AOFN Audio has released Grizzly, a free stereo modulation plugin for macOS and Windows.
Grizzly is modeled on the 1979 Gristleizer circuit, the strange little LFO-driven pedal that Chris Carter of Throbbing Gristle famously used on drum machines, tapes, synths, and plenty of other sources. Developer Marcel describes Grizzly as his software interpretation of that pedal, taken from the modulation section of an upcoming reverb plugin.
Before getting to the sound, I have to say that I love the interface. The black-and-white color scheme is always nice to see, probably because I’m a Partizan Belgrade fan, so those colors are ingrained somewhere deep inside.
The website looks nice, too, and nowadays anything with some originality and character gets bonus points from me because we are surrounded by an ever-growing pile of copy/paste generic AI-generated stuff.
The basic idea with this one is simple, but the sound can get pretty wild. An internal LFO drives a modeled JFET stage, which can either duck the amplitude of the incoming signal or sweep a lowpass filter across it.
In VCA mode, Grizzly works as a tremolo, rhythmic gate, choppy pumping effect, or slow pulsing modulator. But if you push the speed beyond 20 Hz, it moves into ringmod-adjacent territory, where the modulation starts interacting with the pitch of the source.
In VCF mode, the same LFO opens and closes a lowpass filter. That can give you autowah-style movement, slow sweeps, or other interesting types of modulation that I especially enjoyed on heavy synth bass during the test.
The LFO offers triangle, square, saw up, and saw down shapes. Speed runs from 0.01 Hz to 30 Hz, or it can sync to the host tempo with note divisions from 1/1 down to 1/32.
There are no presets and no menus. Grizzly gives you ten knobs and a bypass switch, which feels right for this kind of effect. The controls include Drive, Speed, Depth, Shape, Offset, Bias, Wave, Mode, Spread, and Level.
Drive sits before the modulator and models the original circuit’s op-amp amplifier stage. It can act as a pad at lower values or add warmth and harmonic texture when pushed harder.
Offset and Bias are important for shaping how much of each LFO cycle actually fires the effect and where the modulation rests between pulses. Pulling Offset back with a slower speed is the quickest route to the characteristic Gristleizer-style rhythmic stutter.
Spread offsets the LFO phase between the left and right channels, widening the stereo movement. I love how it can create a ping-pong-style gate at higher settings, especially with a fast square wave.
Grizzly is free, but you need to enter an email address to receive the installer and read-me. It is available in AU and VST3 formats for macOS 12 or later (Apple Silicon and Intel) and VST3 format for Windows 10/11 x64.
Download: AOFN Audio Grizzly (FREE)
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Last Updated on July 21, 2026 by Tomislav Zlatic.
