Sidechaining is one of the most popular mixing techniques in modern music, and though it’s easily heard in some forms of electronic music because of its distinctive "pumping" effect, it can be just as useful for cleaning up tracks and creating space and separation. 

Many new compressor plugins come with built-in sidechain features, which is pretty much all you need to use the effect to its fullest. However, a lot of these plugins cost quite a bit. If you’re looking to save some cash and utilize an expert technique like sidechain compression in your mixes, we’ve compiled a list of the top 13 free sidechain VST plugins on the market today.

What Is Sidechain Compression?

Sidechain compression is a technique or effect designed to lower the volume of an audio signal in response to another incoming audio signal, otherwise known as the sidechain input. This gain reduction or compression will only occur when the incoming audio signal is active.

Let’s say you have a kick and bass that are both taking up low-end space in your mix, though you don’t want to rip the low-end out of either of them using EQ. You can allow both of them to take up that space by applying a sidechain compressor to the bass track, so that every time the kick comes in, the volume of the bass ducks out for just a split second. 

There are many ways to use sidechain compression to let multiple tracks co-exist in a mix together, and with the following free sidechain VST plugins, you can do it all without dropping a dime!

1. TAL-Filter-2

TAL-Filter-2 is not your average free sidechain plugin. Instead, it's a host-synced filter module that uses a wide range of unique filter types, volume modulation options, and panorama effects. I highly recommend this plugin for those who want to implement trance gate or tremolo effects into their mixes.

Of course, the panning option is great, too, as it can be used to automate the movement of percussion from left to right in the stereo field to make it more interesting. 

There are plenty of cutoff filters that you can use as well, including the super clean SVF filter, which uses self oscillation and a diode clipper in the feedback track. As with many TAL plugins, the interface is sleek and modern, making it just as pleasing to look at as it functions.

2. Flux Mini 2

Flux Mini 2 is similar to the TAL plugin above in that it goes beyond your standard sidechain compression. It’s a highly versatile audio effect that can add dynamics and character to your tracks, using the integrated and completely customizable graph that shapes the incoming audio using amplitude modulation, resonance, and filter cutoff. 

You can draw your own modulation shapes on the graphical interface, setting your desired depth with the slide just beneath the set of parameters to listen to your custom rhythmic effects take place in real time.

There are 20 presets to choose from, which offer great jumping-off points as you’re getting used to the plugin. Plus, there are plenty of shapes that you can flip through to experiment with different styles of sidechaining. 

You’ll also find both low-pass and high-pass filters in the sidechain functionality, expanding the creative possibilities for all your sidechaining needs. For a little bit of added excitement, you have the resonance control, which you can use to get experimental. I like to fiddle with the resonance settings on this plugin and resample it numerous times through different effects chains as well. 

One of the best things about this plugin is how precise you can get with the shapes, thanks to the gridlock interface, which makes drawing and aligning the compression with your beat easier than ever.

Overall, it’s a fantastic, user-friendly free plugin, with a solid user interface and tons of flexibility.

3. Sidechainer2 RDG Audio

Sidechainer 2 might be one of my favorite free sidechain VST plugins on the market today that’s designed explicitly for sidechaining and ducking effects. 

The interface is super user-friendly, making it incredibly easy to use, even if you’re brand new to sidechaining. It’s even easier to draw custom shapes to sidechain your audio in unique ways.

With a mixture of beat sync rate and volume automation, which you can use to align your custom envelope with the BPM of your DAW, Sidechainer 2 makes creating compelling sidechain pumping effects seamless.

Even beyond its functional uses, it’s an excellent piece of software for creative sound design. I like to use it after spatial effects plugins, such as delay and reverb, to get them out of the way of vocals and other instruments when I want to keep my mixes clean yet exciting.

4. Ableton Live Sidechain

I’ve used pretty much all of the major DAWs, and though most all of them have sidechain VST options, Ableton Live's native sidechain functionality is one of my favorites to use. Plus, since it comes free with Ableton, there’s no need for an external third-party plugin! 

It has an incredibly user-friendly design with Ableton’s minimalist aesthetic, and the sidechain feature gives you plenty of different parameters to mess around with to dial in the perfect amount of gain reduction for you mix. 

The plugin delivers real-time feedback as well, so you can see exactly how your settings are impacting your mix.

If you're not an Ableton Live user, you can use this sidechain compressor plugin in other DAWs with ReWire.

5. MeldaProduction MCompressor

MeldaProduction’s free M-Compressor plugin is an incredibly feature-rich plugin considering the fact that it’s free.

It offers adjustable sidechain compression shapes, allowing you to craft dynamic sound and volume effects, as well as offering visual representation of the compression process on the high-quality graphic display, so you can see your adjustments in real-time. 

It’s a wonderful option for beginners, as you get a visual representation of parameters that can otherwise be hard to hear, such as threshold, ratio, attack, and release. 

