Pro Tips, Tutorials

Delay, Modulation, and More: An Introduction to Audio Effects

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Even if you’re just beginning to work with audio in your recording or video software, you’re probably familiar with audio effects. What an audio effect does is straightforward — it simply alters how your audio sounds. The ability to add audio effects, whether it’s modulation, delay, or reverb, presents itself in countless scenarios working with sound. For instance, guitarists use audio-effect stomp boxes to add depth and richness to their instruments, editors use audio effects in Adobe Premiere Pro to alter room tone to sound as realistic as possible, and engineers use audio effects in racks or on mixers to make live performers sound optimal.

Below is a guide to several basic audio effects and how you can use them in your digital audio workstation. I’ll be using a dry (unaffected) acoustic guitar track I recorded to Logic Pro to demonstrate how each effect sounds:


 

Reverb

Reverb is intended to replicate how audio sounds in certain rooms. Notice how your voice sounds different in a bathroom than it does in a concert hall? That’s because the sound is bouncing off different elements in the room and the resulting “decay” you hear (the sound getting quieter and quieter) is reverberation. Adding reverb can give your sound more realism by adding a trail of audio decay you’d hear if someone was actually creating that sound right in front of you. Below, I’ve added Logic’s preset PlatinumVerb effect to show how the audio effect replicates a concert hall.

In Logic, you can click anywhere on the effects rack and scroll to the one you’d like to add:

The PlatinumVerb preset I added:

Here’s the guitar track before adding reverb:

After adding PlatinumVerb:

It sounds like it has a lot more “space” to it now, doesn’t it? You have a ton of flexibility using reverb. Play around with different room sizes and lengths of audio decay to get different results.

Reverb can also be used to add an ethereal, “ghostly” sound to your recording by creating long trails of decay. Get a little experimental and see the kinds of space you can create with a reverb effect.

I recommend creating a bus send and sending similar instruments (e.g., guitars, vocals) to the same reverb-effect send so the resulting audio decays don’t clash (see how to create buses in Logic here and in Ableton here).

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Distortion

Distortion is meant to mimic amplifier tubes getting too loud, causing the audio to clip and distort. That scratchy, gross sound you hear when you blast your car stereo too loud? That’s distortion. Distortion is created when adding a lot of gain, which originally meant the amount of electrical output power necessary to amplify an audio signal. You can add distortion to any number of sounds in your project, to add saturation and character to a sound by overdriving it. Since I have an acoustic guitar, I’m going to add a small amount of Logic’s Distortion preset to give it a meaty, overdriven sound.

Here’s the acoustic guitar before adding distortion:

And after adding distortion:


 

Delay

Delay is a popular effect due to its versatility and endless number of uses. Delay takes the audio signal and plays it back after a certain duration, like an echo. Delay was originally created with tape loops, where an audio signal (like a guitar) was recorded both to a main tape recorder and to a second tape recorder, which played the initial audio signal again over and over, resulting in a “delay” effect. Digital delay replicates this effect, and can be manipulated by how long the audio repeats, what length of the original audio gets repeated, and how much volume of the original audio you can hear versus how much volume of the delayed sound you want to hear.

I added LogicPro’s Echo preset and set the delay to repeat at certain music intervals.

The acoustic guitar before adding delay:

Logic Pro’s “Echo” effect with the delay set to repeat at 1/4ths:

The track with delays set to repeat at 1/4ths:

Logic Pro’s “Echo” effect with the delay set to repeat at 1/8ths:

The track with delays set to repeat at 1/8ths:

Logic Pro’s “Echo” effect with the delay set to repeat at 1/16ths:

The track with delays set to repeat at 1/16ths:

It’s pretty straightforward, and delay is a great effect to add to give depth to vocals, percussion, and synthesizers. You can play around with different feedback settings (how long the delay repeats) to get some crazy sounds.

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Modulation

Modulation is another signal-effect process that’s a little similar to delay. Modulation takes the original audio signal, delays it by only a few milliseconds, and then affects it again through a number of different processes. The different processes and how they differ comprise the three most popular modulation effects; flanger, phaser, and chorus.

A flanger effect involves playing the original audio while a delayed signal (by a few milliseconds) plays under it. The resulting clash of frequencies creates a “swoosh” type of sound. I’ve added Logic Pro’s preset Flanger effect. Check it out below:

The track before flanger:

After flanger:

A chorus effect also plays the original audio with a delayed signal, but then adds an LFO (low frequency oscillator) that adds a rhythmic “pulse” to certain frequencies in the sound. The result is a dreamy, wobbly sort of sound. Check it out with Logic Pro’s preset Chorus effect.

Before chorus:

After chorus:

A phaser effect plays the two audio signals at once, although the volume of each signal varies while it plays. The resulting sound is a wobbly, whooshing, sweeping sound similar to chorus and flanger. Check it out with Logic’s preset Phaser effect.

Before phaser:

After phaser:

Tremolo takes the audio signal, varies its volume up and down, then pans it rapidly in each channel. The resulting sound is a “stuttering” effect of sorts. Listen to how Logic Pro’s Tremolo preset treats my acoustic guitar.

Before tremolo:

After tremolo:


 

Dynamic Processing

Dynamic processing involves the use of effects like compression, limiting, and certain EQing to alter the volume and amplitude of elements in your tracks. For an in-depth explanation on these processes, check out our articles on EQing and mastering.


Man Using Mixing Console by Dolgachov

There are countless audio effects to experiment with. Begin with these examples, then branch out. In the meantime, leave any questions or comments below, and stay tuned for more audio tips and tricks!

Top image: Hands on Mixing Console in Music Recording Studio by Dolgachov