NUSofting has released Filter4Tongue Free, a creative filter-based effect plugin available as a free download (with optional donations) for Windows.
The developer describes Filter4Tongue as a “Hyper Wah,” “Formant Maker,” and a “Drone Shaper.” It’s definitely aimed to be more of a sound design tool than a filter for basic mixing and tone shaping.
Sound design plugins are precisely my cup of tea, but unfortunately, I haven’t been able to test this one myself due to it being Windows-only. I’m currently traveling and only have access to a MacBook.
With that in mind, I can only write this article based on the screenshots and the official info available on the Filter4Tongue product page. And looking at the screenshot, it seems like one of those plugins that invites you to experiment instead of blindly following the manual (which is good, because there isn’t one).
The core of Filter4Tongue Free is a dual-band filter bank setup, or to be more precise, two serial pairs of band-pass filters routed in parallel.
This type of setup should allow for both symmetrical and divergent tuning, and let you emphasize specific formants or create modulated resonances, which are cool for building drones and textures.
And there’s a lot of modulation potential, at least on paper. The plugin includes an envelope follower with a loop mode and four assignable targets, so there’s plenty of room for rhythmic filtering or dynamic shaping.
A pink noise generator is also included and can be used as a modulation source (nice!) or layered into the signal path for extra texture.
There’s also a saturation feature that kicks in when pushed into overdrive territory, which might be handy if you want some analog-style warmth or chaos, depending on how far you push it.
While it’s hard to categorize Filter4Tongue neatly without testing it, it seems like a solid option for formant filtering, modulation, or even borderline FSU effects. The demos show it used on guitars, synths, and drums, and the results are anything but subtle.
It’s worth noting that this is just the free version. NUSofting is considering an expanded, paid version with features like precise musical tuning, host-synced step LFOs, stereo processing, oversampling, and more presets and tutorials.
But the development of that version depends on user interest and donations, so now’s a good time to show support if you find the plugin useful.
Filter4Tongue Free is available in VST2 and VST3 formats for 64-bit Windows 10/11 systems. There’s no registration required to download, but donations are encouraged if you’d like to support future development.
If you’re on Windows and give it a try, please drop your impressions in the comments. I’d love to hear what it can do in action.
Download: Filter4Tongue Free (Windows-only)
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Last Updated on September 15, 2025 by Tomislav Zlatic.

