Effects for Live Sound: Processing That Enhances Performance

Effects for live sound add dimension, polish, and character to performances. Reverb creates space; delay adds rhythmic interest; compression controls dynamics. Applied well, effects enhance without drawing attention to themselves. Applied poorly, effects obscure performances in wash and artifacts.

Reverb Applications

Reverb simulates the reflections of acoustic spaces, adding depth and realism to sources that might otherwise sound dry and isolated. Vocals, snare drums, and certain instruments commonly receive reverb treatment.

Room and plate reverbs suit live sound better than large hall programs. Shorter decay times avoid buildup that muddles mixes in already-reverberant venues.

Pre-delay separates the direct sound from reverb onset, maintaining clarity while adding space. Settings of 30-80 milliseconds prevent reverb from smearing transient definition.

Less reverb is usually better in live contexts. Venue acoustics already provide natural ambience; adding more through processing can create excessive reverberant wash.

Delay Effects

Delay repeats the input signal after a specified time interval. Single repeats, multiple repeats, and modulated delays serve different musical purposes.

Vocal delays at tempo-synchronized intervals (quarter note, eighth note) add rhythmic interest to vocal lines. Feedback settings control how many repeats occur before the delay fades.

Slap-back delay with single short repeat (80-150 ms) adds presence without obvious effect character. This subtle enhancement thickens vocals without sounding like obvious delay.

Stereo delay with different left and right times creates width. This technique adds dimension but requires careful level management to avoid clutter.

Dynamics Processing

Compression reduces the dynamic range between quiet and loud passages. Applied to vocals, compression maintains consistent presence in the mix despite performer dynamics.

Moderate compression ratios (2:1 to 4:1) suit most live sound applications. Extreme compression sounds unnatural and removes the performance dynamics audiences expect.

Attack time settings determine how quickly compression engages. Slower attack preserves transients; faster attack catches everything. Vocals typically benefit from medium attack (10-30 ms).

Release time controls how quickly compression releases after signal drops below threshold. Settings that match the musical tempo or allow natural decay sound most musical.

Gate Applications

Gates silence channels when signal drops below threshold, reducing bleed and noise. Drum microphones commonly use gates to separate individual drum sounds.

Threshold settings distinguish between desired signal and bleed/noise. Setting threshold too high cuts off legitimate signal; too low allows bleed through.

Attack time should be fast enough to catch transients without audible chopping. Drum gates often use attack times under 1 millisecond.

Release time prevents unnatural cutoff of sustained sounds. Settings that allow natural decay—50-200 ms for drums—sound more transparent than abrupt cutoff.

Effects Send Configuration

Effects typically receive signal through auxiliary sends rather than inserting directly on channels. This parallel configuration preserves the dry signal while adding processed signal to the mix.

Post-fader sends track with channel fader movements. When the channel level changes, the effect send changes proportionally. This suits reverbs and delays where effect amount should relate to dry level.

Pre-fader sends remain constant regardless of channel fader position. This suits monitor sends but is rarely appropriate for main mix effects.

Return channels receive the effect output, allowing EQ, level control, and routing of the processed signal. Effects returns may be stereo even when sends are mono.

Built-in vs External Effects

Digital mixers include built-in effects eliminating the need for external processing. The quality of built-in effects varies; premium consoles offer professional-grade processing.

External effects processors provide dedicated high-quality processing. Units from Lexicon, TC Electronic, and Eventide serve professional applications where onboard effects fall short.

Hybrid approaches use onboard effects for most applications while adding external processing for critical sources or special effects.

Effects Level Management

Effect levels should enhance without becoming prominent. When effects are noticeable as effects rather than enhancement, they are typically too loud.

The ratio between dry signal and effect depends on musical context. Intimate acoustic performances use less effect; energetic rock performances may use more.

Muting effects between songs prevents reverb tails and delay trails from carrying into silence. Automation or manual muting keeps transitions clean.

Live Sound vs Studio Approach

Live sound effects serve different purposes than studio recording effects. Studios often use effects creatively; live sound uses effects supportively.

The existing venue acoustics affect how much artificial reverb sounds appropriate. Dry rooms may need more reverb; reverberant rooms may need none.

Feedback potential increases with reverb and delay. These effects return signal to microphones through speakers, potentially creating feedback loops. Use effects conservatively when feedback is a concern.

Effects During Performance

Adjustments during performance should be subtle. Drastic effect changes draw attention and distract from the music.

Scene changes on digital mixers can recall different effect settings for different songs. This automation suits well-rehearsed productions with predictable setlists.

Real-time effect adjustment—more reverb on a ballad, less on up-tempo songs—enhances the performance when executed smoothly.

Common Mistakes

Excessive reverb creates wash that obscures lyrics and performance detail. The instinct to add more reverb usually leads to too much reverb.

Effects on instruments that don’t need them clutter the mix without benefit. Not every channel needs reverb or delay.

Using long reverb programs in reverberant venues creates problematic overlap between artificial and natural reflections.