Format: Eurorack
Width: 20HP
Depth: 30mm
Current: 138mA@+12V(145mA with expander), 50mA@-12V
Frequency of each band: 29Hz / 61Hz / 115Hz / 218Hz / 411Hz / 777Hz / 1.5kHz / 2.8kHz / 5.2kHz / 11kHz (+-10%)
The Graphic Resonant Filterbank (FB) is a digitally controlled analog filterbank with 10 bands, each with its own boost or cut control. Each band can be individually controlled by CV or manually, and the complex settings allow the filterbank to be used as a non-traditional multimode filter, or even as an independent instrument with its own resonance settings.Expander Moduleallows you to directly adjust the boost and cut of all bands.presetis determined by the clock and CV.sequenceOrMorphingIs also possible
Feature:
The main menu allows you to access the main functions. The eight illuminated buttons below the OLED screen allow you toYou can access each function. For example, to activate the Filter Bank mode, press the top left button. You can select from the following menus:
Each mode and menu is explained below.
This is the most basic mode of the module, it sends the audio signal to the analog resonant filter bank and allows you to adjust the cut or boost of each bandpass filter. You can adjust one or several filters at the same time. Press the CH1 to CH1 buttons to select a filter (selected buttons will light up). To adjust the band level, rotate the DATA encoder. For finer adjustments, hold SHIFT and turn the DATA encoder. All selected bands are adjusted simultaneously. If you are using an expander, you can adjust each band directly without selecting them. Try changing the RESONANCE setting and hear how it changes the sound. At the 10 o'clock position you have no resonance, from there turning the knob counterclockwise gives you an inverted damping effect of the resonance. By holding SHIFT you can access secondary functions like resetting all bands to the center position, randomizing all, or randomizing only the selected bands. Randomization is an easy way to find cool and unique presets.
Saving presets
You can save your settings as a preset. To save, press and hold the DATA encoder for 3 seconds and the SAVE menu will appear. The three bottom row buttons will light up and show the functions DISCARD, RANDOM and SAVE. To name your preset, turn the DATA encoder to choose a symbol and press it to confirm your selection. Once you have decided on the name, press the rightmost SAVE button. You can DISCARD the save by pressing the leftmost button. Press the center button to generate a random name for your preset. Up to 3 presets can be saved. To exit the Filter Bank menu, press the BACK button.
The Multimode filter mode is a unique way of using the filter bank to sequentially vary the boost and/or cut of bandpass filters to emulate the behavior of a resonant lowpass, highpass, bandpass or notch (band reject) filter. Note that unlike a typical multimode filter, the filter response is composed of a series of bandpass filters and therefore will behave differently.
Once in Multi-mode Filter mode, hold SHIFT and press BAND4, BAND6, BAND8, or BAND10 to select Lowpass, Highpass, Bandpass, or Notch filter types. The filter mode is indicated visually and in the top right corner of the display. Each mode has slightly different settings, which are also indicated in the top right corner.
In Low Pass Filter mode you can adjust the Cutoff Frequency (F), Slope (S) and Resonance. To adjust the filter cutoff frequency, press and hold the SHIFT button while pressing the CH1 button (it will light up) and turn the DATA encoder to change the cutoff frequency. The control assigned to the encoder is shown in a circle around the relevant letter in the top right of the display. The cutoff frequency can also be CV controlled by applying a signal to the CV1 input. To adjust the filter slope, press and hold the SHIFT button while pressing the CH3 button (it will light up) and turn the DATA encoder to change the slope. The slope can also be controlled by a CV applied to the CV3 input. For finer adjustments of the filter frequency and/or slope, hold SHIFT while turning the DATA encoder.
The high-pass filter controls are the same as the low-pass filter.
