Create Better Mixes: Sidechain Compression Explained

Sidechain compression is a production technique you might have encountered in modern music mixing. 

At its core, it's used to create a relationship between two audio signals, allowing one signal to influence the volume of another. This is a powerful tool in your production arsenal for managing how different elements of your mix interact with each other. 

By linking, or sidechaining, say, your kick drum to the bass line, you can make sure that every time the kick hits, the bass temporarily ducks out of the way, creating space for the kick and a rhythmic pulse that can help make your track groove.

As you start experimenting with various uses of sidechaining, you'll find that it extends beyond merely avoiding frequency clashes. It's a creative tool that can add a distinct dynamic to your music, be it in electronic dance music, where it's commonly used to make the kick drum stand out, or in more subtle applications like creating space for vocals in a busy mix. 

Soundtrap’s Sidechain Compression tool is an effective and simple way to create interesting dynamics in your tracks. It’s perfect for adding the pumping effect to certain instruments and ducking the notes of your beat.

It's all about shaping the energy and flow of your track, and when used skillfully, it can elevate the overall sound of your mix.

Learning to use the technique doesn’t only involve understanding the theory; it's about practical application. Setting up a sidechain typically involves choosing your key input, the trigger, and the track that will be affected. 

Parameters like threshold, attack, release, and ratio allow you to dictate how and when the effect kicks in. 

Experimenting with these settings can lead to a wide range of sonic possibilities, making sidechain compression a technique well worth mastering

Fundamentals of Sidechain Compression

Understanding the concept of sidechain compression can give your mixes a professional edge. This technique can be pivotal in managing dynamic range and ensuring elements of your mix stand out as intended.

What Is Sidechain Compression?

Sidechain compression is a form of dynamic range compression triggered by an external audio signal. 

Typically, when you apply compression to an audio signal, the aim is to reduce its dynamic range, the difference between the loudest and quietest parts of the signal. 

With sidechain compression, the compressor is not activated by the loudness of the signal it's compressing (the target signal). Instead, it responds to the loudness of a separate audio signal (the sidechain input signal). 

This means that gain reduction (lowering the volume) is applied to the target signal when the sidechain input signal exceeds a certain signal level, causing the target signal to duck or diminish in volume temporarily.

• Sidechain input signal: The external signal that triggers compression.

• Target signal: The audio signal that is being compressed.

• Gain reduction: The amount by which the audio signal is reduced in volume.

• Dynamic range: The difference between the loudest and softest parts of the audio signal.

Understanding the Signal Chain

When setting up sidechain compression, you need to understand the flow of your signals:

1. Input signal: Identify the audio you want to affect with compression – this will be your target signal.

2. Sidechain input: Choose the audio signal that will act as the trigger for compression – your sidechain input signal.

3. Attack time: Adjust how quickly the compressor reacts to the sidechain input signal exceeding the threshold.

4. Release time: Decide how soon the compression effect stops after the sidechain input signal falls below the threshold.

Adjusting the attack and release times will shape how naturally the gain reduction feels. 

Quick attack times can lead to a very responsive compression, ideal for certain rhythmic effects, while longer attack times allow some initial transients through, maintaining some of the natural dynamics of the target signal. 

Release time will affect how quickly your sound returns to its original level, which should be set according to the tempo and rhythm of your music to ensure the effect gels with the groove.

By thoughtfully setting these parameters, you can successfully manage the interplay between your musical elements, enabling a cleaner, more focused mix.

Sidechain Techniques in Music Production

Sidechain compression is more than just an effect—it's a vital tool that can shape the very heart of a mix, particularly in electronic music genres. It can be employed to create that characteristic pulse in a track or to ensure clarity between competing elements.

Utilizing Sidechain in Electronic Music

Famous artists like Daft Punk and Eric Prydz are known for using this technique to create space in their mixes. 

Here's how you can set this up in your DAW:

1. Identify your trigger source: Usually the kick drum.

2. Choose your target audio track: This could be your bassline or lead synth.

3. Add a compressor to the target track.

4. Configure the compressor to respond to the kick drum signal (sidechain input).

5. Adjust the threshold, ratio, attack, and release settings to taste.

Achieving the Classic Pumping Effect

The pumping effect is synonymous with house music and is used in countless dance tracks to create a rhythmic feel that aligns with the dance floor's energy. To achieve this effect:

• Use a fast attack to let the compressor quickly clamp down on your bass or synth track.

• Set a moderate to high ratio to ensure a noticeable gain reduction.

• Adjust the release time so that it creates a rhythm in conjunction with the tempo of your track—the compressed audio should bounce back in volume before the next kick hits.

Keep in mind that overusing sidechain compression can lead to a mix that feels unnaturally suffocated. Don't be afraid to experiment and tweak the settings carefully to find the right balance for your particular track.

Read more: Introducing Instant Sidechain: The Secret Sauce Behind Radio-Ready Music

Essential Tools for Sidechain Compression

Choosing the Right Compressor

Regular Compressor Plugins

• Look for a compressor plugin that offers a dedicated external sidechain input to achieve more control over your sidechain source.

Multiband Compressor

• Consider a multiband compressor for applying sidechain compression to specific frequency ranges without affecting the entire mix.

Configuring the Compressor Settings

• Threshold: Set this level to determine when the compression begins based on the input from the sidechain source.

• Ratio: Decide how much compression is applied once the threshold is exceeded.

• Attack/Release: Adjust these to control the responsiveness of the compressor to the sidechain signal.

