Reverberation, also known as reverb, occurs when a sound is reflected. Reverb time is the time it takes for an impulse to decay in a specific space. In acoustic spaces, there are many reflections that hit the receiver each time they reach the surface. At some point, the absorption of the surface causes them to decay. It’s worth mentioning that the reflectivity of a space depends on the level of absorbency of the materials used. Also, some spaces are more reflective than others.
Diffraction is a phenomenon that occurs in large empty spaces with hard smooth walls. When this happens, the number of reverb increases, whereas when something interferes with the sound, some frequencies will go around it and get absorbed. As a result, the diffraction phenomenon arises, and the reverb time decreases. In audio production, reverb effects are obvious, and they are an essential part of every mix. Reverb effects are capable of enhancing songs since they add warmth, depth, and space.
Software and hardware reverb include basic parameters, such as type, room size, pre-delay, reverb time, damping, and mix. The type feature determines the mimicked type of space, as well as the device and/or the digital process. The room size is capable of adjusting the size of the virtual room and, as mentioned before, is determined by the type parameter. Pre-delay mimics the time it takes for the first reflection to return to the source after it has been spread. The reverb time, also known as tail, determines the time it takes for an impulse to lose energy in a virtual space. Damping is the absorption of high frequencies in the reverb. Finally, the mix, dry and wet, determines the balance between processed and dry signals.
There are several reverb types, including stereo pair, spring, sampling, chamber, plate, and digital emulators.
Stereo pair is achieved by mixing the output of a stereo pair in a room. This technique can accurately recreate the subtleties of a real room. Yet, when the room recording is not sympathetic to the overall mix, this method can turn into a limiting technique.
Spring reverb is an electromechanical device that uses transducers and steel springs to create replicas of the input. Sampling, also known as convolution, is an advanced reverb device that is capable of analyzing the response of a room. This analysis captures several qualities regarding the time and frequency domain of the response.
Chamber reverb involves an enclosed space with several mics that vary in size and shape, whereas digital chamber reverbs typically mimic small spaces with a short reverb tail. Plate reverb is a man-made device that works on one dimension and uses an electromechanical transducer to induce vibration. It also includes a sheet metal surface and a dampening mechanism to adjust decay time.
Digital reverbs, also known as algorithmic reverbs, are frequently used in modern studios. These devices mimic both natural and mechanical aspects of reverbs. Also, they are easy to manage and provide a lot of control.