4ms Company Spectral Multiband Resonator User manual

Spectral Multiband Resonator
from 4ms Company
Eurorack Module User Manual v1.0.1b ( ctober 2015)
The Spectral Multiband Resonator from 4ms Company is a versatile resonant filter with six bandpass
resonators/filters having variable frequency quanti ed to scales or 1V/oct tracked, and variable Q/resonance.
Stereo inputs/outputs and a host of unique features allows for many uses:
•Create beautiful moving chord structures, quanti ed to selectable scales
•Process audio like a classic filter bank/EQ
•Pluck/ping/strike to ring like a marimba, gong, or membrane
•Beat-sync to an audio track, triggering modular sounds in sync with original audio
•Vocode, outputting spectral data to a second SMR
•Re-mix tracks
•Harmoni e to audio
•Quanti e audio to built-in or custom programmed scales
•...and much more
Check 4msCompany.com for updates to the manual

Basic features:
•Six resonator/filter channels
•Variable "Q" (Resonance) ranges from classic band-pass to highly resonant ringing
•Ring of 20 full-color lights displays the channel frequency
•Channel 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 channels are rotated or spread
•Lock buttons prevent each channel from changing in frequency (resonance can also be locked)
•Freq Nudge knobs create de-tuning effects, or are useful for picking out a precise frequency
•Frequency CV input (1V/octave) for even and odd bands (flip switch selects single or multiple channel control)
•Stereo inputs and outputs stagger the bands into evens/odds for an immersive stereo field
•Spectral content outputs for each channel (Env Out jacks) allow for vocoding (spectral transfer)
° Switch selects Fast or Slow tracking speeds, or trigger outputs
° Trigger output mode fires a trigger when envelope crosses a threshold: 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
•Scale banks for Western, Shrutis (India), Chromatic, Diatonic, Micro-tonal 17-note/octave, Gamelan (Pelog and
Slendro), Bohlen-Pierce 13-note tritave, Wendy Carlos's Alpha and Gamma scales. Both equal tempered and just
intonation tunings
•Rotation/Spread moves about an entire bank, or can be limited to a single scale
•White noise is normali ed to the inputs, so the SMR can be used without an external signal
•Settings and LED color scheme can be saved and recalled in multiple banks
Controls and jacks:
•Filter channel level
° Six sliders set the level of each filter
° White light on each slider indicates filter level (flashes for clipping)
° Six CV inputs for level of each filter. (0 to +5V). Slider attenuates CV on jack
•Twenty full-color LEDs indicate which filters are assigned to which channel
° Colors on light ring match colors of Env Out LEDs
° Brightness of each light shows level of each filter
•Resonance (Q)
° Res (Q) CV jack (0 to +5V)
° Knob (offsets CV jack)
•Stereo input and output (divided into even/odd bands)
° Odd input jack and Even output jack serve as Mono in/out
° Clipping LED between IN jacks flickers when input is clipping (about 20Vpp or +/-10V)
•Rotation shifts frequency pattern up or down
° Rotate Clockwise trigger input (2V threshold)
° Rotate Counter-clockwise trigger input (2V threshold)
° Rotate CV jack maps any waveshape to a rotation pattern (0 to +5V)
•Spread sets the interval (spacing) between channels
° Spread CV input jack (0 to +10V)
° Knob (offsets CV value)
•Morph sets speed of cross fading rotating, spreading, or scale selection
° Morph CV input jack (0 to +10V)
° Knob (offsets CV jack)
•Scale CV input jack selects scale from current bank (0 to +5V)
•Six Env Out jacks: CV outputs that 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
° 0 to +8V output
•Six Lock buttons lock the frequency of each channel
° Button is lit when locked
° Rotation, Spread, Freq Nudge, Scale, and Bank will not change when locked
° Turning Q knob while holding a lock button also locks the Q value (button flashes to indicate Q-lock)
° Lock jack: locks/unlocks even or odd channels when triggered (2V threshold)
•Freq jacks: 1V/oct frequency input jacks for even and odd channels (10 octave range, 0 to +10V)
•135 | 1 switch selects if Freq jack, Freq Nudge knob, and Lock jack control all odd channels (1/3/5) or just channel 1
•246 | 6 switch selects if 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 channels to rotate into the next/previous scale each time they rotate fully around
Note: The active voltage range for each jack is given. All jacks are tolerant of signals from -12V to +12V, but signals outsi e
the active range are clippe to the active range. For example, on a jack with an active range of 0 to +5V, a voltage of -4V is
seen by the SMR as 0V, an +8V is seen as +5V.
2

