What is reverb and how does it differ from echo or delay? What makes reverb different from an echo? What makes it different? It is used in music production. How does it get created?
This is the sequence of questions you will have to ask when you first start to consider this natural sound effect. People don’t realize that they are familiar with reverb, but they have never attached a word.
In fact, we all hear reverb almost every day, and most people have never heard any sound or piece of audio without it. Unless we are one of very few who have ever been in anechoic chambers, then we don’t know. It’s quite strange when you hear it.
Let’s start by giving a more technical explanation of what reverb is, how it works, and then discussing the various types of reverbs and the acoustic environments that they imitate. You’ll be able to understand the effect and how it works once we’re done.
What is Reverb?
Understanding the nature of this effect is key to understanding it. We’ll discuss later how to artificially reproduce it for audio production such as music and movies.
EXPLAINING REVERB THRU DELAY & EARCHO
Most people are familiarized with delay, echo. A delay can be described as the duplication of audio that is repeated after a set amount of time. Echo is exactly the same as echo, except that the audio is repeated over and over again, separated by the same time period, becoming quieter with each repetition.
If you stood at the Grand Canyon’s edge and shouted “hello!” into it, you would hear someone sounding just like you. The delay time is the second “hello”.
Imagine you are standing at the bottom Grand Canyon, with tall walls rising in front and behind. You could shout “hello” into a wall in front of you, and the sound would bounce off the wall into the back wall. The sound then reverberated back into the front wall. It got quieter and lost its energy.
This is what reverb looks like. Reverb is an echo that repeats many times in a fast and efficient manner. You hear a “smear out” of the sound as it changes over time. This effect is created by reflections bounced off surfaces repeatedly.
This is a common occurrence. Indoors, sounds bounce off walls, bookshelves, cabinets, and desks. Outdoor sounds reflect off buildings exteriors, streets, trees, signs and even the air. It’s impossible to escape it in nature. Just like light, sound reflections can be found everywhere.
What is the Reverb Effect?
Reverb is simply an addition to recordings or live sound systems to make them sound more natural.
Studio recording is where audio tracks are recorded as dry as possible. This means that there is no reverb or unwanted effects from the room. This is done by using acoustic therapy which absorbs sound energy to prevent it from reflecting off the walls.
Live performances may not be possible in large venues or auditoriums that have the reverberation required by songwriters. These cases are where we add reverberation in order to create an imaginative or emotional effect.
HOW THE RECORDING STUDIO REPRODUCES REVERB
Three historical methods have been used to create reverb. The second and third methods are rarely used today, while the majority of applications are created using the third. These are:
We have to make the sound last over time by using reflections. Each reflection must decrease in amplitude until it ceases to be audible. Then, we have to be able control the frequencies that are highlighted, the rate at which the amplitude decreases and the reverberation times, so that it is a useful effect.
Psychoacoustic studies have shown that distinct echoes can be heard if the sound’s reflections are within 50 milliseconds. These reflections must be reproduced one after the other, and at an incredibly high speed. How can this be done?
We started making reverb in natural echo rooms (a room we loved the sound of) back in the beginning. We eventually built them according to our specifications but it was costly.
This method was used by Phil Spector, a well-known music producer. He created his Wall of Sound style which was used in songs by The Beatles and The Beach Boys. The band would perform in the chamber, or the songs would be played through the speakers and re-recorded.
Because you had to build a new room to adjust the effects, these chamber reverberators were not popular. This was costly and needed space in the studio to be built. They are still used for studies but not much in studio recording.
Some bands still look for special recording spaces. Led Zeppelin recorded the song “When the Levee Breaks” on a stone staircase. Yes recorded in the warm sound of a wooden barn, and even in a pub Jon Anderson loved. However, these unusual decisions are less common since the 1960’s.
Plate-reverberators are the next major breakthrough. A transducer, which vibrates the cones of speakers using a large thin plate of metal sheet, is used to make this vibrate. This produces sound that is then recorded with contact microphones.
