Artist Media Studio just released their CPT-100 Mastering Compressor for free.
Before we dive into the details, please note that this plugin is only compatible with VST2 plugin hosts on Windows. If you use macOS or Linux, feel free to raise your fists and shout at the clouds.
If you need a free mastering compressor, you can also check out the much-loved Fircomp 2 by Jon V Audio or the legendary Kotelnikov by Tokyo Dawn Labs.
However, I digress; the CPT-100 is intended to be a relatively transparent and easy-to-use plugin, inspired by hardware units that employ typical FET-style compression.

It’s supposed to be a cleaner (and free!) alternative to the tube-based CPR-100 by the same developer, which is being released soon as a paid product.
CPT-100 boasts all the parameters you might expect from a standard compression unit.
You set it up by dialing in your threshold (from -25 to -0 dB), ratio (from 1:1 to 10:1), and attack and release settings.
In addition, CPT-100 has three different detection modes for more advanced tweaking: PEAK, AVG, and SUM.
PEAK reads the loudest signal of both channels, AVG reads the average signal of both channels, while SUM reads the sum of both channels.
This can significantly change how the unit behaves and helps you dial in your desired compression flavor to suit the material at hand.
CPT-100 includes a useful low-pass filter in the internal sidechain/detection circuit.
A common problem with compression, especially at the mixbus level, is uncontrolled bass, kicks or sustained low end energy making the compressor crap out and distort while flattening your mix in an undesirable way.
Such a low-pass filter lets you control the amount of low-frequency data the compressor reacts to. This can help you attain both punch, clarity, and more natural dynamics, as well as set your track up for further processing.
CPT-100 has sliders for input and output volume as well as makeup gain plus a dry/wet knob.
Control the amount of color from the FET-inspired compressor by pushing the input volume and the back of the wet amount to reach a classic parallel compression effect that beefs up the body of your sound while letting the transients of the input source pass through unharmed.
The plugin also features meters for input, gain reduction, and output, respectively, allowing the user to easily gauge what is happening.
We all like to think we know what compression sounds like, yet nothing beats looking at a flashy gain reduction meter at every opportunity, thinking that we’re decent mixing engineers. Such is life.
Download: CPT-100 (FREE)
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Last Updated on June 6, 2025 by Tomislav Zlatic.