FabFilter Simplon: A Beginner’s Guide to the Classic Filter PluginFabFilter Simplon is a compact, musical filter plugin designed for shaping tone, adding movement, and creating creative effects. It’s praised for its clean sound, flexible routing, and simple but deep modulation options. This guide walks you through what Simplon does, how its controls affect sound, practical uses, step‑by‑step setup examples, and tips for getting musical results quickly.
What Simplon is and when to use it
FabFilter Simplon is a stereo multimode filter with two independent filter stages, a flexible saturation option, and easy-to-use modulation. Use it when you need to:
- Tame or emphasize frequency bands with transparent filtering.
- Create rhythmic or evolving motion by modulating cutoff, resonance, or routing.
- Add analog‑style color with tasteful saturation.
- Produce sweeps, build tension, or carve space in a mix without complex setup.
Key takeaway: Simplon is both a corrective and creative tool—transparent for surgical filtering and musical for sound design.
Main interface and controls (what they do)
- Cutoff — sets the filter’s corner frequency. Moving it left removes highs (for low‑pass) or boosts/removes lows (for high‑pass).
- Resonance — emphasizes frequencies around the cutoff. At moderate settings it adds character; high settings create whistling or self‑oscillation.
- Filter Type — choose from common modes (low‑pass, high‑pass, band‑pass, notch, etc.). Each changes which part of the spectrum is passed or removed.
- Slope — determines how steeply frequencies are attenuated (e.g., 6/12/24 dB/oct). Steeper slopes create more isolation between passed/removed bands.
- Mode Linking & Stages — Simplon has two filter stages that can be used in series or parallel; you can route them to create complex responses (e.g., band‑pass from series HP + LP, or wider notch in parallel).
- Drive / Saturation — mild harmonic distortion used to warm the signal and add presence. Useful for making filtered parts sound fuller.
- Stereo controls — mid/side or left/right processing options let you target spatial elements (e.g., high‑pass the sides, low‑pass the center).
- Envelope follower & LFO — built‑in modulation sources to animate cutoff, resonance, or other parameters without an external host.
- Presets — good starting points for common tasks like sub cleaning, hi‑cut for mastering, vocal tone shaping, rhythmic gating, and more.
How to set up Simplon in your DAW
- Insert Simplon on the track you want to process (instrument, vocal, bus, or master).
- Choose a filter type and set cutoff roughly where you want the tonal change.
- Adjust resonance to taste. Keep it low for subtle shaping, higher for character and movement.
- Set slope according to transparency needs: gentle slopes for natural roll‑off, steep for clear separation.
- Add Drive if the filtered sound sounds thin—use sparingly on mixes.
- Use the stereo controls if you want to affect center or sides differently.
- Add an LFO or envelope follower if you want motion tied to tempo or dynamics.
- Automate cutoff or LFO rate for transitions (builds, drops, risers).
Practical examples and workflows
- Sub cleaning on bass: place a high‑pass with a gentle slope on the bass bus (around 20–40 Hz) to remove inaudible rumble; use low‑pass on synths to give the bass space.
- Vocal de‑essing alternative: use a narrow band‑pass or notch to reduce sibilance frequencies and subtly automate cutoff with an envelope follower.
- Rhythmic filter on pads: set a low‑pass, moderate resonance, and sync the LFO to project tempo (try square or stepped shapes for chopping).
- Drum bus movement: place Simplon on the drum bus, set a band‑pass or high‑shelf movement via LFO to create groove‑coherent movement.
- Creating risers and transitions: automate cutoff from low to high with rising resonance and increased drive for dramatic build-ups.
Tips for musical results
- Use subtle resonance when mixing — extreme resonance can mask other elements or sound harsh.
- Automate parameters rather than extreme static settings to keep parts dynamic and evolving.
- When using two stages, experiment with series vs. parallel routing — series tightens the response, parallel keeps the sound fuller.
- Use mid/side processing to avoid collapsing the stereo image when filtering the same content on left and right channels.
- If you hear pumping or unwanted artifacts when using envelope follower or extreme modulation, reduce modulation depth or use smoother LFO shapes.
Common mistakes and how to avoid them
- Over‑resonating: makes mixes thin or shrill — dial back resonance or automate it only during effects.
- Too steep slopes on musical parts: can make things sound unnatural; prefer gentler slopes for pads and vocals.
- Overusing drive: can add unwanted distortion on masters; use on individual tracks instead.
- Neglecting phase: steep filters can introduce phase shift — listen in context, and prefer gentler settings on material sensitive to phase (e.g., bass).
Quick presets to try (starting points)
- Sub clean: HP 30 Hz, slope 12 dB/oct, resonance 0–10%, stereo width unchanged.
- Vocal presence: BP centered ~3–6 kHz, Q moderate, small drive.
- Smooth pad: LP 6–10 kHz, slope 12 dB/oct, slow LFO to cutoff, gentle resonance.
- Punchy drums: BP around 100 Hz for body + HP to remove sub rumble; mix parallel for clarity.
- Sweeping riser: LP start ~200 Hz → automate to 20 kHz over 8 bars, resonance up, drive slight.
Final notes
FabFilter Simplon is deceptively simple: its interface is approachable, but the dual‑stage routing, modulation, and saturation let you move from surgical mixing tasks to expressive sound design quickly. Start with conservative settings, listen in context, and use automation and modulation to bring life to static tones.
Bottom line: Simplon is a versatile, musical filter—great for both corrective EQ tasks and creative modulation-based effects.