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Looking to expand your VST library but short on cash?
Bored of your go-to compressor plugins?
Here are my 6 favourite freeware compressor plugins in 2021.
In Pursuit Of The Best Free Compressor Plugins
The world of dynamic range compression is diverse and complicated.
While EQ is easy to visualize and can be described in a few words, compression comes with more baggage.
Mistakes in dynamics are not always easy to spot and the solutions do not present themselves easily.
Familiarity with compression (and the different types of compressor) is the best way to understand how dynamics can be tamed to perfection and with this collection of free VST compressors you’ll have plenty to work with.
Best Free Compressor VSTs In 2021
The plugins here were chosen for their accessibility and availability, including ease of use and consideration for interface design and presets. Our top 6 free compressor plugins for 2021 are:
As a stripped back, ‘one size fits all’ compressor, DC1A promises to add a touch of magic or a thick layer of grease with just a few tweaks. Though it’s essentially a reduced version of Klanghelm’s DC8C Advanced Compressor, the developer has taken care to ensure it stands on its own as one of the best free compressors with subtle tweaks, a variety of sound and details that make it unique.
Sound and Features
The controls are minimal but full of purpose, DC1A applies a moderate compression ratio that is suitable for a wide range of instruments and sounds.
The bulk of the compression is controlled with the ‘input’ knob rather than a dedicated threshold control or attack and release dials.
This isn’t a limitation, just a different approach that still achieves the same result and some may even prefer it this way as it’s so easy to use.
The four switches along the bottom change the character of the compression in mostly subtle ways.
Klanghelm DC1A Audio Demo
DC1A3 works well as a vocal compressor! Notice in the demo below, how it evens out the volume of the original vocal take in a subtle but pleasing way. On the last two takes, the ‘negative’ switch was engaged to make the louder parts quiet vice versa. Reverb was added before DC1A3 on the final take to exaggerate this effect. Note that the ‘negative’ takes had to have their overall volume increased to match the other takes.
‘Deep’ applies a highpass filter to reduce low-frequency noise and increase the accuracy of the envelope follower (the part of the compressor that measures the signal volume to determine how much compression to apply). ‘Relaxed’ uses RMS detection instead of peak for further accuracy at the expense of response time, making it ideal for slow-moving textures and vocals.
‘Dual mono’ compresses the left and right channels independently so that signals with wide stereo images can breathe easier.
Finally, the ‘Negative’ switch engages negative compression ratios, so that louder sounds are squashed down to be even quieter than the unaffected signal! This can create some interesting ducking effects, encouraging you to drive the audio really hard just to hear what happens.
Negative compression ratios are rarely encountered on other compressors, so DC1A is worth getting for this reason alone even if you’ve already got plenty of other similar plugins.
Billed as a mastering compressor that is “proudly digital” and – shock horror – not an emulation of an existing hardware unit, Kotelnikov is another generous offering from Tokyo Dawn Records that is completely free to download and use.
The focus here is on transparent gain reduction, which is crucial for mastering compression, but there is nothing stopping you from using it for other purposes too.
Sound and Features
Aside from your standard threshold, attack and release functions the Kotelnikov quickly reveals itself to be a swiss army knife of compression.
Rather than being a one trick pony, it is able to easily adapt to a variety of compression scenarios.
Brickwall limiter? No problem.
Need to smooth out a vocal performance? Easily done, just relax the ratio and increase the release time.
Tokyo Dawn Records Kotelnikov Audio Demo
In the demo below, Kotelnikov is applying 6+ db of gain reduction to the second half of this loop. This can be most easily heard on the electric piano part.
Kotelnikov doesn’t add any grit or sauce to the sound and though waveshaping is possible with fractional attack and release time, this isn’t really what it is for at the end of the day.
Surgical, clean and precise compression is what you can expect from this plugin, there are already a wealth of tube compressor VSTs available for those who need more dirt.
