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How did the legendary engineers of the past use it? 



At The Recording Session Vault, it is an important component of our mission to promote an understanding through education about how the great music of the past was created. While part of my mission is to write biographies of the people behind the music, feature articles about the great studios, and to examine the technologies and to spotlight the companies that created them that have been so crucial to the development of popular music, it is also important to understand how the process of creating music actually worked, as well. With this educational series, we will explore the following topics: how the process of recording worked and how and why the technologies that were so important to that process were utilized. Plus, we will also discuss the products that engineers used to record the great popular music that we have come to love and to cherish. Without further ado, the first series of articles will focus on the types of processors that were used to record, mix and master the great music of the past. There are three types of processors: spectral processors (equalization units); timing processors (reverb and delay units) and amplitude (or dynamics) processors (compressors, gates and limiters). This article will discuss reverb units. Reverb units have had such a tremendous impact on the way in which the great popular music of the past was mixed and therefore presented to listeners, but in today’s world of professional music, they have almost all but disappeared despite their importance. Most of the reverb units that are in use today are software plugin emulations of the legendary digital units of the 1980s and 1990s. But, what is reverb, what were the fabulous technologies of the past and how were these units used by the legendary recording studio engineers of the past?

What is a reverb?


If you have ever wondered what makes a vocal shimmer, drums sound like thunder or guitars truly sound larger than life through your speakers, wonder no more—it’s reverb. A reverb is a timing processor. To put it simply, by changing the timing of a source an engineer can make a source sound larger, more distant or even give it a sheen or a shimmering quality that can be achieved with no other type of processor. The first reverb units were not actually rack-mount units at all. In fact, the first reverb units were either mechanical or were simply built into the studio facility itself as chambers. When you first turn on a digital reverb unit, or use a software plug-in that emulates a reverb unit, you will often notice the following: plates, halls, chambers, rooms and delays. There are other settings that you may notice such as ambience, chorus, tremolo, flange or even non-linear. The very first reverbs were echo chambers that were built into recording studio facilities as dedicated rooms. The first echo chamber was featured at United Recording Studios, and designed by Bill Putnam in 1947. If you venture to a legendary recording studio that was built before 1975, there is a good chance that you may still have the opportunity to experience the use of a natural reverb or echo chamber. For example, both the Sound Emporium in Nashville, Tennessee, which was established in 1969 and Ardent Recording Studios which moved to its present location in Memphis, Tennessee, in 1971, still feature their live reverb or echo chambers. The Sound Emporium also still features an original EMT plate reverb. The earliest reverb units were mechanical devices such as the EMT plate. These devices would feature a metallic plate, coupled with transducers (like miniature speakers) and pick-ups (just like on an electric guitar). I have used one. These units were huge and first designed by EMT in 1957. When a signal was sent to the speakers, the plate shimmered as the source was played and the pick-ups would take this signal or signals back to the console– which would allow them to be a part of the mix and add sheen to voices or even a crack or snap to drum tracks. Live chambers worked in a similar manner. A signal was sent to the chamber, where it was played through speakers and then picked-up by microphones in the inner bowels of the chamber. Then the signal was sent back to the console where it became a part of the mix– giving the source a sense of space and depth. 


Among the first digital units were delays which could be used to thicken sources such as vocals, guitars or drums and could be creatively used to provide a sense of space and depth. But, the first true digital reverb, the EMT-250, first appeared in 1976 and it also offered a variety of settings, including: delay, phasing, chorus, slap and echo. By 1982, with the introduction of the AMS RMX 16, the first digital rack-mount units started to become increasingly popular and more affordable. Digital reverb units such as the Lexicon 480L, the Yamaha SPX 90, the Roland SRV-330 and the TC Electronic M2000 and their successors became popular with engineers and recording studios throughout the mid-1980s and into the early 2000s. Today, (sadly) very few companies produce digital rack-mount reverb units– though pioneering companies such as Eventide and Lexicon still produce fantastic units and a relatively new company, Bricasti, also produces great units for sale in the professional music recording world. If there is any phase of the professional music recording world where software plugins have become almost completely dominant, to the point where it is becoming even increasingly difficult to even find hardware units for sale, it is in the reverb category. 

How do reverb units work?


Whether we are discussing a rack-mount unit, or a software plug-in, reverb units work in exactly the same manner and are also very flexible and easy to use. In fact, reverb units offer more flexibility, power and sound sculpting features than any other type of processor in the world or professional music recording. It is worth noting that even some reverb units are used as dynamics processors– as either multiband compressors or even as brickwall limiters. Since all reverb units are truly digital processors, it is worth noting that quite often, if you find a setting that you appreciate using, you can save it for continued use. 


