Stemwire has released Zero Sweep Filter and Subkeeper Saturator, two freeware effects for macOS and Windows.
I love the minimal design of these plugins. White on black looks clean, and I think it fits the general idea behind these plugins because they both address a specific production problem without adding a bunch of controls you won’t need.
Zero Sweep Filter handles the familiar transition effect of sweeping a high-pass or low-pass filter. Making the sweep is the easy part, but returning to a completely clean signal often means automating the bypass or adding a wet/dry move alongside the filter.
Stemwire designed Zero Sweep so that it leaves the signal untouched at rest. You can automate the filter with a single lane and return smoothly to the original sound without residual filtering, bypass clicks, or the phase issues that can come with a wet/dry crossfade.
It’s definitely handy for stuff like build-ups and breaks. You can leave it loaded on a channel, bus, or master, and use it for multiple transitions.
Subkeeper Saturator solves a different problem. Saturation can add body and character, but pushing it hard often makes the low end muddy.
Its Sub Protect control filters the signal entering the saturation stage. Frequencies below the selected point remain in the full-band signal, but they do not enter the nonlinearity and generate additional harmonics.
In other words, you can drive the mids and highs while keeping the lowest frequencies cleaner. Nice and simple.
There are four saturation characters. Gentle is the softest, Round applies more pressure, Bite sounds more cutting, and Crush delivers the strongest effect. The Sub Protect setting remains consistent when switching modes, and Stemwire has included 16x oversampling to reduce aliasing.
Zero Sweep Filter and Subkeeper Saturator are pay-what-you-want downloads with a free option. Neither requires an account or activation, and both work offline. The plugins are available in VST3 and AU formats for macOS, and VST3 for Windows.
Download: Stemwire Zero Sweep Filter / Stemwire Subkeeper Saturator (FREE / Pay what you want)
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Last Updated on August 19, 2026 by Tomislav Zlatic.
