Roucha Legio#

Stereo resonant multimode filter with wavefolding, 1v/8va tracking, and gateable Bypass

Overview
Etymology
Color code
Power
Input & output voltages
Calibration
Interface
Patch tutorial
Firmware swapping
Design notes
Warranty
Special thanks

Overview#

Roucha Legio is a 12dB/octave state-variable stereo multimode filter with settings for lowpass, bandpass, or highpass operation. Its filter frequency can be adjusted manually or, thanks to its proudly digital design, with an extremely accurate 1v/8va-tracking CV input. Its CV-controllable Resonance parameter goes from clean to squelchy, perfect for acid basslines and in-your-face filter sweeps.

If that’s not enough for your patch, the Fold knob adds wavefolding to the signal chain, either before, after, or both before and after the filter.

Last of all, if you like dramatic buildups and DJ-style filter cuts, all processing can be bypassed by tapping the frequency encoder or by sending a gate signal to the module.

Type: Stereo filter and wavefolder
Size: 6HP
Depth: 1.5 Inches
Power: 2x5 Eurorack
+12 V: 140 mA
-12 V: 22 mA

Etymology#

Roucha -- from Latin: "pants"

Legio -- from Latin: "legion"

"Lots of laundry"

Color code#

On boot, the Legios's LEDs will shine with this color pattern to indicate that it is running the current Roucha Legio firmware:

A illustration of two lights. From left to right, the lights are colored blue and green.

Power#

Power connector

To power your Noise Engineering module, turn off your case. Plug one end of your ribbon cable into your power board so that the red stripe on the ribbon cable is aligned to the side that says -12 V and each pin on the power header is plugged into the connector on the ribbon. Make sure no pins are overhanging the connector! If they are, unplug it and realign.

Line up the red stripe on the ribbon cable so that it matches the white stripe and/or -12 V indication on the board and plug in the connector.

Screw your module into your case before powering on the module. You risk bumping the module's PCB against something metallic and damaging it if it's not properly secured when powered on.

You should be good to go if you followed these instructions. Now go make some noise!

A final note. Some modules have other headers -- they may have a different number of pins or may say "not power". In general, unless a manual tells you otherwise, do not connect those to power.

Input & output voltages#

Roucha Legio’s CV-modulation inputs expect signals from 0 V to +5 V, except the Freq input, which has a range of -2 V to +5 V. The Bypass input responds to a rising edge around +1.6 V.

The the audio inputs are AC coupled and respond to any Eurorack audio signals. When used for pinged filter patches, a very short trigger will work best.

The audio output can reach up to 16 V peak-to-peak.

Calibration#

Roucha Legio features an autocalibration system. The modules are autocalibrated and tested at the factory, but should you feel you need to recalibrate, just power the unit on with nothing patched to the Freq CV input. The module will calibrate itself during startup.

Interface#

An illustration of Roucha Legio's interface

Frequency: Turning the encoder adjusts the frequency of the filter. The encoder features acceleration: the faster the encoder is turned, the greater the change in frequency.; Tapping the encoder will bypass all processing until the encoder is tapped again.
Resonance: Emphasizes sound around the cutoff frequency. Roucha won’t self-oscillate until it is excited by external input.
Fold: A wavefolder that can be placed at different points in the signal chain with the left switch.
All/Post/Pre: Changes the position of the wavefolder in the signal chain.

All: The wavefolder is both before and after the filter
Post: The wavefolder is after the filter
Pre: The wavefolder is before the filter

HP/BP/LP: Set the filter frequency with the encoder and use this switch to change the filter type.

HP: Sound above the cutoff frequency is let through; sound below the cutoff is suppressed
BP: A narrow band of frequencies around the cutoff frequency are allowed through; sound above and below the band are suppressed
LP: Sound below the cutoff frequency is let through; sound above the cutoff frequency is suppressed

Bypass (gate input): When a high gate is sent to this input, all processing is bypassed and the dry signal is passed through. When a low gate is present at the input, the filter functions as usual.
In L/In R: Audio inputs. If R is unpatched, L will normal to R.
Out L/Out R: Audio outputs.

Patch tutorial#

Getting started: Patch a sound source like an oscillator, a sample, or a mix of elements to the L In jack (and the R In jack if the sound is stereo). Patch Out L (and Out R for stereo operation) to your mixer.; Set Fold and Resonance fully counterclockwise to start. Adjust the frequency of the filter with the encoder and try out the different filter modes (LP, BP, and HP).; Turn up Resonance to make the filter more characterful, and turn up Fold to add some distortion to your signal.; Try modulating the filter frequency with an envelope, LFO, or step sequencer.; Try bypassing the filter by tapping the encoder, or send a gate sequence to the Bypass jack to create glitchy filter cuts.; The module can also be used as a simple voice: patch a trigger sequence to L In and turn the Resonance up to change how long the voice rings out when it’s triggered. A pitch CV sequence can be patched to the Freq input to play melodies, and the switches and Fold parameter will change the timbre of the voice.

For the following patches, set the filter frequency to taste. We generally began patching with the filter between 500hz-1khz."

Rhythmic Filter: Patch a rhythmic sound source (like a sequenced drum loop) to In L (and In R if sound is stereo). Patch Out L and Out R to your mixer. Set knobs as shown, and flip the switches to All and LP. Patch gate sequence to the Bypass input to add filtered layers to your drum pattern.