SmackLabs Releases Free SL63x Compressor VST Plugin


SmackLabshas released SL63x, a freeware compressor effect in 32-bit VST plugin format for Windows-based digital audio workstations.

SL63x appears to be based on a DBX type compressor, designed for quick and easy dynamics processing. The developer has decided to go with a rather minimal set of controls, only including input and output gain parameters, along with a horizontal slider that appears to control the ratio.

The slider’s value can be adjusted freely, meaning the user can dial in exactly the ratio they want instead of being locked to 2:1, 4:1. etc. When the slider is positioned all the way to the right, SL63X should function essentially as a limiter. Since there is no “threshold” control on this particular plugin (it’s at a fixed point), you’ll need to adjust the input level and keep an eye on the gain reduction meter in order to fine tune the signal to the compressor’s sweet spot.

I would rather have full control over the compressor that I’m working with and prefer the 1176 type compressor layouts. However, in certain cases, I could see myself going for something more simple like this if I am using it more subtly, and especially if I enjoy the specific coloring effect of that particular unit.

SmackLabs describes the SL63X as having a “soft knee at low and moderate levels”. This may help the compression sound a bit more natural and less apparent. I haven’t yet heard this compressor in action, but if I had a Windows system, I would definitely experiment with it. Currently, it is only available for 32-bit VST plugin hosts on Windows, as it appears to have been developed using SynthEdit or FlowStone. Thankfully, visitors are not required to register on the developer’s website in order to download the plugin.

SL63x is available for free download via SmackLabs (2.07 MB download size, DLL file, 32-bit VST plugin format for Windows).

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About The Author

Ben Bishop is a music producer based out of Nashville, TN. He works with many local artists in the pop/indie world and has a recording studio in East Nashville.


  1. It’s okay I guess. Don’t think it will be anybody’s go-to compressor or limiter but you never know, it just might be the right flavour for someone out there.

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