Advanced features:
•Program your own scale:
°The frequency of each of the 20 notes can be assigne by setting the octave, the semi-tone, an coarse an fine
micro-tone.
°Up to 11 scales can be save permanently in the user bank
•A just color scheme of the lights:
°Pick a pre-programme color scheme or create your own using the sli ers to set re /green/blue values.
°Custom color schemes can be save permanently
•Save your settings in one of six Settings Slots.
°Note position, scale an bank selection, Q value, lock settings an color scheme can be save an recalle on the
fly.
°On startup, the SMR loa s settings from the last save bank.
•Optional alternative filter type
°More exponential ecay an ifferent timbral qualities when plucke .
°Freq jacks no longer track 1V/oct in this mo e
•Sli er LEDs can be selecte to isplay clipping an level, or just level
•Firmware can be up ate by playing enco e au io files from a computer into the SMR
Specifications
•26 HP Eurorack format module
•16-to-16pin eurorack power cable (included)
•0.95” (24mm) maximum depth
•Power consumption:
◦+12V rail:
▪86mA max (jumper set to 5V)
▪110mA max (jumper set to 12V)
◦-12V rail: 28mA max
◦+5V rail:
▪25mA (jumper set to 5V)
▪0mA (not use when jumper set to 12V)
Jumper
VSEL jumper: +5V VSEL jumper: +12V
Most modern modular power supplies provide power on the +5V rail. It's recommended to use the +5V rail when available. If
your system does not provide +5V, or if your +5V rail is noisy, the SMR can be set to generate an internal 5V from the +12V
rail by moving the jumper to +12V as shown above.
3

Getting started: your first patch
The easiest SMR patch is making droning chords. Only one cable is needed! Set up the SMR as shown:
•Turn all the Lock buttons off (press any button that's lit to turn it off)
•Flip Scale Rotation switch off (down)
•Freq Nudge to 0% (both knobs, in the upper left and upper right)
•Res (Q) knob to 100%
•Spread to 0%
•Morph to about 50%
Patch the black OUT jack into your mixer (unpatch all other jacks).
Turn RES (Q) to 100%
There are six sliders. Each one controls the volume of a filter/resonator channel. Push down all six sliders, then slide
each one up, one at a time. You should hear a pitch fade up in volume. Each slider controls a different frequency.
As you adjust the slider, watch the light ring. Each slider is associated with a color. The color gets brighter on the light ring
as the slider moves up and down. Each of the 20 spots on the light ring is associated with a pitch (a frequency, or a musical
note).
Turn the ROTATE knob one click to the right. Hear how the pitches shift up and the lights rotate one step clockwise. Click
the ROTATE knob down, hear how the pitches shift down and the lights rotate counter-clockwise. Keep spinning the knob so
that the lights move past 12:00 (due north, marked by a tick mark on the light ring). Notice how the pitches go to the top and
then start at the bottom. By rotating and pushing different sliders up and down, you can make different chords.
Play with Morph as you continue to turn the ROTATE knob. Morph sets the speed at which rotation happens. With Morph
at 100%, when you turn the ROTATE knob the SMR will slowly fade from one position to the next. With Morph at 0%, the
SMR will instantly jump from one position to the next.
Play with Spread, which controls the number of empty spots in between each channel. With Spread at 0%, the channels
occupy adjacent spots on the light ring. As you turn Spread up slowly, the channels will jump to having one spot between
them, then two spots, then three, etc... As the spacing increases, the channels will get pushed around and eventually the
highest channel will wrap around the lowest.
Play with the Q (Res) knob . The SMR has a digital noise source normali ed to the audio IN jacks. With Q set to 0%, you
should hear a filtered version of this noise. Adjust the sliders, ROTATE, and Spread to bring in different bands of noise. Notice
how as you turn up Q, the output slowly changes from filtered noise towards pure sine waves. This is the effect of a tight
bandwidth (Q) or resonance: only very select frequencies from the noise source are allowed to pass to the output. If you have
a favorite noise module (or any complex sound source), try running it into the input jack(s).
Finally, try running a 1V/oct melody line from a sequencer into one or both Freq jacks. Flip the 135 | 1 and 246 | 6
switches to select which channels are tracked, and which stay steady.
4
TO MIXER

