Noise Engineering Roucha Legio

NoiseEngineering RouchaLegio

Boutique modular synthesizer company Noise Engineering announced Roucha Legio, a stereo resonant multimode filter with wavefolding, 1V/octave tracking, and gateable bypass, at Superbooth. The Eurorack module is available May 11. Roucha Legio is a 12dB/octave state-variable stereo multimode filter. It is the fourth module in the Legio series of many that the Noise Engineering team has said they are working on.

“We argued for so long about the core of this firmware. We started with something completely different but we just couldn’t quite agree on the finer points. So we took a step back and decided that we should probably work on a filter, since people have been asking for one for years,” said Kris Kaiser, Doer of Many Things at Noise Engineering. “The next firmware Stephen dropped for us to test was so much fun that our team Slack workspace went silent while we all started patching. We knew this was the one.”

Roucha Legio features lowpass, bandpass, and highpass filter settings. The filter frequency is adjustable via the dedicated encoder or the one-volt-per-octave CV input. Roucha Legio is designed not to self-oscillate without an input signal, but once a signal is added, the Resonance control can offer anything from clean to the squelch of an acid house bassline. Resonance is also CV-able, which means filter sweeps are easy to achieve.

Noise Engineering has a love for wavefolders, so of course there is a Fold knob, with a switch that configures the placement of fold in the signal chain before, after, or both before and after the filter. Roucha Legio also features a bypass control. Tap the encoder to bypass the DSP, and tap again to re-enable it. The dedicated Bypass gate input also works to bypass the filter while the input is high.

Roucha Legio is part of the Noise Engineering Legio DSP/oscillator platform. Users can change the firmware on any Legio module, completely free, to any other firmware in the Legio series via USB. Current offerings include the Virt Iter Legio oscillator (based on the same algorithms that Noise Engineering contributed to the Arturia MicroFreak and MiniFreak), Tymp Legio drum voice, and Librae Legio dynamics processor.

To help keep the panel controls straight with all the different firmwares available, Noise Engineering also offers laser-etched, impact-acrylic panel overlays that fit right over the existing panel. Overlays are available in silver with black text or black with white text, and as individual panels or in discounted multipacks.

Roucha Legio ($310 USD) and Legio panel overlays ($16 each or $48 for the 4-panel multipack) are available now at and at retailers globally. Current Legio owners can try Roucha for free by heading to the Noise Engineering Customer Portal ( to swap the firmware.

Notable features

  • 6 HP
  • CV-able inputs
  • Bypassable filter
  • 1v/8va tracking
  • Self-calibrating frequency CV
  • Part of Legio ecosystem: buy one module, get them all
  • Hotswappable panel overlays sold separately

Availability and pricing

  • Roucha Legio: In stock in black and silver. Shipping from Noise Engineering and retailers starting May 11, 2023; US$310
  • Overlays: In stock in in silver with black text or black with white text, and as individual panels or in discounted multipacks
  • Legio single panel: $16
  • Legio multipack (4 panels): $48