TDR deserve a special mention for going the extra mile with the interface here.
Everything is so responsive, there is visual feedback on the controls where possible, showing how the signal is being monitored and how it is reacting to the compression.
The knobs are smooth and precise, there is plenty of resolution in each control and getting precise values with the mouse alone is no problem though they can be typed in if needed.
Overall, Kotelnikov is a no-brainer for anyone who wants to add a professional mixing and mastering tool to their arsenal that can easily be used in a variety of contexts as an alternative to their DAW’s stock plugins.
On the extreme end of compression is limiting, a process that can best be described as compression with a high ratio that is used to ‘brickwall’ the sound, helping to safely trim out rogue peaks and set a ceiling for the output without clipping.
The abuse of this process leads to the ‘loudness wars’, where heavy limiting was used to make songs stand out on the radio and the expense of overall dynamics.
In this context, Frontier by D16 is a military grade weapon that is dangerous in the wrong hands.
Sound and Features
With general use, Frontier makes things as loud as possible without distorting, but there is a ‘soft clip’ switch if you need some subtle harmonics added in.
This plugin is true to the idea that limiters ought to maximize loudness without compromising headroom. The results are seriously huge, the amount of body that can be added to even the wimpiest of drum hits is quite remarkable.
It’s quite possible that D16 have added a fair amount under the hood to shape and treat the signal before and after the limiter. It should be noted that roughly 5ms of latency is introduced when Frontier is active, at least this seems to be the case in Live 10 Suite.
D16 Frontier Audio Demos
Break: Two levels of compression have been applied here, medium and extreme.
Percs: In this demo, you can hear Frontier making these raw junk hits absolutely huge.
Frontier is stripped back when it comes to the controls but the ones provided are essential and should not be ignored. For example, the output volume knob will almost certainly need adjusting unless you’re using it in a mastering chain.
Otherwise, you may be tricked into preferring the louder signal when A/B comparing simply because it sounds bigger.
The interface is fresh, attractive and consistent with other D16 effect plugins, it fits comfortably alongside their other products in both looks and sound.
No compromises have been made just because it is free and it doesn’t function as a ‘lite’ version of a full product that just happens to contain features you can’t live without.
Though you need to make a D16 account before downloading, this is hardly a drawback when you consider what you’re getting, plus you’ll be set up for the future when you will inevitably want to check out more of D16’s awesome plugins!
Finally, a compressor plugin with a horny name! You would be forgiven for thinking Austin Powers has quit the spy game for good to design effect plugins, an unlikely but possible explanation for his mysterious absence (spoiler: he’s probably dead.).
Despite this, this dirty, funky, pumpin’ compressor has as much groove – and subtlety – as the randy man himself.
Sound and Features
Everything here will be familiar to you if you’ve played around with compression enough with the possible exception of the ‘Sensitivity’ knob which is just a basic threshold control.
The real advantage of Rough Rider is the character it lends to the sound, it can really make things slap and slam with no compromises.
Compressors of this build are ideal for adding body and impact to drums though Rough Rider would also be entirely appropriate on a vocal track that needs to be loud and in-your-face, such as a high energy rap verse or screaming in hardcore/metal music.
In fact, anything that needs to be aggressive could benefit from this plugin, it really seems to designed to be loud and proud as opposed to a stealth mastering tool like Kotelnikov.
Audio Damage Rough Rider 2 Audio Demos
For this clip, Rough Rider is used to increase the body of the synth hits and the sustain of the delay tail. In the second clip, we take a look at its parallel compression (mix) function. The first take is dry, the final one is all compressed, and the middle one is a 50/50 blend of the two.
There is a small handful of presets, but any more would mean redundancy with such few controls.
Also included is a handy “copy/paste to clipboard” function that can duplicate settings across multiple copies of Rough Rider in your session.
The updated interface for version 2 looks sleek and crispy, the skeuomorphic attempts at realism in the first version have been abandoned in favor of a no-nonsense minimalist approach which underplays the beastly nature of this plugin.
