Few effects can enhance—or interfere with—a mix more than reverb.
When used on individual tracks, it can help situate them in a mix or introduce unnecessary conflicts with other tracks and even other reverbs. When used on multiple tracks or an entire mix, it can help bind those tracks together within a common ambient space, or reduce clarity, power and punch.
Avoiding these problems involves choosing the right type of reverb for the particular job, and understanding enough about what it is doing to recognize problems and solve them. For the purposes of this primer, I’ll assume you’re mixing “in the box” with reverb plugins.
Early Reflections
The earliest artificial reverb effects were created by placing one or more speakers in a room with highly reflective surfaces, sending sound to the speakers, capturing that reverberating room sound using one or more microphones and returning it to be blended with the dry sound. These “echo chambers” had their heyday in the ’50s and ’60s, but some, such as those at Abbey Road, are still in use.
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Plates & Springs
In the late 1950s, two electro-acoustic devices emerged that used transducers to vibrate resonant materials and pickups to capture the results.
The 600-pound EMT 140 Reverberation Unit, which utilized a huge piece of sheet metal, was the first plate reverb. Most reverb plugins feature some sort of plate reverb emulations, but dedicated plugins such as the Universal Audio EMT 140 Classic Plate Reverberator and the Waves Abbey Road Reverb Plates plugins are arguably the most realistic sounding. Plates have a beautifully dense, warm, and open quality that sounds great on practically everything, but they’re particularly revered for what they bring to the party on vocals, snare drums and orchestral strings.
Spring reverbs work much like plates, but use springs rather than a sheet of metal, giving them a “twangier” sound. Although commonly used in guitar amps, studio-grade units such as the AKG BX20 and the Fairchild 658 were also produced. These high-end spring machines sound great on guitars, but also on percussion and other instruments with fast transients, and even vocals. The PSP SpringBox and Universal Audio AKG BX20 are fantastic-sounding plugins.
Ones & Zeroes: Digital Reverbs
Audio Ease Altiverb XL
Digital reverb processers began to appear in the late 1970s, and by the mid ’80s were being used on nearly every record made, almost singlehandedly defining the sound of the entire era. They included the EMT 250 and 251, AMS RMX 16, the Eventide SP2016, and the Lexicon 224XL and 480L processors. These all sound distinctly different and are capable of a huge range of effects. The recreations of these units by Relab Development, Universal Audio, and Waves are all superb.
Today’s digital reverb plugins typically offer a selection of room types (halls, rooms, chambers, etc.), as well as emulations of other reverb types, sometimes including plate and spring reverbs.
Convolution reverbs capture the sonic signatures of existing physical spaces, from tiny rooms to cavernous cathedrals using impulse responses. The Audio Ease Altiverb XL is one of the best, but there are numerous others. Apple Logic X’s includes an amazing Space Designer plugin tool to create your own IRs.
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Insert or Bus?
Sometimes a specific reverb sound is only needed on a single track, such as a gated reverse reverb on a snare drum (think the 1980s…). In such cases, the easiest thing to do is to insert the plugin on that track and use the wet/dry mix control to get the desired blend.
However, it will often make sense to use the same reverb sound on a group of tracks, or even all of them. To do this, create a dedicated aux track for the plugin and route signals to it using the effects sends on the individual tracks.
Optimization
Most reverb plugins come loaded with presets and familiarizing yourself with them will obviously help you to choose the right reverb for the job—but to fully harness that plugin’s sound-crafting capabilities and adapt those presets to specific situations, you’ll need to have at least a working knowledge of what’s “under the hood.”
For example; if something sounds too distant and indistinct, various factors might be involved. Perhaps shortening the reverb/decay time might do the trick, or you might try dialing in some pre-delay to allow the sound to be heard distinctly before the reverb kicks in. And if there’s already some pre-delay, you might adjust the delay time to better sync with the track’s rhythm or tempo.
If the problem is confined to a specific frequency range, you might try experimenting with equalization or the damping control to decrease the reverb at those frequencies. Or you could try adjusting the density parameter. High densities typically result in darker and warmer sounds, whereas lower densities tend to yield airier and more open sounds.
The point is that the settings for any or all of these parameters might contribute to a track sounding too distant and indistinct—and that’s just one example.
Of course, not all plugins feature the same controls, but most at least cover the basics, and until you know what they can do you are at the mercy of the presets. Get to know your tools and you’ll be surprised how often a preset that “isn’t working” will suddenly become perfect just by tweaking a few parameters.
As Sir Francis Bacon said, “Knowledge is power.”
This column addresses topics of interest to recordists, ranging from remedial tutorials on essential terms and concepts (such as this one) to more advanced examples of studio geekery. Next up in On Tracks: “Creative Amp-Miking Techniques.”
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About the Author:
Barry Cleveland is a San Francisco Bay Area-based journalist, author, guitarist and composer. He was an editor at Guitar Player magazine for 12 years and at Mix and Electronic Musician magazines before that. His book, “Joe Meek's Bold Techniques” is a cult classic, and he also contributed to the book “Whole Lotta Led Zeppelin.” He has released five albums and composes music for film and television.