Bastl Instruments Ikarie
Dual-core stereo filter with formant soul and cosmic range
8 HP Eurorack module
Ikarie is a flexible stereo or dual-peak filter module featuring two parallel 12dB/oct state variable filter cores that can continuously sweep between lowpass and highpass with a single knob. It includes a built-in envelope follower, voltage-controlled resonance, input overdrive, stereo VCA, and a unique Beyond output that delivers the spectral difference between the two filters. The module excels at vocal formant tones, twin-peak filtering, self-oscillation, percussive pinging, and experimental stereo sound design.
Features
- Two parallel 12dB/oct state variable filter cores (left and right)
- Continuous lowpass to highpass sweep via single CUTOFF knob
- Unique VCA-based LP/HP switching topology
- Stereo or dual-peak mono operation
- BEYOND output for spectral difference (twin-peak filter)
- Envelope follower with three decay/speed settings (Slow, Mid, Fast)
- Envelope follower normalized to MOD input for auto-filter/auto-wah
- Input gain from unity to 5x overdrive
- Voltage-controlled resonance with fader as attenuator when CV connected
- MOD input with attenuverter for bipolar CV modulation of cutoff
- V/OCT input for pitch-tracking with front-panel accessible scaling trimmer
- STEREO section with SPREAD (cutoff detuning) and PAN (level panning) modes
Controls & Jacks (26)
- Input — Controls input level from silent to 5x gain. Affects filter character and sensitivity; mid-way provides clean balanced resonances, extreme s
- Mod — Attenuverter for MOD input controlling CUTOFF of both filters. Center position blocks modulation; CW opens positive modulation, CCW inverts
- Stereo — Controls stereo spread/pan effects. In SPREAD mode: detuning between left and right cutoff frequencies. In PAN mode: panning or crossfading
- Cutoff — Continuously transitions between lowpass (CCW) and highpass (CW) filtering. Center position is open filter. Voltage controlled via CV MOD, V
- Follow — Envelope follower output tracking loudness of left input signal. Selectable responsivity (Slow/Mid/Fast). Normalized to MOD input for auto-f
- L In — Left channel audio input; normalizes to R In
- R Out — Right filter output; can receive L Out for serial 24dB filtering
- Mod — CV input modulating CUTOFF of both filters in tandem. FOLLOW output is normalized here unless overridden by patch cable.
- V/Oct — Volt-per-octave pitch control for both filters
- Stereo — CV input for stereo modulation. Modulates SPREAD or PAN mode depending on switch setting. Knob becomes attenuator when cable connected.
- L Out — Left filter output; use alone for mono or with R Out for stereo
- VCA CV — Output level control via internal VCA (0-5V)
- R In — Right channel audio input; normalized from L In
- Beyond — Spectral difference output between two filters. Creates twin peak/bandpass behavior or ring modulation effects when combined with PAN mode.
- Follow Speed — Selects envelope follower responsivity: Slow (natural pumping), Mid (tight, mid-range), or Fast (hard edge, full-wave rectifier).
- Stereo Mode — Selects between SPREAD (detuning filter frequencies) and PAN (level panning/crossfading) modes for stereo control.
- RESONANCE — Fader emphasizing CUTOFF frequency with partial or full self-oscillation. Acts as main control when no CV is patched; becomes attenuator for
- RESONANCE CV — input jack
- STEREO — Selects between SPREAD (detuning filter frequencies) and PAN (level panning/crossfading) modes for stereo control.
- FOLLOW — Selects envelope follower responsivity: Slow (natural pumping), Mid (tight, mid-range), or Fast (hard edge, full-wave rectifier).
- V/OCT trimmer — Rear-panel flathead screw trimmer to calibrate V/OCT tracking scaling
- Mod CV — Modulation input for CUTOFF; FOLLOW normalized here
- MOD input — Modulation input for CUTOFF; FOLLOW normalized here
- STEREO CV — Modulation for SPREAD or PAN stereo effects
- FOLLOW output — Envelope follower output tracking left input loudness
- BEYOND output — Twin peak filter / spectral difference output
How-To Guides
- Vocal Formant Filtering
- Quad Acid Sweep
- Beyond Stereo Imaging
- Percussive Pinging
- Self-Oscillating Sine Generator
- Auto-Filter / Auto-Wah
- Post-Filter Ring Modulator
- Aggressive 24dB Series Filter
- Waveform Crossfading
- Sidechain Auto-Filter
Explore the interactive Ikarie panel on BleepDex — tap any control to learn what it does.