• Sidechain Input of a Compressor: Pay attention to the signal you route into the sidechain. Use a high pass filter if necessary to focus on high-energy elements like the kick drum.

Internal Sidechain Filters

These can help you refine which frequencies trigger the compressor:

• High Pass Filter: A high pass filter within the sidechain path can ignore low frequencies, reducing the trigger from bass-heavy elements.

• Detection Circuit: Choose between peak and RMS detection to match the compressor's response to the dynamic nature of your sidechain input.

Understanding and utilizing these tools effectively will give you control of the dynamic relationship between tracks, ensuring each element sits perfectly within your mix.

Essential Tools for Sidechain Compression

Choosing the Right Compressor

Regular Compressor Plugins

• Look for a compressor plugin that offers a dedicated external sidechain input to achieve more control over your sidechain source.

Multiband Compressor

• Consider a multiband compressor for applying sidechain compression to specific frequency ranges without affecting the entire mix.

Configuring the Compressor Settings

• Threshold: Set this level to determine when the compression begins based on the input from the sidechain source.

• Ratio: Decide how much compression is applied once the threshold is exceeded.

• Attack/Release: Adjust these to control the responsiveness of the compressor to the sidechain signal.

• Sidechain Input of a Compressor: Pay attention to the signal you route into the sidechain. Use a high pass filter if necessary to focus on high-energy elements like the kick drum.

Internal Sidechain Filters

These can help you refine which frequencies trigger the compressor:

• High Pass Filter: A high pass filter within the sidechain path can ignore low frequencies, reducing the trigger from bass-heavy elements.

• Detection Circuit: Choose between peak and RMS detection to match the compressor's response to the dynamic nature of your sidechain input.

Understanding and utilizing these tools effectively will give you control of the dynamic relationship between tracks, ensuring each element sits perfectly within your mix.

Sidechain Applications and Creative Uses

Sidechain techniques are not just for the tech-savvy; they can enhance your music production by creating dynamic changes in volume and space within a mix. Learn how you can use sidechain compression for a more vibrant sound.

Sidechain for Dynamic Bass Levels

Sidechain compression should be one of your go-to tools when you want your bass track and kick track to sit well together in a mix. It works by lowering the volume of the bass track whenever the kick track hits, creating that pulsating effect that's essential in electronic dance music (EDM). 

Here's how you can achieve this:

1. Insert a compressor onto your bass track.

2. Route your kick track to the compressor's sidechain input.

3. Adjust the threshold to determine when the bass level dips.

4. Set the release to control how fast the volume returns to normal after the kick hits.

The result? Your bass line pumps in rhythm with the kick, giving your track that professional polish and pulsing energy.

Creating Space with Sidechain

Sidechaining can also be used to introduce creative space within your mix. Imagine you have a bass guitar laying down a groove, and you want to accentuate its rhythmic element without overpowering the mix. 

You can use sidechain techniques with audio effects to achieve this. For example:

• Apply a high-pass filter to a synth pad and sidechain it to the bass guitar. It will cut the frequencies whenever the bass notes hit, allowing the bass to stand out.

• Use sidechain compression on reverb or delay sends to duck the effects when specific instruments play, creating a clearer mix.

By astutely applying sidechain routing, you have the power to manipulate the spatial dynamics of your song, allowing the key elements of your mix—like a bouncing bass line—to shine through without constant manual volume automation.

Advanced Sidechain Techniques

Multiband Sidechain for Frequency Precision

If you're aiming to avoid collateral impact on unintended frequencies, multiband sidechain compression is your go-to technique. It lets you apply compression to a selected frequency band. 

For instance, when the kick drum hits, you can have the compressor duck the bass level only in the low end, preserving the higher frequencies of your bass line. 

The steps are straightforward:

1. Use a multiband compressor to split your bass (or other target track) into frequency bands.

2. Apply sidechain compression only to the lower frequencies.

3. Adjust the threshold and ratio to ensure the bass ducks are in rhythm with the kick drum without affecting the rest of the frequency spectrum.

By doing so, you maintain the integrity of the entire track, keeping the mix clean and balanced.

Enhancing Sidechain with Automation

You can get creative with automation to add dynamic movement to your whole mix. You're not limited to standard threshold and release parameters. 

Here's how you can utilize automation with sidechain compression:

• Automate the sidechain input level to change how much the bass level is reduced at different points in your track.

• Adjust the sidechain attack and release values during transitions to create tension and release.

• Use automation to turn sidechain compression on and off for different sections of your track, providing variety and maintaining interest throughout your arrangement.

These techniques are tools to help you control the dynamics of your mix with precision and flexibility. Use them thoughtfully to ensure that every element sits perfectly in the sonic landscape of your music production.

Conclusion

Sidechain compression is a versatile tool with a wide range of applications in music production. 

Whether you're shaping the dynamics of a dance track or enhancing the clarity of lead vocals, understanding how to utilize sidechain compression effectively can take your mixes to the next level. 

By mastering the intricacies of sidechain routing, adjusting compressor settings with precision, and exploring creative uses such as dynamic bass ducking and spatial manipulation, you can unlock the full potential of this technique. 

With the right approach and enough experimentation, sidechain compression becomes not just a technical process but a creative expression, enriching the texture and energy of your music.

About the author

Tero Potila is a professional music composer and producer. His career combining knowledge and experience from music, TV, film, ad, and game industries gives him a unique perspective that he shares through posts on teropotila.com.