Thank you to Universal Audio for sponsoring this post! Universal Audio is known for making some of the best-sounding reverb plugins and emulations in the world. To learn more about Universal Audio reverb plugins, click this link: Universal Audio Reverb Plugins
In audio production, reverb is a time-based effect that is designed to bring depth and dimension to a recording. But reverb is not just limited to music production. We hear reverb all around us… For thousands of years, humans have built structures specifically designed to harness the power of reverb to make sound behave in particular ways.
In a concert hall for example, the sound from the performer on stage will move outward in every direction. Some of that energy will reach the audience directly, while some energy will bounce around in the room first before reaching the audience.
So if you’re sitting within the audience, you’ll hear thousands of copies of the sound from the performer, each with its own unique tonal quality based on the materials and surfaces it interacts with before reaching your ears. The architecture within many venues is specifically designed to create a beautiful atmospheric reverb for enjoying music.
Types of Reverb
The unique quality of the reverberation within any given space is a function of the size of the room, the height of the ceiling, and the construction materials throughout. Fine tuning the sonic signature of a space like this can provide context to the listener of a film or a video game that contributes to the overall experience. Recording music in a large purpose-built studio can make a drum kit or a choir sound bigger and more powerful. It can be used to bring realism to an acoustic recording or to make larger-than-life electric guitar and vocal recordings.
But don’t worry – you don’t have to have access to a multi-million dollar facility to harness the power of reverb in your recordings. Thanks to the methods that audio engineers have developed over the last century, you and I can use reverb in an instant. Not only that, but we have access to reverbs that are more customizable than ever before at a fraction of the cost.
Back in the early days of recording, if you wanted some reverb on your singer’s voice, you didn’t have many options… You would have had to use the reverb that already existed within the space.
Perhaps you would have adjusted the distance between the microphone and the vocalist to balance the amount of reverb. The further the source is from the microphone, the quieter the direct sound will be in relation to the indirect (or reverberant) sound. At a certain point, the level of the reverberation at the microphone is equal to the level of the direct sound. This is referred to as the critical distance.
A big problem with this method was that you had one chance to get it right. If you placed the microphone too far from the vocalist, you had too much reverb and there’s nothing you could do once the recording was printed to tape. That’s a level of pressure that makes modern music producers like us nervous just thinking about it.
Another option would have been to use more than one microphone. This is the idea behind room mics, which is a technique that is still commonly used today. However, before the invention of multitrack recording in the late 1940s, you still would’ve had to get it right before pressing “record”. But at least you would have the opportunity to adjust a fader for the second microphone to control the blend rather than telling your vocalist to take a step back.
In the 1947 song, “Peg o’ My Heart” by the Harmonicats, we hear what is widely regarded as the first implementation of an artificial reverb.
Rather than using the natural reverberation within the studio itself, producer Bill Putnam Sr. (the founder of Universal Audio) utilized a reverb chamber. More specifically, he placed a loudspeaker and a microphone in the studio’s bathroom. The speaker played the dry signal and the microphone captured the reverberant wet signal.
You’ll hear me use these terms throughout the video: dry and wet. “Dry signal” refers to the sound before the reverb is applied. “Wet signal” refers to the reverberation. Typically, both the dry and wet signals are mixed together to achieve the desired balance in the final mix.
This was revolutionary and contributed to the huge success of the song, giving listeners a taste of artificial reverb for the first time in history. In the audio world, this innovation set off a chain of events that led to studios building designated rooms to be used as reverb chambers.
You don’t need a designated chamber though. Remember – the first reverb chamber was a bathroom! Let’s look at how you can set up a chamber reverb in your studio… Pay close attention here because this framework also applies to setting up modern reverb plugins in a mixing session.
You route the dry signal from a microphone into a mixer or record it. Then, you use an aux send for routing the dry signal out of the mixer and into a speaker within the chamber. Then, you set up a microphone within the chamber that will capture the reverb that is created by the signal playing from the loudspeaker. The signal from the microphone in the chamber will be routed to a separate channel so that it can be blended with the original dry signal. You may need to experiment with the placement of both the speaker and the microphone as well as the blend between the dry and wet signals to get the right sound.
Again, this general setup is still the framework used for setting up any reverb. You use an aux send to route various dry signals to the reverb. This is called an “FX send”. Then the wet signal returns on a new channel, called an “FX return”.
Today, you can use plugins like Universal Audio’s “Capitol Chambers” and “Hitsville Reverb Chambers” to send your recordings through emulations of some of the most famous reverb chambers in history without stepping outside your studio. (We will get into how these plugins are created later in the post).
When using a reverb plugin, you don’t need to route the dry signal out of your DAW. Instead, you can simply create a new track and place the reverb plugin on that track. Then, create a send to route the signal from the drum track over to the reverb track. You can use the FX send knob and FX return fader to achieve the desired blend.
