Circuit-modeled filtering. Now in motion.
FILTRONIX PRO
Built from 3,000+ FILTRONIX Free downloads and real user feedback.
FILTRONIX is a circuit-modeled filter plug-in for shaping tone, adding drive and bringing analog character to your tracks. Pro adds three filter modes, rhythmic LFO movement and an envelope follower.
Analog character without losing control.
FILTRONIX combines circuit-inspired filtering with modern DSP techniques for smooth resonance, controllable drive, and practical mix-ready operation.
Circuit modeling
Model the behavior
Filter topology, feedback, saturation, and resonance interact as one system instead of a stack of unrelated effects.
ZDF / TPT
Keep resonance responsive
Zero-delay feedback topology supports smooth cutoff movement and stable behavior at high resonance.
Nonlinear drive
Add tone with clarity
ADAA saturation and 4x oversampling help control aliasing while the Drive stage adds weight and edge.
Visual feedback
See the filter move
The spectrum and response display make cutoff, resonance, and tonal changes easy to follow.
Go further with Pro.
Add new filter modes, motion and a dedicated preset workflow.
Three filter modes
Choose what comes through.
Low-pass, high-pass and band-pass across all four models, with 2-pole and 4-pole operation.
Tempo-synced LFO
Give the filter a pulse.
Six waveforms, tempo sync and independent cutoff and resonance depths for rhythmic sweeps and evolving textures.
Envelope follower
Let your playing lead.
Turn input dynamics into cutoff and resonance movement, shaped by sensitivity, attack and release.
Factory & user presets
Start inspired. Keep your favorites.
24 factory sounds plus Init, with an in-plugin USER library to save and manage your own presets.
Free or Pro?
| Feature | Free | Pro |
|---|---|---|
| Price | Free | $9 intro Regular $19 USD |
| Formats | Windows VST3 macOS AU & VST3 |
Windows VST3 macOS AU & VST3 |
| Filter models | M / S / P / W | M / S / P / W |
| Filter modes | Low-pass | Low-pass, high-pass, band-pass |
| Filter slope | 2-pole / 4-pole | 2-pole / 4-pole |
| Drive & Analog | Included | Included |
| 4x oversampling | Included | Included |
| Built-in LFO | Not included | 6 shapes, tempo sync, rate & phase |
| Envelope follower | Not included | Sensitivity, attack & release |
| Modulation targets | No built-in modulation | Cutoff & resonance, with signed depths |
| Factory sounds | Default setting | 24 presets + Init |
| In-plugin USER library | Not included | Save, load, rename & delete |
| Spectrum & response display | Included | Included |
Pro’s HP and BP modes extend the circuit-inspired models; they are not claims about modes on the original hardware. The envelope follower responds to the input signal, not an external sidechain.
Looking for the Free Edition? Learn more about FILTRONIX Free →
FAQ
What makes FILTRONIX different from a standard digital filter?
FILTRONIX models circuit-inspired feedback and nonlinear behavior, combining ZDF / TPT filtering, saturation and oversampling. The interaction between resonance, Drive and the selected model is part of its character, rather than just a change to the frequency curve.
Why use 4x oversampling?
Oversampling gives nonlinear processing more internal bandwidth and helps reduce unwanted aliasing when Drive and resonance are pushed. Both Free and Pro use 4x oversampling; it is part of the shared engine, not a Pro-only feature.
Is FILTRONIX still available for free?
Yes. FILTRONIX Free is available separately with the core low-pass filtering engine. See the Free Edition link below the comparison table.
What does Pro add to Free?
Pro adds high-pass and band-pass modes, a tempo-syncable LFO, an input envelope follower, 24 factory sounds plus Init, and an in-plugin USER preset library.
Can the LFO and envelope follower work together?
Yes. Each source has its own cutoff and resonance depths, so you can combine rhythmic modulation with a response to the incoming performance.
Which plug-in formats are available?
Both editions are available as VST3 for Windows and as AU and VST3 for macOS. Choose the format supported by your DAW.
How much is FILTRONIX Pro?
The introductory price is $19 USD. The regular price is $29 USD.
Give your filters motion.
Shape your sound with three filter modes, a tempo-synced LFO and an envelope follower.