In Bandpass Filter mode you can adjust the cutoff frequency (F), slope (S), bandwidth (W) and resonance. To adjust the filter cutoff frequency, press and hold the SHIFT button while pressing the CH1 button (it will light up) and turn the DATA encoder to change the cutoff frequency. The control assigned to the encoder is shown in a circle around the relevant letter in the top right of the display. The cutoff frequency can also be controlled by a CV applied to the CV1 input. To adjust the filter slope, press and hold the SHIFT button while pressing the CH3 button (it will light up) and turn the DATA encoder to change the slope. The slope can also be controlled by a CV applied to the CV3 input. To adjust the bandwidth, press and hold the SHIFT button while pressing the CH5 button (it will light up) and turn the DATA encoder to change the bandwidth. The bandwidth can also be controlled by a CV applied to the CV5 input. For finer adjustments to the filter frequency, slope and width, hold SHIFT while turning the DATA encoder.
The controls for the Notch (Band Reject) filter are the same as for the Band Pass filter. All filter and resonance settings can be saved as a preset. To save a setting, press and hold the DATA encoder for 3 seconds to enter the save menu. The preset save menu is the same as the one in Filter Bank mode. To exit the filter menu, press the BACK button.
Press and hold the SHIFT button and the corresponding BAND button to go to the clock settings. The settings are INTERNAL/EXTERNAL clock, BPM for the internal clock, CV source and CV gain. The selected function will light up and the change will be shown at the top of the display. To select the clock source, select the CLK setting at the top left of the display and turn the DATA encoder to select the desired mode (INT or EXT). If the internal clock mode is selected, you can change the BPM. Select the BPM setting next to the CLK setting and turn the DATA encoder to adjust the BPM. The BPM can be changed in increments of 10 BPM, but finer adjustments can be made by holding SHIFT and turning the DATA encoder. The next option is CV SOURCE. Here you can choose between a single CV applied to the CV1 input and all CVs. In CV1 mode the modulation works in a shift register fashion, with each clock pulse the CV applied to the CV1 input is passed to the next bandpass filter, and when filter 10 is reached the cycle starts again with the first filter. In ALL CV mode the modulation works in a sample and hold fashion. Apply multiple CVs to CV inputs 1-10 and as each clock pulse occurs the CV will be frozen in its momentary state until the next clock pulse appears. The final setting in Clock mode is the CV Attenuator to change the CV level. The gain setting can be adjusted from 0-2. Press the BACK button to exit Clock mode.
If you have several presets stored, they can be played sequentially as a "Song". There are 4 different PLAY modes, accessed by holding SHIFT.
CLK – With each rising clock edge the filter bank switches to the next preset in the memory list.
RND-CLK – On each rising clock edge, the filter bank switches to a random preset in the memory list (but not the currently active preset).
Presets are switched via the CV – CV1 input. Range 0V to 10V mapped to 128 presets, approximately 1V per preset. Presets are switched instantly with no CLK input.
CV-CLK – Similar to CV mode, but requires a CLK edge to switch to the next preset.
Hold SHIFT and press the corresponding lit BAND button to select a mode. Press the bottom right button (it will flash) to begin playing the sequence. The PLAY button will continue to flash to indicate playback is active.
By holding SHIFT you can also configure the morph settings. Here you can set whether the presets change discretely or smoothly. Hold SHIFT and press the ENCODER to toggle morphing on/off. Turn the encoder to adjust the time the morph takes. Press the BACK button to exit the PLAY menu.
All saved presets (Filter Bank, VCF, Dynamic EQ + Resonance settings) can be instantly recalled during a performance. To load a preset, turn the DATA encoder to select the preset and press the encoder to load it. Presets in the list have a mode indicator in the right column to identify if it is a Filter Bank (FB), Dynamic EQ (DYN) or Multimode Filter (FILT) preset. The number on the left determines the playback order in PLAY mode. Press and hold SHIFT to access three options: Delete (DEL), Rename (REN) and Move (MOVE). These are the options to delete, rename or move the preset in the list respectively. When MOVE is selected, the selected preset is highlighted and you can select a new location in the list with the DATA encoder. Note that placing a preset in a different slot will swap places with the preset in that slot. Press the BACK button to exit the LOAD menu.
The module has a handy feature called the Spectrum Analyzer, which displays the frequency content of the input audio signal. The Spectrum Analyzer has the option to display bar peaks for better visualization of the spectral content. To turn this ON/OFF, hold SHIFT and press the encoder. Similarly, hold SHIFT and turn the encoder to change the fall time of the bar peaks. Additionally, if you want to change the scale of the X-axis (LIN or LOG), hold SHIFT and press the corresponding lit BAND button. To exit the Spectrum menu, press the BACK button.
