O2

O2 — Stereo 3-Band Saturation & Width Processor

Five families of analog character. Four variants each. Three independent bands. Twenty distinct textures before you've even touched Feedback or Drift.

O2 splits your signal into Low, Mid, and High bands through phase-perfect first-order crossovers — dial saturation to zero and the bands sum back to bit-transparent, no coloration, no filter smear. Then it gives each band its own choice of saturation character, drawn from five hardware-inspired families (Diode, Op-Amp, Transformer, Tape, Tube), each with four named variants tuned for a specific job. Add per-band feedback, drift, noise, and M/S width, a global Tilt EQ, and a ducked Dry/Wet blend, and you have a processor that goes from "make this feel more analog" to full multiband harmonic sculpting without ever leaving one plugin.

Core Signal Path

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• Phase-Perfect 3-Band Split — first-order TPT crossovers reconstruct perfectly at zero drive; every bit of harmonic content you hear comes from the saturation stages themselves, not the filters.
  • 5 Saturation Families × 4 Variants, Per Band — Diode (asymmetric, aggressive, edge), Op-Amp (symmetric, clean odd-harmonic density), Transformer (frequency-dependent low-end bloom), Tape (hysteresis + HF rolloff), and Tube (even-harmonic warmth, from glowing preamp to tube-rectifier sag) — each band chooses independently.
  • Per-Band Character Controls — Feedback (resonant self-injection up to near-instability), Hiss (a gently drive-scaled analog noise floor), and Drift (slow, truly random modulation of Feedback and Drive for organic movement).
  • M/S Width + WIDEN — real mid/side width per band, plus a WIDEN toggle that synthesizes a mono-compatible side signal so even mono sources can open up.
    
  • Global Tilt EQ — a ±6 dB spectral seesaw around 800 Hz, post-sum, for warming or opening the whole processed signal in one move.

  Twenty Named Characters

  Every variant is a specific, evocative target rather than a generic "type 3" — Germanium Sunshine and Fuzz Therapy on the aggressive end of Diode, Double Espresso for transparent console-style density, Yorkshire Wool for Neve-style low-end bloom, Fahrenheit 456 for iconic tape crunch, Triode Sunrise for classic 12AX7 glow, Rectifier Dreams for tube-rectifier sag that breathes with transients. Pick the name that matches the record you're chasing, then dial Drive to taste.

  Highlights

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  • Ducked, equal-power Dry/Wet — the processed signal displaces the dry rather than stacking on it, so blending in harmonic density never gets muddy.
  • Per-band Bypass, Mute, Phase Flip, and gated Feedback (auto-mutes feedback under a sustained silence threshold, so resonant settings don't sustain noise).
  • 4× oversampling for alias-free high-drive processing, especially with Diode and Tube types.
    
  • MONO check toggle for verifying width decisions don't collapse in mono.

  What It's For

  Multiband analog-style saturation and harmonic enhancement, mix-bus glue and warmth, per-band width and mono-compatible widening, vintage tape/tube/transformer emulation on individual sources or full mixes, and surgical tonal sculpting where different frequency regions need genuinely different character rather than one blanket saturation curve.

  O2 is donation-ware — free to use, no strings attached. If it earns a place in your workflow, a tip is always appreciated: buymeacoffee.com/brittnell

  Format: VST3 (Windows & macOS) | Current version: 1.0.0.