PLUGIN WEEK 2025: When we think of desirable compression plugins our attention often turns to rare flavour-filled hardware emulations. Good examples would be valve designs based on the Fairchild 670 or opto designs based on the Teletronix LA-2A. However, when it comes to flexibility, well designed VCA compressors always win hands down.
Here I’ve picked 5 of my favourites and I’m going to explain what they do and why I particularly like them.
As we’ll discover, each is good at certain tasks, although there is overlap. Though many of the outcomes can be achieved by more general purpose digital compressors, a quick application of any of the following will just get you there more quickly.
1. IK Multimedia Comprexxor (Empirical Labs Distressor)
When Empirical Labs launched the Distressor hardware it became an instant hit seemingly because of its ability to create lively FET style compression and also its famous ‘Nuke’ high ratio setting. But as a design it offers so much more than this, and if there’s one classic VCA design you want in your plugin toolkit, then this is it.
Its fundamental remit is to deliver different classic compression styles using a VCA circuit, with this clean controllable design putting the user in total control. In fact, it’s tuned to offer everything from opto style squashiness to FET style superfast attack, with each of the 8 ratio settings delivering its own compression onset style. This is then coupled with 2nd and 3rd harmonic distortion options, a choice of side chain detector settings and wet/dry mix.
There are a few plugin emulations of this classic, including UAD-2’s official EL8.
I particularly like Comprexxor from IK Multimedia, though, which enhances the original with some excellent features. These include GB Mode, which emulates the ‘all button’ option on the Urei 1176, and an Optical macro, which quickly switches the unit to Ratio 10:1, Attack 10 and Release 0 - the settings used for optical style compression.
2. Cytomic The Glue (SSL Mix Compressor)
SSL’s mix compressor is a modern classic that has remained a key component of their hardware design for years, and although recent hardware versions are more flexible, the core design has always remained roughly the same.
In plugin form a similar thing has happened, with added software flexibility such as side chain tweaking and wider ratio settings both common additions to the core parameters.
But why is the design so popular?
Ultimately it’s because it delivers, and in more ways than one. So if you’re working towards a punchy mix then the 4:1 ratio coupled with a medium/slow (10ms) attack and fast release (100ms) is in order.
Meanwhile, if you’re after something more gentle then the 2:1 ratio with its inherent soft knee shape is the way to go. Try coupling this with a medium attack and Auto release. In both cases adjust the threshold for just a few dB of gain reduction and your mix will sound more cohesive.
There are lots of excellent plugin emulations, with options from many big developers such as Waves, Softube and SSL themselves.
But one of my favourites comes from Cytomic. The Glue is a straight up plugin emulation that not only captures the essence of the original design, but also offers adjustable side chain filtering, internal and external side chain options, compression range and peak clipping.
3. UAD-2 dbx 160 ( DBX 160 Compressor/Limiter)
Dbx and more specifically its founder David Blackmer are key to the VCA compression story, as it was Blackmer that invented a VCA design suitable, and quiet enough for the task.
Indeed Blackmer’s design is what you’ll find in each channel of the original SSL E Series desk - the so-called ‘gold can’ VCA - and this same concept features in his own dbx 160 compressor model.
The 160 range went on to include a number of versions, including the dbx 165 with its ‘over easy’ option. However, the original (and simplest) model, the dbx 160 (often called the VU model) is still a great one trick pony compressor.
It has a hard knee onset and very simple controls - Threshold, Ratio (1.5:1 up to 20:1) and Output Gain. Its particular skill is hitting transient heavy sounds such as snares, acoustic guitar or electric bass to help fatten the sound.
My favourite plugin version is UAD-2 dbx 160 as it’s incredibly close sonically to the hardware.
However, other worthy options include Waves dbx 160 and Softube’s VCA Compressor amongst others.
To get started set the metering to Gain Change and adjust the threshold to get a couple of dB of GR on peaks - the actual gain reduction will be greater. You’ll know if you’ve over done it as it will sound way too squashy and undefined.
4. Waves API-2500 (API 2500 Bus Compressor)
API’s stereo VCA compressor may not have quite the same profile as SSL’s mix compressor, but it’s an excellent and highly flexible design that has many fans.
Perfect for stereo duties such as the mix bus or stereo sub groups, it’s also great for other stereo sources such as drum overheads or acoustic piano, which it seems to have an uncanny ability to smooth out.
Although it’s a stereo unit, this shouldn't deter you from trying it on mono sources such as vocals and bass.
The number of controls and settings can be a bit daunting at first, so it’s worth explaining a few of the specifics. First up the design includes 2 distinct topologies - feed back and feed forward - that allow both smooth vintage outcomes (FB) and harder modern outcomes (FF).
Next up, there’s a Thrust circuit, with 2 tailored settings (Medium and Loud). These change the shape of the side chain, influencing how the compressor responds. Finally, by default the design has automatic gain make up. This helps with A/B bypass comparison but can also be bypassed using the Manual Make-up button.
There aren’t loads of API-2500 plugin versions, but worthy options are the UAD-2 API 2500 bus Compressor and Waves API 2500 Compressor, which is my preferred choice.
5. SSL LMC+ (SSL Listen Mic Compressor)
Yes it’s another design from SSL, but this characterful compressor has been a popular tool ever since hardware desk users started tapping into the circuit so they could use it as an insert. Designed as a limiter circuit to help level out the talkback mic option on the desk and make the talkback more intelligible, users soon discovered they actually quite liked what it was doing, particularly to the loud live room sounds that were coming down their talkback mic.
SSL created their first LMC-1 plugin for fun and gave it away for free, and much like the original design it was very basic.
The latest incarnation, LMC+, is a very different offering and adds in a bunch of extra features to help you add big time flavour to your audio.
Options include high and low pass filters, external side chain, optional auto gain make up and dry/wet mix. Two additional settings, Scoop and Split, make further changes to the wet and dry signal respectively.
LMC+ is probably the least flexible VCA compressor you’ll ever own. However, it’s great for squeezing energy out of lacklustre ambient sounds, and if you regularly mix acoustic drums is a must have tool.
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