Getting back to the story… dedicated reverb chambers were prohibitively expensive for most studios and they weren’t portable at all. The sound you get from a chamber is also dependent on the room. If you want to change the sound, you need to reposition the loudspeaker, mic, and other objects within the room, and even then your options are limited. But in the late 1930s and 1940s, another artificial reverb solution was born.
Laurens Hammond implemented the first spring reverb into the Hammond Organ, in order to give players a sound that more closely resembled the rich reverberant sound of an organ being played within a large church or cathedral.
A spring reverb operates on a completely different principle. Rather than creating reverb within a physical space, it creates a reverb-like sound mechanically within metal springs. A transducer is attached to one end of the metal springs. That transducer is driven with the dry audio signal, which causes vibrations along the springs. On the other end of the springs, there is a pickup which captures the wet signal. Vibrations in the springs reflect from one end to the other, creating a series of delays that blur together and mimic the reverberation within a room.
By the 1960s, the technology had advanced to the point where it could fit within a guitar amp, giving guitarists the opportunity to add reverb on the fly. Many guitar amps today still have reverb tanks. If you’ve ever wondered what that large rectangular box is within your guitar combo amp, that’s the reverb tank!
The sound of a spring reverb isn’t hyper realistic by any means, but it is iconic. It has a dark, spongy, and sort of bubbling quality that is mostly used as an effect rather than to synthesize an actual acoustic environment.
A German company called Elektro-Mess-Technik (or EMT) created the first plate reverb, called the EMT 140. It was still pretty bulky, but much more affordable and portable than an actual reverb chamber. Not only that, but it offered a much different sound than you could get from a room or a spring and gave the engineer more control.
A plate reverb operates on a similar principle to a spring reverb, but (rather than a spring) a transducer excites a large metal plate. When I say large, I mean LARGE. The EMT 140 was a huge box that contained an 8’ x 4’ plate and weighed more than a quarter ton! Back in college, we had an EMT plate reverb. It needed to be placed in the hall outside, partly because it was so bulky and partly because noise or vibrations around the enclosure could end up in the return signal.
A plate isn’t quite as realistic as an acoustic space and they tend to sound much brighter and smoother than a spring reverb. But they are still a go-to choice for all sorts of instruments when you want to add a luscious, shimmering effect. Not only are plates useful on a single instrument, but they can also be used to create cohesion between several instruments.
Digital Algorithmic Reverb
Once we hit the age of digital audio in the late 1970s, things started to get even more interesting. Rather than using mechanical devices, engineers began implementing digital algorithms to simulate physical spaces. In 1976, EMT came back with the first commercial digital reverb system, called the EMT 250.
Digital algorithmic reverbs use a series of digital delays and mathematical algorithms to create highly realistic reverbs. Maybe “realistic” isn’t the right word here, on second thought. To many listeners, the first digital algorithmic reverbs may have sounded “too” perfect, to the point where they sounded other-worldly. But that wasn’t necessarily a bad thing and it shaped the sound of music throughout the next two decades. To this day, the EMT 250 is considered to be one of the best-sounding digital reverbs ever created.
In 1978, Lexicon (a company co-founded by the inventor of the EMT 250, Dr. Barry Blesser), released the Lexicon 224. It was similar to the EMT 250, but much more affordable. As you can imagine, this made it possible for even more studios to start harnessing the power of digital reverb.
Fast forward to 1999, Sony releases their DRE-S777 convolution reverb. Convolution reverbs are also digital, but they operate on a different principle than the digital algorithmic reverbs we covered previously.
A convolution reverb works with two audio sources, the input signal and the impulse response. The input signal is the dry signal that you’ll be adding reverb to and the impulse response is a representation of the sonic character of a space and how it reacts to different frequencies.
The impulse response is created by playing an impulse in a room (either a quick burst of sound or a frequency sweep) and recording the way the room responds to the impulse. Hence, “impulse response”.
That information is saved and then loaded into a convolution reverb. Through a process of cross-synthesis, the convolution reverb can apply those acoustic characteristics to any sound you pass through it. This means you can collect an impulse response from any physical room or reverb unit and load that impulse response (or IR) into a convolution reverb, essentially adding real spaces to your collection to use later on!
This is a part of the secret behind all of the Universal Audio reverb plugins I’ve demonstrated throughout this video. They created these plugins using a proprietary mix of convolution reverb and algorithmic reverb, called Dynamic Room Modelling. This blend of convolution and algorithmic reverb faithfully recreates the original space while still allowing lots of flexibility and customization within the plugin.
One of the best examples is the Ocean Way Studios reverb, which gives you access to the rooms at Ocean Way Recording, where endless classic records have been recorded – from Ray Charles, to Radiohead, to the Rolling Stones, and so many more.