Digital reverb units or software plugins have the following controls: save, recall, program, decay, pre, lo, hi, in, mix, out and down and up. Save simply allows you to save a program that you have adjusted to your liking for future use. Recall allows you to be able to access a program that you have saved. Decay allows you to be able to set when the processed signal comes to an end. Pre allows you to be able to hear the signal prior to processing, so that you can compare your processing to the original source. The lo and hi functions allow you to adjust the frequency response to the reverb program you are using. The in and out functions simply allow you to control how much of the source signal is coming into the unit and how much of the processed signal is leaving it. The mix function allows you to control how much processing you want to apply to the source signal. The down and up buttons simply reference your ability to access programs that can be used for processing with the unit. Most physical units also contain a scroll wheel which allows you to change or alter the parameters of a program. The program button is where the real magic of a unit or plugin lies because it allows you to be able to access the processing power of the unit or plugin. 

What are some examples of reverb programs?




Plates are reverb programs which are often used on vocals and snare drums. Just like the mechanical plates of the 1960s and 1970s, plate programs give sheen to vocals and a shimmer or fullness to the sound of a snare drum. Plate programs are often determined by size and too, sometimes by the source that they are intended to be used on– such as vocal and or snare plates. It should be noted that the crack you may hear in a snare drum can also be a non-linear program (which instead of a controlled sheen or shimmer, sounds more like a controlled splatter).


Chambers or Rooms


Chambers are reverb programs (or algorithms) which allow you to simulate large spaces or rooms. Sometimes they even give you the ability to emulate the walls or floors of ceiling surfaces (such as brick walls or tiled ceilings). These can be incredibly useful– particularly for drum, piano or vocal tracks.




Halls are reverb programs which allow you to be able to emulate incredibly large spaces such as concert halls, theaters, cathedrals and even stadiums. Though used mostly for drums, they can be also used for vocals, guitars, pianos and acoustic instruments. I rarely saw an engineer use one of these settings, but I can see where they could be used to simulate a “live” feel to a source.



Delays are reverb programs which allow you to thicken a sound source. Sometimes it can also be featured as an ambience program in a unit. Delays are often used on electric guitars to thicken their sound, but they can also be used on vocals, too. 


How did the legendary engineers of the past use reverb?


It is interesting to note that the great engineers of the past may have actually used reverb units more than any other type of processor. As has been noted in other articles, compression was used to the degree that it could be without being noticed and equalization was also to be used only to make minor corrections, if necessary. However, the thunderous drums, thick electric guitars and shimmering, but smooth vocals which defined the popular music of both the 1980s and 1990s came from the use of such iconic reverb units as the EMT 250, the Lexicon 480L and the AMS RMX16 among others. As a young assistant engineer, I watched a true master, the legendary, Grammy-Award winning recording studio engineer, Steve Marcantonio, use the EMT 250 on a vocal to give it the presence that you would hear on the radio and the Lexicon 480L on the drums in such a way that they had both definition and depth. He was such an expert at giving the tracks that he was mixing such a sense of time and place within the context of a song– listeners feel that they can easily connect with the story being told by both the lyrics and the music. In the hands of a legendary engineer, reverb is such a powerful tool.


During the 1980s, it was reverb which defined the drums of rock music. It was the reverb that gave us the powerful vocals of the ballads which would define the pop music of both the 1980s and the 1990s. Reverb, more than any other processing tool in the arsenals of the great recording studios of the period would come to define the music that gave us a new generation of engineers who came of age during the 1970s, whose work would influence the growth of pop, rock and country music during that slice of time from 1980-2000. Without a doubt, if other processors were used sparingly, reverbs were used to greater effect for certain. However, the great technological growth which created the reverb units of the 1980s and 1990s, also made it much easier for these technologies to become an important component of the new wave of software plugins that dominate today’s recording studio landscape. In fact, reverbs were some of the first true plugins to become available with digital audio workstation software programs as either plugins or as a feature of the programs themselves. Due to the nature of this rapid transition, very few companies still make digital reverb units in either rack-mount or 500-series module versions. But, there are still companies which create fabulous reverb units and a few of those will be listed below.

What are some of the great reverb units that were used by the legendary recording studio engineers of the past which are still available today?


It is to be noted that each of the legendary digital reverb units of the past are available in software plugin form today from Universal Audio. However, the following companies still make digital reverb units for sale who pioneered the creation of these amazing processors.


Reverb Units


AMS-Neve– AMS RMX16 (500-series module)

Lexicon– PCM92

Eventide– H9000

Bricasti-- M7 DRS

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