Optimizing Reverb for Vocals

Reverb is a crucial part of most vocal recordings, so make sure you get it right

By Craig Anderton

Reverb and vocals were made for each other; few recordings put the voice totally out front, with no ambience. However, there’s much more to getting the right vocal reverb sound that just dialing up a preset and crossing your fingers.

ONE REVERB OR MANY?

Back in the stone age of recording, a recording had one reverb, and all signals were bused to it. Often the vocals sent more signal than some of the other instruments, but the result was a cohesive “group” sound.

Later on, studios often used a specific reverb for vocals. Much of the motivation for doing this was to make the voice more distinctive, and if the studio had a plate reverb, that was often the reverb of choice because it tended to have a brighter, crisper sound than a traditional room reverb. This complemented voice well, which tends not to have a lot of high-frequency response.

With the advent of digital reverb, some people went crazy—one reverb type on the voice, gated reverb on drums, some gauzy reverb on guitars, and maybe even one or two reverbs in an aux bus. The result is a sound that bears no resemblance to the real world. That in itself is not always a bad thing, but if taken to extremes your ears—which know what acoustical spaces sound like—recognize the sound as “phony.” Unless you’re going for a novelty effect, this can be a problem.

If your digital reverb has a convincing plate algorithm, try that as a channel insert effect on vocals and use a good room or hall reverb in an aux bus for your other signals. To help create a smoother blend, send some of the vocal reverb to the main reverb (Fig. 1).

Fig. 1: This mixer routing in Pro Tools shows a Universal Audio EMT140 plate reverb inserted in the vocal path, but with an additional send going to the main “hall” reverb that processes the other instruments.

This will likely require dialing back the vocal reverb level a bit, as the main reverb will bring up the level somewhat.

TO DIFFUSE, OR NOT TO DIFFUSE?

A reverb’s diffusion control increases the density of the echoes. Higher diffusion settings give a less “focused” sound, producing more of a “wash.” This is helpful with percussive instruments, because percussive sounds create sharp echoes with digital reverb. Turning up diffusion gives a smoother sound. However, a voice isn’t percussive, and high diffusion settings can produce an overly “thick” sound. This violates the First Rule of Vocal Reverb: The reverb should never “step on” the vocal. Instead, try low diffusion settings (Fig. 2).

Fig. 2: Low diffusion settings, as shown here in the Waves Renaissance reverb, are often preferable for vocals compared to high diffusion settings.

This produces a reverb sound that blends in with the vocals rather than sounding like a separate effect that lives apart from the voice.

WHAT ABOUT EQ?

Many reverbs have adjustable high and low-frequency decays, or at least levels, with a crossover point between the two (Fig. 3).

Fig. 3: The Breverb reverb from Overloud has separate decay times for the high and low bands.

With voice, I tend to use a longer high decay than low decay. This gives a reverb splash to the “s” sounds and mouth artifacts, while reining in low frequency reverb components that have the potential to make the sound more muddy. Remember, crispness with vocals is usually a good thing, because it increases intelligibility—as long as you didn’t already add massive amounts of high frequency EQ to the vocal itself.

Experimentation is key to finding the right crossover point, because of differences between male and female voices, tonality, range, etc. Start around 1kHz and move upward from there until you dial in the right sound.

REALLY, THERE’S NOTHING LIKE AN ACOUSTIC SPACE

Sure, digital reverb algorithms have made tremendous progress in the past few years. Nonetheless, there’s nothing quite like a real acoustic space to give an ambient quality that remains elusive to pin down in the digital domain.

But this doesn’t mean you need a concert hall to get a good reverb sound. Even relatively small spaces, if they’re reflective enough, will do the job. Simply send an aux bus out to a speaker in your bathroom (remove any towels or soft surfaces, and pull shower curtains back), then put a mic in the bathroom and bring its output back into a mixer input.

Send some of your vocal channel’s digital reverb output through an aux bus into this space, and add just enough of the acoustical reverb to provide the equivalent of “sonic caulking” to the digital reverb sound. The room will add early reflections that will be far more complex and interesting than all but the very best digital reverbs can deliver—and you might be very surprised just how much this can “sweeten” up your sound.

And if you’re in an experimental frame of mind, consider adding some feedback to the room reverb: Send some of the room reverb return back into the send output feeding the speaker. Be very careful, though, and keep the monitors at extremely low levels as you work on the sound—you don’t want a major feedback blast!

Craig Anderton is Executive Editor of Electronic Musician magazine. He has played on, mixed, or produced over 20 major label releases (as well as mastered over a hundred tracks for various musicians), and written over a thousand articles for magazines like Guitar Player, Keyboard, Sound on Sound (UK), and Sound + Recording (Germany). He has also lectured on technology and the arts in 38 states, 10 countries, and three languages.