In Dynamic Equalizer mode, the module detects the spectral content of the audio signal and automatically cuts higher frequencies or boosts lower frequencies relative to a manually settable threshold. Turn the DATA encoder to set the cut threshold. Press the DATA encoder to enable the Dynamic Equalizer. Press and hold the SHIFT button and press the DATA encoder to enable frequency boost. This slightly boosts frequencies below the threshold. Using the Dynamic Equalizer without boost makes it easier to find your resonance "sweet spot". Enabling boost will enhance the spectral composition of your sound (be careful of resonance when boosting!). Press the BACK button to exit the Dynamic Equalizer menu
The Configuration menu allows you to change the master settings of the module, including the OLED display settings, CV inputs, the response curve of the resonance potentiometer, the feedback loop of the filter bank, etc. Turn the DATA encoder to navigate through the submenus, then press the DATA encoder to select the relevant submenu.
The INFO section of the configuration menu shows the firmware version, bootloader version and even the manufacturer of the module. To do a FACTORY RESET, press and hold the BAND 10 button for 2 seconds and a pop-up menu will appear asking you to confirm or cancel. Press the illuminated button corresponding to CANCEL (Band 1) or RESET (Band 7). To exit the INFO menu, press the BACK button.
The DISPLAY section allows you to adjust the brightness of the OLED display, the dimming time of the display when no operations are performed, and the screen saver on/off. Turn the DATA encoder to select the parameter you want to change and press the DATA encoder to access the setting. Then turn the DATA encoder to adjust the setting. Press the BACK button to return to the parameter selection. Press the BACK button to exit the DISPLAY menu.
The CV Input Settings section allows you to select the expected CV input signal amplitude for full span operation as well as set the master attenuation of the Filter Bank Band Pass Filter and Resonance CV inputs. Rotate the DATA encoder to select the parameter you wish to modify. To select CV RANGE, press the DATA encoder. Available CV ranges are [-5V - +5V], [-10V - +10V], [0 - +5V], and [0 - +10V]. To adjust the master attenuation of the Filter Bank Band Pass Filter CV inputs, press and rotate the DATA encoder to set the desired gain level. Press the BACK button to return to the CV Settings submenu. The settings for the Resonance CV input are the same as the Filter Bank CV input settings. Press the BACK button to exit the DISPLAY menu
The RESO setting menu allows you to select the response curve for the resonance potentiometer. Turn the DATA encoder to select the desired curve. Available options are: Balanced, High only, Low only, Linear, Log, and Exponential. Press the BACK button to exit the RESO menu.
The FEED menu allows you to select the bandpass filters involved in the resonance feedback loop. Each filter resonates at a different frequency, so the filter you select will have a very different impact on the sound. You can select the relevant filter by pressing one of the bandpass filter selection buttons, or press the DATA encoder to select all filters at once. Resonance is off when the knob is in the 1 o'clock position, and inverted by turning it further counterclockwise. Note that the feedback setting is not saved with the preset. Press the BACK button to exit the FEED menu. Note! When the resonance source is set to a single channel, the counterclockwise position does not attenuate the input exactly, creating a unique resonance that is less predictable. Have fun experimenting!
When an official firmware update is released by Erica Synths, you can update Resonant FB via the audio bootloader. You can check the current firmware version in the information section accessible from the settings screen. Download the firmware update audio file from the Erica Synths website and connect the headphone output of your computer to the AUDIO IN input of Resonant FB. Turn off Resonant FB and turn it back on while holding down the CH9 and CH10 buttons, which will put Resonant FB into firmware update mode. Turn the IN LVL knob fully clockwise. Play the firmware update audio file and check the LEVEL indicator. The level should fluctuate in the upper half of the bar. If the level is too low, increase the computer volume, if it is too high, decrease the volume. Alternatively, turn the DATA encoder to adjust the gain of Resonant FB. If the level is not in the proper range, the update may fail, but you can adjust the level and try again. The audio file must play without interruption for the update to be successful. Press the DATA encoder, the CH10 button, and the SHIFT button at the same time and see what happens!