Patching percussion: Marimbas, gongs, and wood blocks
This is a great patch for creating resonant percussive sounds. You need a trigger or gate source. A clock module such as the
Quad Clock Distributor (QCD) or RCD or SCM from 4ms works well. In a live setting, you could use manual trigger/gate
sources such as the FSR-4 from Synthwerks, or the Pressure Points from Makenoise. Another option is a trigger recorder
such as the Tri-ger from Qu-Bit Electronix.
Patch the black “evens” OUT jack into your mixer (un-patch all other jacks). For stereo output, also patch the white
“o s” OUT jack into your mixer an pan it to the left. Pan the black “evens” signal to the right.
Patch your trigger sources into the IN jacks. Two sources with different rhythmic content is ideal, however if you only
have one trigger source, just patch into the “odds” jack. To start, have the triggers firing about once or twice per second.
The odds IN jack goes to channels 1, 3, and 5. The evens IN jack goes to channels 2, 4, and 6. So each trigger source can
strike a chord of three notes.
Listen to how the channels resonate when struck with a trigger or gate, they should sound like a gong or marimba. Adjust
the Q (Res) knob to change how “ringy” the sound is: low Q is like a wood block, high Q is like a large bell.
The amplitude of the triggers also effects the sound, try attenuating or boosting the triggers before they reach the SMR.
Notice that the SMR will be struck on both the rising and falling edge of a gate, so two sounds will be heard for every gate.
Triggers will cause only one sound since the rising and falling edges are very close together.
Adjust ROTATE and Spread to change the pitches of the notes, and play with the sliders to adjust the level of each note.
Input another trigger source into Rotate Trig → or Rotate Trig ←. If you don't have another trigger source, you could input
an LFO or envelope (0 to +5V) into Rotate CV In and the rotation will track the waveshape of the incoming CV.
Play with slowing down the rotation from the external triggers by turning up Morph. Try setting the rotation trigger source
super fast and then turning Morph up and down to adjust the speed of the motion. Morph is a powerful way to limit musical
movement (and it can be CV controlled).
The ROTATE knob is also a button: push and release it, and you will enter SCALE mode.
Notice how the LEDs change: the bottom six LEDs are one color and there should be one LED that's slowly blinking colors in
the top half of the ring. This is SCALE mode. Turn the ROTATE knob and the blinking LED will move: each position in the top
half of the ring represents a different scale (there are eleven). Listen to how each scale is different. You may want to click the
ROTATE knob again to go back to Rotate mode so you can rotate the channels around to hear how the scale sounds. If you
like, patch CV into the Scale CV jack to control the scale selection with another module.
Run CV into the Level CV jacks. Gates from a QCD work great, and you can flip the CV Slew switch to the left to smooth
out the click that happens when a gate snaps up or down. Setting Morph higher when you flip the Slew switch will cause more
slewing to happen, which means very fast CV in the Level CV jacks will be rolled off.
Try running a fast decaying envelope into one or both Freq jacks. Time it to the trigger sources to get membrane drum
sounds. Or try a 1V/oct melody line from a sequencer to track the pitches. Flip the 135|1 and 246|6 switches to select which
channels are modulated/tracked, and which stay steady.
5
Trigger
source #1
Trigger
source #2
TO MIXER