This is the revolution in audio recording. The reverb can be added to the original source at different volumes, or modified using signal processing. You can alter the flavors of reverb depending on the thickness of the plates or the power of the transducers.
The Beatles and Pink Floyd are perhaps the most well-known early examples of plate reverb. They used this invention extensively at Abbey Road Studios. The Elektro-Messtechnik EMT 140, their unit, weighed 600 pounds. Pink Floyd’s music has always sounded dark and haunting because of the plate method.
Spring Reverberators look very similar to their plate counterparts. However, the transducer attaches to one end a metal spring while a pickup is attached at the other to record the result. Laurens Hammond, the organist of fame, was granted the patent for the first spring-reverb tank in 1939. However they were never widely used beyond organs and guitar amplifiers.
These were cheaper to make and smaller than plates. However, they never gained popularity due to the unwanted effects of spring movement (above the intended vibration). Although guitarists love to rock their amps and make thunderous sounds, many wouldn’t want this to happen by accident.
Computers have made it possible to emulate any method and create new reverb effects. Signal processing is the process of adding effects to audio signals using algorithms that mimic electronic circuits in parallel and serial. They also mimic analog systems.
This is how best-reverb pedals function for guitar effects units. This is how VST plug ins work in your Digital Audio Workstation. This is how synthesizers add the effect. This is the best current method, and it will probably remain so for ever. Both pure emulation and convolution reverb (taking an example of a reverb’s impulse response to model space) can be done digitally.
The Different Types Of Reverb
It is likely that you have realized that a small room can produce a different type of reverb to an auditorium than one in a larger space. Although there are many’verbs’ that you can create, most of them fall within a few main categories and a few special ones.
These are the reverb types that we have chosen (and their characteristics).
- Room Basic, Warm, and Short
- Hall – Even, Neutral, Long
- Chamber Complex, Colorful and Medium
- Plate– Smooth, Bright and Variable
- Spring Metallic, Dark, Variable
- Ambience – Ambiguous, Digital
There are also two other special applications: dereverberation (removing reverb) or reverse-reverb (having it swell into the original sound instead of trailing after). These are the 7 types of reverb. Learn more in our article, 7 Types of reverb: The Different Flavors of Soundscape Design.
Using Reverb in Live Sound
Reverb can be applied live sound at the mixing board, on a rack mounted unit off-stage, or through an effect pedal controlled by the musician. Important is the inability to spend too much time cleaning up isolated reverb (if any)
Keep in mind that the more reverb is used, the less the instrument’s “cut through” the mix, making it less intelligible. Increasing the volume of instruments will cause the mix to become unintelligible and disrupt the flow.
Reverb volumes should be kept low. Higher levels are permissible for sparse instrumentation or solo performances. Additional reverb is not necessary if performing in large cathedral halls. However, it can make the mix worse if there is a live audience that is allowed to talk and dance.
Reverb – Recording and mixing
Mixing reverb takes a lot of time and effort to manage the reverb bus. This allows you to optimize its use while keeping the mix clear. It is a good idea to add an equalizer on the bus to pick out middle frequencies and reduce clashing.
Example EQ curve for the Reverb bus
Mixing engineers and studio engineers prefer instruments to be recorded completely dry with a little compression. Reverb should not be recorded at the input because it will “commit to tape” the effect and cannot be undone or altered. Clarity is maintained by equalization of the reverb bus
A mix can be achieved with equalization, the addition of a pre delay (gab between the source audio and the start of the effect), mono and stereo options, and the panning or phasing of the effect. This allows for optimal clarity and a rich amount of reverb to create a stunning soundscape.
What then is Reverb?
Reverb, as it is commonly known, refers to a series or echoes that occur in rapid succession and can’t be listened to individually. They combine to create one sound, which is similar to a “smear out” of the original sound. It is a common phenomenon in nature, and it rarely fails to occur.
Our computer scientists and sound engineers can make this effect a reality. We can alter any aspect of the effect to our liking, thanks to their genius. It is used to make recorded sounds sound natural, simulate another acoustic environment or create an emotional response. We have not only explained what reverb is, but also shown you how to create it and use.