Sculpting Digital Reverb for Guitar

Applying reverb to guitar used to be simple.
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Applying reverb to guitar used to be simple. You turned up a control on your amp to mix in some ’verb, and then kicked your amp for that glorious “sprongggg” that only spring reverbs could achieve. But today’s digital reverbs have a lot more options, so here are some useful tweaks for guitar.

PRE-DELAY

This emulates the time between a sound occurring in a room, and how long it takes to hit surfaces and start creating reflections. With lead guitar, a short pre-delay (50ms-100ms) keeps the reverb from stepping on note attacks, which maintains their definition, and gives the lead more clarity in the mix (Fig. 1).

DIFFUSION

Reflections create even more reflections, and diffusion (sometimes in conjunction with a density parameter) controls how the echoes build up over time. More diffusion imparts a thicker vibe with more bloom as the reverb decays. The easiest way to hear how this affects sound is with a snare hit. Low density settings space the echoes further apart, giving a “marbles bouncing on steel plate” effect. Higher densities smooth out the sound more as it decays. With sustaining sounds—like voice and lead guitar—lower densities are often preferable, because for a given decay time, they apply reverb more sparingly. But with percussively strummed acoustic guitar, moderate density can add a richness that fills in the spaces between the sharp note attacks.

HIGH AND LOW FREQUENCY DECAY

Fig. 2—This tab in Overloud’s Breverb 2 sets separate high- and lowfrequency decays and their respective cutoff frequencies. There are also damping controls, and a low-cut option to reduce mud.

Many reverbs have separate decay controls for the high and low frequencies, complemented by a control that sets the crossover frequency. Optimum settings depend on what’s happening in the mix. With a busy mix and a David Gilmour-style lead line, you’ll probably want more high-frequency decay (Fig. 2), as the reverb will float above the mix and impart extra ambience. But for rhythm guitar, emphasizing the lower mids can increase the low-end power, as long as there aren’t other instruments (such as a piano’s lower ranges) competing for the same sonic space.

DAMPING

High frequencies decay faster because they’re more readily absorbed by people, fabric, etc., than lower frequencies. If you’re using a lot of highfrequency decay, and you want a natural sound, increase the amount of damping to reduce highs as the sound progresses.

CONVOLUTION VS. SYNTHETIC REVERB

Convolution reverbs measure a room’s characteristics and apply those characteristics to your signal. Synthetic reverbs use algorithms to model the sound of a room—more like impressionistic art compared to convolution reverb’s “photograph.” My rule of thumb is if you want to sound like you’re playing in a physical space, use a convolution reverb. For more of a tweakable “effect,” try synthetic reverb (although it’s capable of highly realistic sounds, as well).

Craig Anderton has played on or produced more than 20 major label releases, mastered hundreds of tracks, and written dozens of books. Check out some of his latest music at youtube.com/thecraiganderton.

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