room can sometimes be easily achieved by using only early reflections, without the reverb tail, although this depends on the particular reverb plug-in or effects unit used.
• Pre-delay: The pre-delay is the delay (in milliseconds) between the original sound and when the reverb starts, which is an acoustic anomaly present in the real world. The pre-delay in the effect sense also helps to add clarity to the sound by removing the start of the reverb from the direct sound.
• Density: A higher density setting produces more reflections, closer together which can provide a smoother sound, typically at the expense of CPU usage (when using a plug-in). A lower density setting produces less reflections, spaced further apart.
• Damping: The damping parameter adjusts the reverb time of the higher frequencies of the spectrum, with higher settings producing the sound of a hard-surfaced room, with lower settings providing a slightly warmer sound, simulating a more soft-surfaced room.
• Dry/Wet or Mix Control: This parameter allows you to adjust the mix level between the original sound and the reverb. When using a reverb plug-in or effects unit on a auxiliary return channel it is typical to set the mix control to 100% wet.

There is no hard and fast rule as to what type of reverb you should use, or how much you should apply. It is more a case of experimenting to find the effect that you are after, whether it be subtle reverb to help define the space of a sound, or a very wet reverb that provides more of an actual effect than a simple enhancement. Feel free to play around and see what sort of sounds you can come up with.