Filtering audio: basic re-mixing
Re-mixing audio tracks often involves highlighting certain instrumentation and getting rid of others. This can be done by
boosting and cutting frequency bands with the SMR. Note that if you're using a line level signal, you need to first boost it to
modular level.
Input a modular level audio signal into the IN jacks (use the odds jack for mono, or both jacks for stereo).
Take the output from the OUT jacks to your mixer (use the evens jack for mono, or both jacks for stereo).
Turn RES (Q) all the way down. Unlock any Lock button that's lit by tapping the button.
Hold down the ROTATE knob while you turn it. The bottom six LEDs should change color, each color represents a
different bank. Keep holding down and turning until the you've selected the deep blue bank. Any bank will work, but the deep
blue bank is nice for re-mixing because the scales are set to common graphic EQ frequencies.
Slide channel 1's slider up and the rest of the sliders down. Turn the ROTATE knob to rotate channel 1 while you listen to
the audio. (If you're in scale mode, click the ROTATE button once to switch to rotate mode – see Rotation section on page 10
for details). Keep rotating until you find a frequency band you want to boost. Adjust the RES (Q) knob to narrow the band and
add resonance if you wish.
You may also want to adjust the left Freq Nudge pot to fine-tune the frequency.
When you find the frequency setting you want, tap the channel's Lock button. This will lock the rotation as well as the
Freq Nudge setting. If you also want to lock the Resonance setting, wiggle the RES (Q) knob while holding down the Lock
button. The Lock button will be lit if the channel is locked, and also flicker if it's Q-locked. If you don't lock the Q, then the
channel's resonance will be controlled by the RES (Q) knob and jack along with all the other channels with unlocked Q.
Repeat this process (steps 5-7) for channels 2-6. Note that for channels 2, 4, and 6 the Freq Nudge knob on the right is used,
while for channels 1, 3, and 5, the Freq Nudge knob on the left is used. Make sure the 135 | 1 switch is set to 135, and the
246 | 6 switch is set to 246 (otherwise the respective Freq Nudge knobs will only control channels 1 and 6).
After setting all the channels to a useful frequency, adjust the mix of the six sliders. Play with adjusting the Q of each channel
(you can hold the Lock button and re-adjust the Q knob to change a Q-locked channel). You can range from essentially a re-
EQ'ed track to harmoni ing, resonant bowl sounds. Since each channel has a different Q value, both sounds can co-exist.
To take the next step, consider running LFOs, envelopes, or clock gates into the Level CV jacks.
Consider rotating some channels while keeping others still. One technique is to manually unlock channels, apply rotation, and
then re-lock them. To maintain the Q-lock setting while unlocking rotation, hold the Lock button for 2 seconds to unlock.
When one or more channel is unlocked, turn the ROTATE knob or use a trigger into the Rotate Trig jacks. The trigger could
even be synchroni ed with the signals you're running into the Level CV jacks. Or run an LFO or envelope into the Rotate CV
jack. Play with Morph to make the rotation slower or faster. Another idea is to run a slow LFO into the Freq jacks, to create a
filter sweep effect.
Keep this patch going, and continue on to the next patch idea...
6
TO MIXER
Audio
track

Beat syncing: advanced re-mix techniques
This patch idea is a powerful way to sync your modular system with an external audio source-- whether it's a pre-recorded
track or a feed from other instruments being played live. The basic idea is to convert different frequency bands into trigger
outputs, with the rhythm of the triggers matching the rhythm of the original audio's instrumentation.
Start with step to of the Re-mix patch on the previous page (patch audio inputs and outputs, turn down RES [Q] and
select the EQ bank).
Set the 135 | 1 switch to 135, and the 246 | 2 switch to 246.
Set Fast | Slow to the center position (triggers), and set Post | Pre to Post. Set Scale Rotation down.
Let's say you have a dance track with a kick, snare, hi-hat, and some melody lines happening. You can use the SMR to
convert each kick drum hit into a trigger output, which you can use to trigger your own kick drum (or clock your master clock,
or trigger anything on the modular). Start by patching the ENV OUT jack for channel 1 into something that makes sound when
triggered.
Turn down all the sliders and bring up the slider for channel 1 to around 50%. Listen to the SMR's output as well as the
externally triggered module. You might want to monitor the input audio, too (use a mult or splitter before the SMR).
There are four parameters to play with to get beat-synced trigger outputs: Rotation, Freq Nudge, Q, and Level (steps 9-12):
Turn ROTATE so that channel 1 is triggering the external module whenever the kick drum hits. Probably for a typical kick
drum, channel 1 should be on the 2nd, 3rd, or 4th note (it depends on the pitch of the kick you're trying to tune into).
Set Freq nudge to dial in a frequency in between two rotation spots.
Turn Q up to narrow the band. Around 50% is a good place to start for syncing to drum sounds.
Set the Level slider to set the threshold at which the trigger fires. If you set it too high, the Env Out light will stay on, and it
it's too low it'll stay off. If the slider seems to have no effect, double-check Post | Pre is set to Post.
When you get a good lock, press and hold the lock button while you wiggle the Q knob, the release. Press the Lock button
again. Now the channel should be locked and Q-locked. Its Lock button will be on with a quick periodic flicker off.
Repeat 9-12 for the next channel, perhaps do the snare or a hi-hat next. Make sure the channel is locked before you move to
a new channel, or else you'll lose your settings.
Advanced: Use an external CV source (try a SISM) into the Level CV jack with the slider all the way up. This way you can
mute/unmute a channel using the slider and not lose your level setting (since it's set on the SISM).
When you like what you hear, save your settings. Hold the ROTATE button down for 5 seconds until the Lock buttons flash
and an animation appears on the slider LEDs. Release the ROTATE button. If you want, you can spin the ROTATE knob to
choose a new color scheme for these settings. Each Lock button represents a Settings Slot (1-6). If you wanted to load a slot
you could tap any of the Lock buttons. But in this case we want to save our settings, so press and hold any Lock button for 2
seconds. The SMR will pause for a fraction of a second while it saves all the settings into that slot. The next time you power
on the SMR, these settings will be loaded automatically.
7
Audio
track
TO MIXER

