Introduction to Music Production 7 – Reverb
Reverb (Reverberation) is an effect that creates a sense of space and place in a song. It can help give a listener the perception of a location. It is the persistence of sound after a sound is produced. It is created when a sound or signal is reflected causing a large number of reflections to build up and then decay as the sound is absorbed by the surfaces of objects in the space. It is most noticeable when a sound source stops, but the reflections continue, decreasing in amplitude over time.
Pre Delay – The amount of time it takes for the first reflection to reach the listener.
Decay Time (Reverberation Time) – also known as RT60, it is the amount of time the reflections amplitude decrease by 60 dB.
Stereo – The stereo width of the reverberations.
Size – The size of the perceived room in which a sound is reverberating.
Wet/Dry – A mix between the purely dry and purely wet (reverbed) signal. This is a common feature of most effects.
High/Low Cut – Most reverbs contain filters (see my post on EQ) to assist in shaping the timbre of the reverberations.
There are three common types of reverb: Plate, Hall, and Spring.
Hall is the most common of the three, since it is reverb that is naturally occurring (or digitally reproduced) in a physical place.
Plate was one of the first types of artificial reverb used in recording. Initially, a steel plate under tension supplied by springs at the corners vibrated in accordance with a signal from a transducer and the vibration was sensed elsewhere on the place with contact microphones. “Put your ear up to any large metal item and tap on it and you will hear how steel plates were used to create reverb” (Sweetwater).
Spring was initially introduced from the Hammond Organ Company as an internal reverb effect. Spring reverbs are usually enclosed in a metal box, called the reverb pan, which is attached to the bottom of an amplifier. An audio signal is sent to one end of the spring (or multiple springs) b a transducer, creating waves that travel through the spring. At the other end of the spring, another transducer converts some of the motion of the spring into an electrical signal, which is added to a the dry sound. When a wave arrives at the end of the spring, part of the wave’s energy is reflected and stays in the spring. These reflections create the reverb characteristic sound (Sweetwater).
Volume, Reverb, and Panning are the three components of a concept called Spatialization. Spatialization is the concept of creating a sense of place in audio, giving the listener a more dramatic and lifelike listening experience.