Developer Tone2 has updated its Windows-only plugin BiFilter to version 2.5, making it now freeware.
BPB covered BiFilter way back in 2012, when Computer Music Magazine featured it as a giveaway for readers.
Back then, if you didn’t pick up BiFilter through the giveaway, it would cost you around $39.99.
Now, in version 2.5, BiFilter makes the welcome move to freeware, and it comes with some notable improvements and fixes.
The move to freeware comes as Tone2 decided that BiFilter was no longer a viable commercial product, but didn’t want to ditch almost 20 years of history without one last hurrah.
Version 2.5 is the final update, a thank you to our loyal customers, and an opportunity for new customers to experience an old favourite for free.
BiFilter is a stereo multi-mode filter with 47 unique filter types, eight types of distortion, and 100 factory presets.
The filters come from the developer’s flagship Gladiator synthesiser.
Filter types include LP/HP with varied slopes, notch, shelving, band-pass, phaser, comb, vocal format filters, and more.
You can see a complete list of filter types on the BiFilter product page.
The eight distortion types include Volume, Tube Amp, Transistor, Presence, Hard Clip, Bitcrush, Waveshape, and Pow2 (adds harmonics similar to exciters).
Tone2 created BiFilter to be a versatile filter with an intuitive, easy-to-use interface and low CPU usage, and it lived up to that reputation for almost two decades.
BiFilter is available in 64-bit VST format for Windows (7 – 11).
Tone2 explained that it’s not possible to port the plugin to Mac or VST3 within the realm of reasonable effort.
If you’re on the lookout for a Mac-friendly, cross-platform filter plugin, try the free FILT-R by Tilr.
Tilr has been one of the busiest developers of 2025, so far, and if you haven’t checked them out yet, I highly recommend doing so.
Recent Tilr freebies include TIME-12 (time modulation), GATE-12 (volume modulation), and REEV-R, an excellent convolution reverb plugin.
All Tilr plugins are compatible with macOS, Windows, and Linux operating systems.
Lastly, don’t forget you can grab AIR Music Tech’s Channel Strip for free throughout July 2025 (it’s available as a standalone plugin for the first time ever).
Download: BiFilter 2.5 (Freeware)
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Last Updated on July 3, 2025 by Tomislav Zlatic.

