ZL Audio has released a freeware compressor plugin called ZL Compressor, available for Windows, Linux, and macOS.
We’ve already covered ZL Equalizer, a powerful dynamic EQ plugin from the same developer, so it’s interesting to see what they came up with in the realm of compressors.
ZL Compressor has four different operating modes:
- Clean: Modern, transparent VCA style compression
- Classic: Feedback compression with a FET-style character
- Optical: Inspired by the smooth and musically sounding pieces of light-sensitive gear we all wished we had
- Vocal: Compression mode developed specifically to enhance and control vocal tracks
The plugin also has an advanced side chain functionality that lets you control the side chain signal with an eight-band EQ.
This provides lots of possibilities for sound shaping with frequency-specific compression. Make the plugin react more or less to certain parts of your sound without introducing unnecessary artifacts.
This is a nice feature for both creative sound design and surgical mixing tasks alike.
Furthermore, ZL Audio has implemented up to 8 times oversampling to minimize nasty aliasing artifacts, even at unorthodox and extreme compression settings.
The developer claims that the plugin is CPU-friendly, so you should be able to load up several instances without experiencing sluggish performance. The oversampling control can be found in the top right corner.
Please note: the developer warns against automating the oversampling amount, as it could induce momentary clicks and pops.
Next to the oversampling control, you can dial in lookahead for the compressor. This comes in handy on complex program material, if you need to catch fast transients, for instance.
The UI looks nice and clean, with an appealing UI that shows both RMS and Peaks levels. You can change the timing of the analyzer to fit your needs, too. The analyzer section is also the place where you apply EQ to the side chain.
The bottom of the plugin has your standard controls like threshold, ratio attack, release and make-up and knee, and curve parameters to influence the transfer curve and non-linearity of the processing.
To knobs labelled “pump” and “smooth” adjusts the behavior even more. Pump makes the attack more aggressive and gives you a typical pumping effect, while Smooth relaxes the start of the release stage.
In short: even more dynamic control!
ZL Compressor is a proper dynamics workstation, but fear not if it sounds complicated. The UI is pretty straightforward forward and applying standard compression should be easy.
For the more advanced functionality, I recommend checking out the manual provided by ZL Audio.
The plugin is still in pre-release, but I personally haven’t encountered any bugs thus far.
In my experience, ZL Audio always delivers quality. If you haven’t already, check out the powerful ZL Equalizer or the ZL Warm saturation unit while you’re at it! All free, of course.
ZL Compressor works with Windows, macOS, and Linux.
Download: ZL Compressor (FREE)
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Last Updated on June 26, 2025 by Tomislav Zlatic.
