Everything you need to know about reverb

Audio engineers and music producers are often after a very direct sound. This is the reason microphones are normally placed very close to the source. This captures the source with a lot of detail but also takes out most of the natural ambiance of the room. Most producers usually prefer to use emulated spaces that are over often exaggerated and completely different from what you’d normally hear in the real world. The ability to use multiple types of reverb with different tonalities helps give the production depth, contrast and keep things interesting. It also helps engineers deliberately place certain sounds in a mix, for instance, I may want to drench the pad synth to make it sit further back in the mix so it doesn’t interfere with the lead synth line.

Panning gives us the ability to move sounds left and right and time-based effects give us the ability to move sounds forward and back.

What is reverb?

Reverberation or more commonly referred to just as reverb is the sound created when sound waves are being reflected and interacting with the world around us. The time it takes these reflections to dissipate or be absorbed into other objects is referred to as the decay time.

When a sound is made in a room, what we are actually hearing is not just the sound directly from the source but also the waves reflecting off of all the surfaces in the room that are then bouncing back into our ears. For instance, if someone yells at you, you’re not just hearing the waves that are coming directly from the person’s mouth but also how it is interacting with the physical surfaces and walls of the room you’re in.

I have a very early memory of asking why it sounded better when I sang in the shower. The highly reflective tile in most bathrooms creates a natural reverb that helps with your pitch which makes it more fun to sing into. I always recommend when recording a vocalist to make sure they are monitoring their vocals with effects like reverb to create the best sound possible. If the artist sounds good in their headphones it will yield a better performance than if they were just listening to their dry vocals straight from the microphone.

The history of reverb

Artificial reverb or reverb that isn’t the natural ambiance of the room that you’re recording in, was first used on a musical production by Bill Putnum and Robert Fine in 1974. Both of these pioneering audio engineers separately came up with the idea to put a speaker in another room, record it with a microphone and then mixed it back in with the original dry sound. Decay times could be adjusted by changing the room acoustics or by moving the microphones. The problem is these require an entire room for just a single reverb, something we can do today with a free plugin.

Hammond started putting reverbs in their organs in 1940 and Fender started putting them in their amps in the late 1950s but it wasn’t until 1957 when EMT released the 140 plate reverb, that studios were finally able to ditch the chambers that took up an entire room for something a little more practical. The 140 plate was the first artificial reverb that studios adopted because it had an incredible sound that could measure up to the finely tuned chambers that were found in the elite studios of the time. The 140 plate was an enormous success and its sound is so coveted that developers still continue to try and replicate the gorgeous sound. In 1976, the EMT 250 was released which was the first-ever digital reverb which opened the doors to seemingly limitless possibilities.

There are three ways an artificial reverb is commonly created. The first type of reverb available to recording studios required a physical or real element, such as an entire room or a humongous steel plate.

The next two types, algorithmic and convolution are digitally based. With greater computer processing power came the ability to develop convolution reverbs which use impulse response or IR samples that are recorded in a real physical space by sending a burst of white noise into the room and recording the decay. This gives engineers the ability to capture and reproduce the sound of any room or their favorite plate or spring reverb. These impulse responses are designed to mimic the decay that was originally recorded which makes them useful when trying to replicate a specific type of ambiance. This makes them extremely useful in post-production when you need to rerecord audio that originally was recorded somewhere else. An impulse response taken in the original location would allow the mix engineer to add in the same sound of the room when rerecording.

The second way digital reverb is created is through the use of algorithms. The EMT 250 is the first digital reverb ever made and was algorithmic based. I actually had the honor of talking with Bill Blesser who was the original designer, you can view the entire article here. Algorithmic reverbs are created using a mathematical formula that is calculated and rendered by the processor in the hardware or your computer if its a plugin and then spit back out your speakers.

These are the 6 most important types of reverb you’ll need to know about.

Room reverb

You know what a room is right?