When you throw the sidechain on, you can use the high-pass and low-pass pre-filters for better control over your effect, which can be particularly useful in situations such as drum bus processing, where you want to avoid pumping every time the kick hits. 

MeldaProduction offers its entire MFreeBundle along with this compression plugin, too, so you can enjoy a whole suite of effects!

6. DualComp

DualComp is an old-school free compressor utility plugin that offers a surprisingly warm and unique sound. Beyond the regular compression algorithm, it offers excellent sidechaining compression capabilities.

The sidechain curve is nice and smooth on this particular plugin, which is great for subtler forms of sidechain compression, especially when you want to make space for multiple instruments in your mix without it sounding too obvious. 

The plugin isn’t available on the Teragon Audio website any longer, as they stopped developing updates, but you can still find it for Windows and Max OSX on various websites if you search for it.

7. Martin Eastwood Compressive Pro

Martin Eastwood Compressive might not be the prettiest looking plugin out there, but it’s one of the best free sidechain compression VST plugins around, especially for those who do not have tons of CPU power to spare. 

It’s modeled after a vintage analog RMS compressor and uses a smooth sidechain algorithm with a three-band EQ and mid/side controls, giving you total control over the way your compressor reacts to the input signal. 

On the bottom of the plugin, there's even a handy little mix knob, so you can dial in parallel compression, perfect for when you want dynamic consistency without squashing your sound.

Note that they also have a Compressive Lite version, which uses the very same algorithm as the Compressive Pro plugin, though with less CPU, making it even friendlier on older systems.

8. Platinumears FL4TT3RY

FL4TT3RY is the next compressor plugin on our list, which offers gentle compression and sidechaining, perfect for use in more natural styles of music and on mix or instrument busses. The look reminds me a lot of the 1176 plugin, though it sounds a lot less aggressive. Even so, it has a bit of a hardware sound, which is nice if you don’t need something totally transparent. 

The compression algorithm uses a soft knee and RMS level detection that changes the way the compressor works based on the attack time. The envelope shaping is incredibly powerful, and it even comes with a switchable high-pass filter to keep low-end energy from impacting the gain reduction. 

Lastly, the plugin uses asymmetric soft clipping to prevent unwanted overs, a neat little feature for a zero-latency, low-CPU digital compressor.

9. Vladg/Sound Molot

If you’re in the market for a transparent sidechain compressor plugin, the VladG Molot Compressor is not it. This analog-modeled compression VST adds tons of color to the sound, perfect if you want a bit of analog warmth in your mix. 

The GUI can be a bit intimidating, as there are tons of controls to choose from. However, the more you use it, the more you’ll realize how much fun it can be. I like the fact that it adds a bit of saturation to my audio when I push the input signal, and the VU gain reduction meter is helpful to see how hard you’re pushing your compression in real time. 

I would go as far as saying that the VladG Molot Compressor is one of the most versatile VSTs on this list, perfect for the tinkerers out there.

10. Cockos ReaComp

Cockos’ ReaComp is one of the most configurable free compressors out there. The interface is a bit outdated, though if transparent control is what you’re after, it’s a mean piece of software. I find myself using this plugin when I want to duck my bass out of the way in the cleanest way possible.

You’ll find plenty of parameters to fiddle around with, including different feedback compression modes, oversampling, sidechain filters, and the program-dependent auto-release mode. The entire compressor can be dialed in parallel using the wet/dry mix knob, and with its low-CPU design, you can use it on just about any system without tanking your session.

As of now, Cockos ReaComp is only available on Windows.

11. Slim Slow Slider Side Chain Compressor

The Side Chain Compressor plugin from Slim Slow Slider might be one of the most basic sidechain compressor options on this list. The interface is super straightforward, offering seven knobs with expected compressor controls, including threshold, ratio, attack, release, gain, hold, and volume. 

There’s even a small slider at the bottom that you can use to variably shift the knee from soft to hard. On the top, there’s a small GR meter to give you a visual representation of how much sidechaining you’re doing.

You can use the plugin in both mono and stereo modes, whether in Mac OSX or Windows systems.

12. Christian Budde - Lightweight Multiband Compressor

Last on our list, we have the Lightweight Multiband Compressor from Christian Budde, which is a soft-knee compressor with tons of controls for absolute dominance over your standard compression and sidechaining. 

The plugin uses second-order linkwitz-riley crossover filters, offering a flat cutoff at the frequency filter. This offers a super consistent sound from band to band. 

Though you don’t have a real-time frequency analyzer on the interface like you do on higher-end multiband compression plugins, the layout is super effective, making it easy to dial in the perfect settings for each band.

Final Thoughts

There you have it, the best free sidechain plugins on the market today. The best thing about these freeware sidechain compressors is that there's no risk to download and try them all out. Whether you make modern electronic music or you just want an extra tool to integrate dynamic sound effects into your mixing process, the free plugins above will help you achieve desired results quickly!

Have fun!