How to Use Sidechain Compression in Your DAW (and Why You Should)

Sidechain compression adds clarity to your mix, preventing a track from being drowned out by other instruments. And setting it up in your DAW is easy.

Sidechain compression is an audio signal compression technique that has become famous for its use in electronic dance music (EDM) and modern pop music. This form of compression is often heard as a pumping effect matching the hits of a kick drum, but its utility goes well beyond this sonic effect.

We'll go over how to set up sidechain compression alongside several potential uses that can help add definition, dynamism, and distinction to your audio.

You may recognize and implement sidechain compression for its signature pumping effect. However, the main reason it was developed is to resolve frequency masking issues. This typically occurs when two instruments occupy the same space in the frequency spectrum. Given that they emit similar frequencies, one instrument can easily drown out the other.

Another tool you can use to fix frequency masking issues is an equalizer (EQ). Learn how to use EQs and filter sweeps to better carve out space for all the audio elements in your mix.

What separates sidechain compression from EQ edits to fix frequency masking is that it can offer you additional excitement, energy, and rhythmic emphasis.

It's for this reason that a variety of genres use sidechain compression to accentuate a core element of their groove—the kick drum—and make their respective bass parts duck out when the kick drum hits. In this manner, the kick drum isn't overshadowed by other instruments that play in the same frequency range.

This form of compression is, of course, not limited to use on kick drums and bass parts, but we'll go through some compression basics and how to set it up before we cover other potential uses.

Compression primarily serves to reduce the dynamic range of your audio. This means that it decreases the difference between its softest and loudest parts. Thus, the softest parts become louder, and vice versa.

What compression affects is the volume envelope (how a sound starts, continues, and ends) of your selected tracks, bus, or mix. Compression only begins when the decibel (dB) level of your input signal goes above the threshold value. Before you jump into sidechain compression, it's important to learn how to use all compression parameters, so you can get the most out of different compression techniques.

Each compressor type varies in terms of how much sonic coloration they impart to the selected audio. Some deliver transparent compression (without imparting sonic color), and others add distinct sonic flavors to the audio. Make sure you know about the different types of compressors to help you choose the right one for your audio.

Sidechain compression works by placing a compressor on the instrument you want to duck down (e.g. Bass Synth 1). Then, you change the input signal to match the instrument you want to highlight (e.g. Kick Drum 1).

You can see this option in stock Logic Pro (and most DAW) compressors in the top-right. The result is Bass Synth 1 rapidly compressing and ducking down whenever your Kick Drum 1 plays.

This varies from regular compression, as normally, the input signal will be the audio or MIDI track that you want to compress. In other words, the input signal of the compressor on your Guitar 1 track will be your Guitar 1 track.

Sidechain compression usually requires a rapid attack time, a threshold value that suits the dB level of your audio, and a release time that matches the rhythmic characteristics of your audio. For example, fast-paced musical works will require fast release times, and vice versa.

There are a variety of ways you can use sidechain compression, and not all of them are limited to musical productions. We'll cover a few, but don't forget to experiment widely with sidechain compression in diverse audio contexts.

In certain audio-related projects, scripted or free-flowing speech may be the focus. Typically, some kind of music will be playing in the background. Sidechain compression allows you to add further clarity to spoken audio by compressing the background music precisely when speech is occurring.

All you have to do is place a compressor on the background music, and select your spoken audio track as the sidechain input signal.

While we've covered a common frequency masking issue between the kick drum and bass parts, the same problem often occurs with instruments higher up in the frequency spectrum.

One such issue is the frequency overlap between lead vocals and bright guitars. Once again, sidechain compression lets you maintain focus on the lead vocals without drastically impacting your guitars (which may be a central part after the vocals).

For additional control, place a multiband compressor, rather than a normal compressor, on your bright guitar tracks. This will allow you to compress certain frequency ranges (e.g. 2–7 kHz) and leave the lower frequencies intact. Then, set your vocals as the sidechain input, and you're good to go.

Another problem you can encounter with vocals is a lack of clarity when you add some necessary reverb. Rather than toning the reverb down universally, you can use sidechain compression so that when the vocal line is playing, the reverb ducks down. As soon as the vocal line finishes, the reverb resounds to its fullest.

To set this up, use a send on the lead vocal, and place a reverb plugin on the resultant aux channel. Then, place a compressor below the reverb plugin. Select your lead vocal as the sidechain input, and adjust your reverb's compression parameters to taste.

You can also fine-tune and vary your reverb intensity and settings in real-time when you learn to use automation in your DAW. Do so, and you can maximize your use of all your audio production tools.

Whether you want to add a pumping effect and excitement to your mix or just want better audio definition, sidechain compression is a valuable tool.

Make the most of the sidechain input feature in the stock compressors of your DAW. Emphasize your kick drum in the balance of your mix by using sidechain compression on your bass parts. Apply the same strategy to highlight your main spoken or sung vocals. Doing so will take the balance of your audio to another level.

Bill has 14 years or so of experience as a professional musician playing a few stringed instruments. He has since branched into music production and composition for the last 6 years to play not only a few, but all the instruments. When he's not musicking or writing, you'll find Bill farming.