Spectral Multiband Resonator [SMR]

August 25, 2020: v5.1.1 firmware available (minor bug-fix)

Version 5.1.1 zip file Version 5.1.1 wav file [LOUD!] Manual 1.1.1

The Spectral Multiband Resonator from 4ms Company is an innovative resonant filter which can process audio like a classic filter bank, ring like a marimba when struck, vocode, re-mix tracks, harmonize, output spectral data, quantize audio to scales, and much more...

A gorgeous ring of colored lights displays the frequency of each filter, as well as the levels and current scale selection(s).


About the SMR:

At a glance, the SMR works like a normal six-band graphic EQ: six frequency band-pass filters are mixed together using sliders. Resonance/Q is variable, which changes the "ringy-ness" or width of the bands.

But here's where comparison stops. The frequency of each channel is treated like a note in a scale, and the six bands form a chord. Spin the Rotate knob and the "notes" circle around the scale, rotating back to the bottom once they've reached the top. Adjust Spread and the distance (interval) between each note changes. Triggers for up/down motion, CV inputs for sequencing and scale selection allow for flexible control with external modules. Morph, which automatically cross-fades between frequencies, together with variable Slew allows rhythmic clocks drive the SMR as a variable-speed evolving resonant filter.

At maximum Resonance/Q, the SMR can be struck like a gong or marimba by inputting clocks or triggers. The frequency of each channel is quantized to a scale: beautiful chords, ethereal tones and eerie ambiance flows easily. With lower resonance, the SMR can pull out particular frequency bands, and sweep these across the spectrum.

Two 1V/octave Frequency jacks allow for tracking even and/or odd bands and creating floating melodies over evolving chord bases, or complex percussive membrane sounds.

Save your settings into one of six storage banks, and recall on the fly. On startup, the SMR instantly jumps to the last saved settings. The color scheme of the lights can be adjusted, so if you prefer all white lights on your modular, you can have that (or all red, or rainbows, pastels, etc..)!

Basic Features:

  • Six filter channels, selected from twenty active filters displayed on the light ring
  • Variable "Q" (Resonance) ranges from classic band-pass to ultra-resonant ringing
  • Ring of 20 full-color lights displays the filter frequencies
  • Filter frequencies move about the scale using Rotation and Spread
  • Rotation "spins" the frequencies around the scale
  • Spread controls the gap between neighboring bands
  • Morph creates a variable speed cross-fade when the filter frequencies change
  • Lock buttons prevent each channel from changing in frequency (resonance can also be locked)
  • Freq Nudge knobs for creating de-tuning effects, or honing in on an exact frequency
  • Frequency CV input (1V/octave) for even and odd bands (flip switch selects single or multiple channel control)
  • Stereo ins and outs stagger the bands into evens/odds for an immersive stereo field
  • Spectral content outputs for each channel (Env Out) allow for vocoding (spectral transfer)
  • Fast or Slow tracking speeds for Envelope CV ouptuts, or selectable Trigger output mode is useful for extracting a beat from music
  • Sliders and CV jacks control each filter's level
  • Slew switch applies slew-limiting to the CV level jacks, which prevents clicking from clocks or triggers
  • Each bank has 11 scales of 20 frequencies/notes each.
  • User-programmable scales (select octave, chromatic note, and microtonal adjustments for each note in the scale)
  • Scale banks for Western, Indian, Chromatic, Micro-tonal, Equal tempered, Just intonation tunings
  • Rotation/Spread moves about an entire bank, or can be limited to a single scale
  • White noise is normalized to the inputs, so the SMR can be used without an external signal
Advanced features
  • Program your own scale. The frequency of each of the 20 notes can be assigned by setting the octave, the semi-tone, and coarse and fine micro-tone. Up to 11 scales can be saved permanently in the user bank
  • Adjust color scheme of the LEDs. Pick a pre-programmed color scheme or create your own using the sliders to set Red/Green/Blue values. Custom color schemes can be saved permanently
  • Save your settings in one of six parameter banks. Note position, scale and bank selection, Q value, Lock settings and color scheme can be saved and recalled on the fly. On startup, the SMR loads settings from the last saved bank.
  • Optional alternative filter type for a more exponential decay when plucked and different timbral qualities. Freq jacks no longer track 1V/oct in this mode.
  • Slider LEDs can be assigned to display level for each channel (combination of slider position and CV on the jack), or clipping for each channel.

Electrical and Mechanical Specifications:
  • Module Size:
    • 26HP Eurorack module
    • 0.95" module depth (24mm)
  • Power consumption:
    • +12V rail: 86mA maximum (110mA max when jumper set to +12V)
    • -12V rail: 28mA maximum
    • +5V rail: 25mA maximum (0mA [not used] when jumper set to +12V)
  • Controls, Inputs and Outputs:
    • Six sliders control level of filter
      • White LED on each slider indicates gain (selectable to indicate clipping)
    • Six CV inputs for level of each filter (slider attenuates CV on jack)
    • Twenty full-color LEDs indicate which filters are assigned to which channels
      • Color on LED ring match colors of Env Out LEDs
      • Brightness of each LED shows level of each filter
    • Q (Resonance) knob
    • Q (Resonance) CV jack
    • Stereo input and output (divided into even/odd bands)
      • Odd input jack and Even output jack serve as Mono in/out
    • Rotate Clockwise and Rotate Counter-clockwise trigger jacks
    • Rotate CV input jack maps any waveshape to a rotation pattern
    • Scale CV input jack selects scale from current bank
    • Spread knob sets the interval (spacing) between channels
    • Spread CV input jack
    • Morph knob sets speed of cross fading rotating or spreading
    • Morph CV input jack
    • Six CV outputs follow envelope of frequency content per band
      • Fast | Slow switch selects envelope tracking speed, or Trigger output mode
      • Pre/Post switch selects whether Env Out jacks track the filter before or after the slider attenuates
    • Six Lock buttons lock the frequency of each channel
      • Button is lit when locked
      • Turning Q knob while holding a lock button also locks the Q value (button flashes to indicate Q-lock)
      • Lock jack toggles lock status of even or odd channels
    • 1V/oct Frequency input jack for even and odd channels
    • Odds Switch selects if 1V/oct Freq jack, Freq Nudge knob, and Lock jack control all odd channels (1/3/5) or just channel 1
    • Evens Switch selects if 1V/oct Freq jack, Freq Nudge knob, and Lock jack control all even channels (2/4/6) or just channel 6
    • Slew switch enables slew-limiting of incoming CV on the level CV jacks (click and pop prevention).
      • Amount of slew limiting is proportional to Morph setting at the time the switch is flipped on.
    • Scale Rotation switch enables filters to rotate into the next scale each time they rotate fully around
Included with the SMR:
  • 16-to-16 pin power cable
  • 4 M3 Knurlie screws