Reverb
From DNBWiki
Reverb is short for reverberation, but is generally only referred to in its abbrieviated form. Reverb is defined as the type of echo where the individual echoes are neither distinct nor separate, as is experienced in a small to medium-sized room, for example. Artificial reverb is created mainly by two methods; DSP reverb and convolution reverb. Reverb can also be created in the real world and recorded.
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[edit] DSP Reverb
DSP reverbs effectively use a great number of very short echos, which the human ear is unable to separately distinguish, so that they blend into a reverb tail. This is usually combined with a filter or EQ applied to the tail, and perhaps other features or parameters, for a more realistic final result. Usually the EQ response, reverb time and so on can be adjusted by the engineer.
Commonly used DSP reverb units include:
- Alesis Quadraverb (hardware)
- Lexicon MPX100, a hardware multieffects processor which includes a widely used reverb setting.
- TC Works Native Reverb (software)
[edit] Convolution Reverb
Convolution reverbs are a special kind of DSP reverb processors, and work in a completely different way from the majority of DSP reverb devices. Effectively, real spaces are "sampled" by playing a given sine-tone and recording the results. This is known as an "impulse". The convolution processor then applies the characteristics of the impulse to whatever material you feed through it. With convolution reverbs, the EQ response and reverb time are inherent properties of the impulse response, so often cannot be directly edited, although some hybrid plugins do manage to allow this type of control.
One commonly used convolution reverb unit is the Waves IR software plugin.
Emusician article on convolution reverb and its uses.
[edit] Metal reverb
Reverb can also be created by the use of metal in a variety of methods, mostly employed in the early days of music production, when electronic gear was not in wide use, mainly due to it not being invented yet.
- Plate reverb involves playing the signal through a loudspeaker which is connected to or which touches a a large plate of metal. The metal sheet reverberates, creating an echo-type sound, which is recorded by a microphone, also connected to the plate. This method of creating reverb was in common use in Jamaican dub studios. A major disadvantage of plate reverb units were their size (up to 6ft square or larger) and cost. The reverb they created did not sound realistic, as would be experienced in a normal environment, but was generally very pleasing to the ear in a musical sense.
- Spring reverb works in a similar fashion to plate reverb, but uses a smaller metal spring to produce the reverberation. The reverb produced by spring reverbs was often not as harmonically rich as that of plate reverbs, but the smaller size and thus cheaper cost made them a more attractive solution to most engineers on a budget. Spring reverb units were often incorporated into high-end guitar amplifiers, such as the Fender Twin.
- Note that although the echoes produced by plate and spring reverb units could not be described as realistic, they are both very pleasing to the ear. For this reason, many modern electronic units offer plate and spring simulation settings.
[edit] "Real-world" reverb and "worldizing"
Another method of creating reverb exists, which involves playing the audio from a source in an acoustic chamber, and recording the sound at another point in the room, thus picking up the echo. This can then be mixed with the dry recorded signal to create the echo on record. This method is perhaps used most often in the film industry, where it is termed "worldizing". Here the acoustic chamber would be "tuned" to match the echoes present in the environment depicted onscreen, since the audio in films is usually recorded on a sound stage or in an anechoic booth in a studio.
This method has no such term in music production, perhaps due to its rare use. The budgets of bedroom producers and all but the most expensive and lavish of recording studios do not permit the construction and maintenance of an acoustic chamber simply for the use of its reverb. Of course, lower budget, "ghetto" set ups have been used, with varying success. One example would be producer Martin Hannett setting up the band Joy Division's drum kit in the studio's ceramic-tiled toilet, to capture its unique reverb on the Unknown Pleasures album.
