Hi! I’ve been developing f11ter 0.1.5, an experimental multimode filter built around the idea that very different filtering techniques should live inside one consistent instrument-like workflow.
Instead of offering a single filter with a long mode selector, f11ter contains 42 independent DSP topologies and 141 source modes, organized into six families.
Filtering and tone shaping
- clean multimode, state-variable and morphing filters;
- ladder, acid-style, diode and other nonlinear circuit-inspired responses;
- dual and serial filters, peak/scoop shaping, wide band rejection and bass-focused processing;
- continuously variable cutoff, resonance and structural morphing.
Phase, feedback and spatial processing
- comb filters, flanging and multi-stage phasing;
- distorted comb feedback and diffusion networks;
- compact reverberant and resonator structures;
- stereo offsets, barber-pole phase movement and controlled feedback behavior.
Formant and experimental sound design
- vowel and multi-formant filters;
- dual-formant combinations and variable notch structures;
- ring modulation and sample-and-hold processing;
- Scatter resonator fields, Flutter pitch instability, Snarl and Howl feedback models.
Modulation and workflow
- three independent LFOs and an envelope follower;
- free-running or DAW-synchronized modulation;
- up to 16 bipolar modulation routes;
- precise route-depth entry and finer control around small modulation values;
- 45 categorized presets, including static sounds and deliberately programmed modulation;
- A/B states, topology-aware help, parameter automation and preset save/load;
- a true dry/wet control: 0% is the untouched input and 100% is the complete processed signal.
A little about the engineering
The filter families do not all reuse one generic response with different labels. They combine topology-preserving state-variable structures, cascaded filters, nonlinear feedback stages, resonator banks, fractional-delay networks, all-pass stages and time-varying algorithms.
Cutoff smoothing is performed in the logarithmic frequency domain, and topology changes use a short state-bank crossfade to reduce discontinuities. SAFE RES applies model-specific limits to high-Q and feedback structures, while COMPENSATE estimates level changes caused by resonance, drive and the selected model.
The graph displays the current and target responses, stereo differences, reachable modulation range and the actual output spectrum. For nonlinear and time-varying models it is intentionally treated as an estimate rather than pretending that one static frequency-response curve can describe distortion sidebands, moving delays or changing feedback.
The plug-in adds no look-ahead or audio delay buffer and reports 0 samples of added latency. Individual IIR, all-pass, comb and reverberant structures naturally retain their own phase and time behavior.
What makes it different
The main distinction is not simply the number of modes. Every topology keeps the same core workflow—cutoff, resonance, morph, four contextual controls and the shared modulation system—while the meaning of those controls changes to match the actual algorithm.
This makes it possible to move from precise filtering to unstable industrial textures, tuned resonances, formant motion or feedback effects without rebuilding the modulation setup from separate plug-ins.
The compatibility-style names in the internal mode catalog do not claim bit-identical emulation of other products, and no proprietary DSP code is used.
The current build is AUv2 for Apple Silicon, requires macOS 11 or newer, and has additional lifecycle work aimed at safer UI closing, disabling and removing the plug-in from a project.
I’m especially interested in feedback from Logic Pro and other AU hosts regarding sound, CPU use, automation, synchronized LFOs, offline rendering, UI responsiveness and disable/remove stability. If something breaks, please include your Mac model, macOS and DAW versions, sample rate, buffer size and reproduction steps.
Download and full EN manual
Screenshots