Room reverbs create the response of a… you guessed it.. a room. Usually, a small room as these reverbs most commonly have a short decay time typically under 1 second. This reverb can give the sound life and put it in a space that our ears are familiar with. Because of this familiarity, it adds a really pleasing effect to our ears and aids in getting sounds to fit together in a mix. I commonly find myself using room reverbs on drums especially snares, percussion and other acoustic instruments that are a bit too dry but don’t need a longer reverb with an audible decay. Because the decay time is so short, the reverb is usually felt rather than heard when putting it in a mix.

Plate reverb

Plate reverb, like the aforementioned legendary EMT 140 that consists of an 8 x 4 x 1-foot wood box with a sheet of steel hanging inside. A transducer then sends the signal into the sheet of metal which causes it to vibrate, the result is then picked up via another transducer and mixed back into the dry signal. The length of the decay is adjusted via a damping mechanism which can also be controlled via a remote. When I interned at Trout Recording in Brooklyn, New York, owner Bryce Goggin had just purchased a 140 plate but it didn’t have a remote. I fondly remember being assigned the task of going down to the basement to adjust the decay time whenever necessary.

Plate reverbs have a very pleasing sound and work well on pretty much everything. Sound waves travel faster in the metal plate than they do in the air which gives them a higher density, smoother tail and ultimately a very desirable sound that engineers and producers all over the world have grown to know and love.

The famous Radio City Music Hall in New York City.

Hall reverb

This type of reverb simulates a finely tuned concert hall. Concert halls are auditoriums that are designed with acoustics being the main priority. These halls are meticulously tuned to remove any negative artifacts that can be detrimental to the sound such as rings, standing waves, and uneven tonal response. These are a classic artificial reverb that became popular with the rise of digital time-based effect units. Since these rooms are designed for optimal acoustics it’s no surprise that they are often emulated. Halls can be used on just about anything with successful results. One of the most popular hall reverbs is the Lexicon 480L which can be found at many of the most esteemed studios around the world.

Chamber

Chamber reverb is usually a small to medium sized room that is made up of different types of reflective surfaces that are strategically placed at different angles. A send and return are set up using speakers and microphones. Chambers offer a thick, dense and lush reverb without being overpowering. These are most commonly found on vocals and acoustic instruments but are great for any source that needs some character.

Echo chamber

Spring reverb

Like a plate reverb except instead of a sheet of metal, these use an actual spring. Spring reverbs most commonly have a short or medium decay time and is used on guitars and keyboards because they are small enough to fit into amplifiers. Don’t let that fool you, spring reverb can sound good on a number of different sources including vocals, synths, piano and of course guitars. The sound can be described as metallic like a plate but bouncier, more lively but with less depth. 

The inside of a spring reverb tank.

They are most popular for the sproingy sound that they make when you physically shake the reverb tank causing the springs to jostle around. Using a ton of spring reverb is a requirement when playing surf rock or producing dub music. In the late 1960s, AKG released the BX series of spring reverb units that became popular with recording studios.

Ambiances

These are extremely short reverbs with reflections happening between half a second and shorter. This type of reverb is mostly used to add tone since the decay time is so short, they are more likely to be felt rather than heard. Adding an ambient reverb return and sending multiple sources to it can have a nice gluing effect.

If you got this far, you finally know enough about reverb, maybe too much. Now it’s time to get out there and start reverbing!!! Put a reverb there. Put one over there. Put some reverb everywhere!

Related articles:
Can you tell the difference between real and fake plate reverb?
20 quick and easy tips that will improve your productions
5 mixing mistakes that I used to make… and how to avoid them
The “your mixes sound bad in the car” phenomenon

David Silverstein

David Silverstein began engineering at the age of 14 when he purchased a Fostex four track cassette recorder. After high school he enrolled at Five Towns College where he graduated with a Bachelors of Professional Studies in Business with a concentration in Audio Recording Technology. He has worked under renowned engineers and producers Jim Sabella (Marcy Playground, Nine Days, and Public Enemy) and Bryce Goggin (Pavement, Spacehog, The Ramones and The Lemonheads). David currently works out of Sabella Studios in Roslyn, NY.