The Ultimate Guide to Audio Effects

Let’s dive into exactly what you need to know about 5 of the most common audio effects. Understanding how they work can give you a much deeper understanding of them, making you a better and faster producer than the majority of the producers who use them without understanding why. We’ll also mention some differences between analog and digital units and how to blend their sound with our newest plugin, Finisher RETRO! It’s designed to bridge the gap between the two, and we’ll mention presets in places you might find it useful to demonstrate ideas.

If you want to dive deeper into how to use each effect type in the context of a mix, check out our articles How to Mix a Beat and How to Mix Guitars — for a lot more juicy details! This article will help you understand how these tools work and their overall purpose on a broad scale, which is super useful for when you hit a block from always using tools in the exact same way. The 5 audio effects covered in this article are:

1. EQ
2. Compression
3. Delay
4. Distortion
5. Phasing and flanging

EQ

The most fundamental purpose of EQ is to reshape the frequency spectrum of an audio track, either by boosting, cutting back, or completely filtering out certain frequencies. When a mix is cluttered, this is typically the first tool you should reach for to correct the frequency balance and make everything fit together better. EQs work by shifting an audio signal by shifting its phase (its position in time) very slightly, creating new peaks and valleys in the waveform that change its frequency response. In the digital world, there are complex equations that handle this, creating a copy of the signal and introducing ultra small timing delays in the copy to change the sound of the audio passing through.

The basic principle of analog EQ is the same, but the circuit design is very different from its digital counterpart. If you get the opportunity to try a good analog EQ, take it — there’s a warmth in them that’s difficult for digital EQs to replicate! Depending on the EQ, you also might get a cleaner sound from an analog unit when boosting frequencies, versus a digital EQ which could sound thin when you try to push it in the same way. You can cut frequencies safely, however — this often produces a more natural sound.

Compression

This might be the most difficult audio effect to understand, so don’t worry if it doesn’t make sense immediately. In short, compression makes an audio signal sound more consistent — if its volume is all over the place, a compressor will give it more focus; if it has some dynamic range, compressing it will completely squash it. In general, only use compression when you know why you’re using it; otherwise, you may end up completely squashing your audio and sucking the life out of it (i.e. only use it when you know you need it).

A compressor looks at the audio signal coming in and evaluates whether the signal is over the threshold you set and decreases it by a ratio. For example, a 4:1 ratio means that for every 4 decibels (dB) over the threshold, only 1 will make that through — think of it as reducing the volume to one fourth of everything over the ratio. You then use what’s called makeup gain to increase the audio signal back up to the original average volume. In digital compressors this is pretty straightforward — but analog compressors are a bit different ...

In fact, there’s a phrase that became synonymous with the famous LA-76 compressor: “1dB magic.” You could simply run a track through the compressor, apply the slightest amount of compression, and yet it would sound much warmer. With analog compressors, you’re not simply trying to control the volume (because a digital compressor can do that just fine, and for cheaper) — each classic analog compressor has a distinct sound, and sometimes you just want very light compression so you can give a song the sound of a particular hardware unit. In other cases, you want to drive the compressor as hard as you can and watch the compressor try to keep up with it. Analog compressors will fight back sometimes and even struggle, and that’s part of their sound too!

Delay

An incredible tool for turning anything into a rhythmic instrument. Adding delay will create multiple repeat copies of an audio signal that can fill out the space or achieve cool effects — and it’s even more powerful if you time the delay to your DAW’s host tempo (most digital delays will do this by default). Most delays also include filtering options (high and low pass); use them to create separation between the original audio and the copies, otherwise it ends up being a tremendous mess! When you want to give delay a try and need a starting place, try dotted eighths — this is typically the setting best optimized for creating a sense of movement. When used properly, delays can turn almost anything into a percussion instrument by repeating it at regular intervals.

Phasing and flanging

Funny enough, these work on the same basic principle as EQ — duplicate the audio signal and add a slight difference in timing / phase. Only this is for a much longer period of time: a few milliseconds, rather than the fractions of milliseconds necessary to create EQ bands. The frequency response created by phasing is really cool — it looks like a sharp-toothed comb (and is also called comb filtering for that reason). Tons of classic rock groups like Led Zeppelin used phasing and flanging frequently to help create their sound.

At the time this was still pretty new, so to stand out today you need to do a little more than just slap on a phasing plugin and call it a day; that’s why you want to combine it with audio effects like distortion to create a complex, composite sound. When balanced appropriately, more plugins are often better than one!

If you want to play with this effect in more detail, try out RETRO’s preset Dual Ring Modulator — listen to what happens when you take this to the max, as it devolves into a trippy, watery sound perfect for recreating classic 70s rock.