Smurfilter - Random Step Filter VST3 (Free)
Random Step Filter Plugin · Free
Hold a chord and the filter starts talking. Every step it jumps to a new frequency and holds it there. Four knobs, a level, two switches, no menus.
$0+ Free · pay what you want
VST3 · Standalone · Windows 10/11 64-bit · v1.0.2
Sample and hold, in a stompbox
Nothing sweeps. Nothing repeats.
A wah follows your foot. An auto-wah follows your picking. This one follows nobody. On every step it picks a new frequency at random, jumps there, and holds it until the next step. Bubbling, chattering, vocal movement — locked to your DAW's beat if you want it, wandering on its own if you don't.
It is the sound of a lot of late-nineties and early-2000s funk-rock guitar: hold one chord and let the filter do the talking.
Smurfilter features
- Random step filter: a new frequency every step, held, never a sweep
- Three filter modes: low-pass, band-pass, high-pass
- FREE mode on its own SPEED, or SYNC to your DAW's tempo
- Sync from whole notes down to 1/32, with dotted and triplet values
- Stays on the grid when a loop jumps back
- Q from soft and wide to a narrow, ringing peak
- MIX from a hint of movement to filter only
- LEVEL, -12 to +12 dB, so it sits level with your bypass
- STEP lamp blinks on every jump
- Presets: save, recall, delete
- Sound quality 1x to 16x, window 50 to 150 %
- VST3 and Standalone, one download
Speed
How often it jumps, from a lazy drift to a fast stutter. With SYNC on it picks a note value instead and follows the tempo.
Freq
The centre the steps wander around, 180 Hz to 4.1 kHz. The jumps land about an octave above and below it.
Q
Soft and wide at the bottom, narrow and ringing at the top. Turn it up for the classic talking-filter sound.
The interface
One panel. Four knobs across the top, MODE and FREE/SYNC under them, the footswitch at the bottom with two lamps: ON is the bypass lamp and nothing else, STEP blinks on every jump so you can see the rate while you play.
The bar along the top holds your presets and the window size. Your DAW's bypass button and the footswitch are the same switch, so they never disagree.
Hear it in action
Why Smurfilter?
Steps that move
Plain random lands on two near-identical values in a row and sounds stuck. A step that lands too close to the last one is drawn again.
Jumps without clicks
A few milliseconds of glide between steps, short enough to stay a jump and long enough that a high Q does not pop.
Put it after the dirt
The filter has more to grab when there are harmonics in front of it. Run a fuzz or FC-2 Turbo (also free) first, Q high, MIX up.
Specifications
- Format: VST3 + Standalone
- Platform: Windows 10 / 11, 64-bit
- macOS: not supported in this version
- Channels: stereo in, stereo out
- Parameters: Speed, Freq, Q, Mix, Level, Mode, Free/Sync, Bypass
- Presets: save, recall, delete
- Sound quality: 1x, 2x, 4x, 8x, 16x
- Window: 50 / 75 / 100 / 125 / 150 %
- Every control automatable, footswitch included
- Version: 1.0.2
Windows
- Windows 10 or 11, 64-bit
- A VST3 host, or run the Standalone
- VST3 folder: C:\Program Files\Common Files\VST3\
macOS
- Not supported in this version
- Download only if you are on Windows
In the box
- Smurfilter.vst3
- Smurfilter.exe (Standalone)
- README.txt
Read this before you download
- Voiced by ear. There was no hardware unit on the bench and nothing was measured against one. The ranges come from documentation; the rest — the spread of the steps, the glide, the level — was chosen by ear.
- Not a sweep filter. There is no envelope and no LFO here. If you want a wah that follows your picking, this is not that.
- Windows only. No macOS build, no AU, no VST2.
Free, or pay what you want
Free. Same file at every amount.
No nag screen, no trial timer, and updates land in your library. If it earns a place on a session, put in an amount — it keeps the next pedal being built.
Leave it blank and Gumroad asks for a price at the next step. Zero is fine.
Changelog
- LEVEL control, -12 to +12 dB, bottom right of the panel
- Fixed the volume drop in band-pass at high Q
- First release
Thank God it's Filterday
A random step filter that is free and stays free. Windows VST3 and Standalone.