rossum-electro-music-linnaeus

Rossum Electro-Music Linnaeus

Stereo thru-zero state variable filter with Ping Mode

16 HP Eurorack module

Linnaeus is a stereo thru-zero state variable filter from Dave Rossum that can linearly modulate its resonant frequency through zero into negative frequency while remaining stable — opening timbral territory unattainable with exponential modulation. Cutoff is exponentially VC from sub-audio to ultrasonic; resonance (Q) is VC from 0dB to over 60dB. Each of the two channels has a continuously variable response (LP/BP/HP/Notch/Shelf) that can be set and modulated independently, while sharing cutoff and Q. An integrated morphing mod oscillator and external linear FM input drive the thru-zero modulation, and an alternate Ping Mode turns Linnaeus into a self-contained stereo oscillator and FM percussion voice.

Features

  • Stereo state-variable filter with shared cutoff/Q but independent per-channel response
  • Thru-zero linear frequency modulation into negative frequency, while staying stable
  • Continuously variable response: LP (12/6dB), Bandpass, HP (12/6dB), Notch, Low/High Shelving
  • Resonance (Q) exponentially voltage-controllable from 0dB to over 60dB (never self-oscillates)
  • Integrated mod oscillator with continuously morphing wave (Off→Sine→Tri→Saw→Square)
  • Mod oscillator can track the filter frequency (Track button)
  • Linear Mod Index VCA, voltage-controllable from 0 to 8x
  • Per-channel Response CV enable with selectable polarity (green +, red -)
  • Q Compensation to tame or dial in high-Q overdrive distortion
  • Ping Mode: self-contained stereo oscillator / FM percussion voice
  • DC-coupled stereo inputs/outputs (process audio or CV), 20V p/p, left normalled to right
  • Field-updatable firmware via WAV playback into Ext Lin CV

Controls & Jacks (32)

  • Response CV
  • Response/Q Comp
  • Wave
  • Filter Freq
  • Filter Q
  • Mod Index
  • Osc Freq
  • Freq CV Attenuverter
  • Q CV Attenuverter
  • Index CV Attenuverter
  • Osc Freq CV Attenuverter
  • Response CV Enable L
  • Response CV Enable R
  • Response Enable L
  • Response Enable R
  • Track/Ping
  • Response CV Enable L LED
  • Response CV Enable R LED
  • Response Enable L LED
  • Response Enable R LED
  • Track LED
  • Freq CV In
  • Q CV In
  • Index CV In
  • Osc Freq CV In
  • 1V/OCT
  • 6dB/V
  • Ext Lin CV
  • Input L
  • Input R
  • Output L
  • Output R

How-To Guides

  • Stereo Response Morph
  • Thru-Zero Linear FM Bells
  • Taming High-Q Distortion
  • Dynamic Index Modulation
  • Ping Mode FM Percussion

Explore the interactive Linnaeus panel on BleepDex — tap any control to learn what it does.

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