The window is fully resizable, a feature that is becoming increasingly standardized as screen resolutions in home and professional studios vary more and more.
Rough Rider is available for free from Audio Damage’s website alongside FuzzPlus3, another essential freebie that is definitely worth checking out.
For those unfamiliar with multiband compression, think of it as a combination of EQ and dynamics control.
All the familiar parts of a compressor are here, they’re just strapped to a particular (adjustable) part of the spectrum.
This means you can apply different levels of dynamic control to your bass, midrange and treble, helping you to perfect the dynamic response across various frequency ranges.
This is perfect for drum busses where only the low end of your kick may need fattening up, or in mastering chains for adding that final level of beef before the limiter.
Sound and Features
As mentioned, all the familiar parts of a compressor can be found here, there are just five lots of each control as this is a multi-band compressor.
What’s really special is how Nova uses visual feedback to show you exactly how the compression is being applied to each region.
Nearly anything that can be visualized is visualized and frankly, it is just short of being overwhelming.
This makes Nova much less intimidating for beginners, who will be able to intuitively figure out what it is doing to their audio with sight alone.
Tokyo Dawn Records Nova Audio Demo
Here we’re using just the highest band of Nova with a ratio that is set to expand rather than compress. Notice that it adds a bit of extra snap to the snare sound on the last four hits that makes the first four dry hits sound a bit more plain in comparison.
Another huge help in this area are the mouseover hints that can be enabled by clicking the “?” button in the top right corner of the plugin. TDR deserves major props for going the extra mile on the design elements.
Like the interface, the sound is clean and professional.
The approach here seems to be similar to Kotelnikov, this is not a tool for adding ‘magic’ saturation and grease, rather the goal is transparent dynamic adjustments that add up to a grander representation of the original sound.
It’s worth noting that not all bands need to be engaged at once, they’re just there if you need them.
Two bands would be sufficient for most sound sources, and more bands can then be engaged from there if the sound is active in many frequency ranges.
The ‘wideband’ control is actually a compressor for all the frequencies that aren’t being sent into the other four bands, rather than a compressor for the entire mix.
As with TDR’s Kotelnikov, Nova is a generous full-featured freebie. For those looking to push things even further, a premium “gentleman’s edition” is available featuring 6 bands and extra compression options.
The DCAM is a unique free plugin which features a classic analog console bus compressor design.
The free version is modelled on the DCAM Dynamics suite of compressors. The Freecomp is a great compressor option but its good to know the option for the full suite is there if you need it. The plugin is designed for use on groups and so is great for the mastering process or sculpting a little more character into your bus tracks.
Sound and Features
The Freecomp features DCAM circuit modelling technology and comes with a simple to use interface with standard compressor parameters and is really effective at adding colouration to your sound.
You’ll find this is a flexible compressor as well, whilst the intention is for it to be used as a bus compressor, you’ll be able to easily apply this to individual tracks to tame wild peaks.
This compressor plugin will also be suited to those searching for more extreme compression pumping sounds, particularly producers who focus on EDM. The parameters can be cranked to the extreme to give that favoured ducking effect.
We’re really impressed with this compressor and its great to (even in a free version) have a bit of versatility, variety of sound and be able to apply the compressor to multiple functions. If the Freecomp is up your street then you can upgrade tot the paid suite of compressors which include transient shapers and a limiter.
While some plugins may seem overly simplistic due to a lack of parameters, this is deceptive thinking. Because compressors react very particularly to the volume of the incoming audio, it is highly encouraged that you play around with levels when using plugins with limited controls.
Volume in this context can be seen as an extra parameter, and indeed the most important one when it comes to compression.
Because each plugin in this list has its own particular advantages and disadvantages in different situations, the safest bet is to grab the whole lot and figure out when and how to use them simply by experimenting and building familiarity. After all, they are free, so what do you have to lose?