Vocoding and other spectral transfers
Using two SMR's, you can create spectral transfer effects. One type of spectral transfer is known as Vocoding, which is
classically used with human speech and a sawtooth oscillator.
Patch a human speech audio signal into the first SMR's odds IN. Use a vocal sample, or a microphone with an audio
input module. You are not limited to just using human speech, but it's a great way to start playing with this technique.
Patch the carrier signal into the second SMR's odds IN. Use a sawtooth VCO, or perhaps an FM'ed VCO. You also could
use another sample or a complex sound from another patch.
Patch the second SMR's evens OUT to your mixer so you can listen. You also may wish to patch the first SMR's evens
OUT to the mixer for monitoring the modulating signal.
Flip Post | Pre to Post on the first SMR
Patch all six Env Outs jacks on the first SMR to the six Level CV jacks on the second SMR. If this is your first time, keep
them in the same order (1->1, 2->2...)
Play with the rotation, spread, scale and bank of both SMRs. You might want to start in the blue bank (graphic EQ) and
with the channels positioned as shown in the diagrams above.
Play with the RES (Q) of both SMRs
To fine-tune the patch, follow the technique outlined in the Re-mix patches, setting the note, scale, bank, and resonance of
each channel on both SMRs.
Usage
Channels: Six resonant filters
The core of the SMR is six resonant band-pass filters. The six channels take their inputs from the audio IN jacks, and their
outputs are mixed together using the sliders and Level CV jacks. The mix is then fed to the audio OUT jacks. The audio IN
jacks are normali ed to a digital noise source, so no input is necessary.
Channel color
Each channel is given a color. By default, channel 1 is blue, channel 2 is cyan, channel 3 is green, channel 4 is pearl, channel
5 is orange, and channel 6 is rose. The colors can be changed by editing the Color Scheme (see Advanced Features). The
color is shown on the light ring and also on the Env Out lights. The easiest way to see the color of a channel is to glance at its
Env Out light's color. Another way is to slide its slider up and down and see which light on the light ring is going dim and bright
(you must be in Rotate mode).
Digital noise source
A digital noise source is normali ed to the odds IN jack. With nothing plugged into the odds IN jack, the SMR will
filer/resonate this digital noise source. The noise source repeats its pattern, and the frequency content fluctuates.
Stereo/mono operation
For mono operation, patch into the IN and OUT jacks circled in black (odds IN, evens OUT).
8
To mixer
(main out)
VCO
(carrier)
peech
(modulator) To mixer
(monitor)

The evens IN jack is normali ed to the signal on the odds IN jack. When just the odds IN jack is patched, it feeds all six
channels. When both jacks are patched, the odds jack feeds channels 1, 3, and 5, while the evens jack feeds channels 2, 4,
and 6.
The odds OUT jack is normali ed to the signal on the evens OUT jack. When just the evens OUT jack is patched, all six
channels are heard. When both jacks are patched, channels 1, 3, and 5 feed the evens OUT jack, and channels 2, 4, and 6
feed the odds OUT jack.
Frequency
Each channel is a band-pass filter with a center frequency. The frequency is controlled by several things:
•Note on the scale, shown by the light ring and controlled by Rotation and Spread
•Scale and bank selection
•Freq Nudge knob
•Freq jack (1V/octave)
Each of these elements is discussed in detailed below.
Notes, scales, and the light ring
The light ring displays what frequency (or note in the current scale) each
channel is assigned to. Notice there are 20 spots on the light ring. Each
spot represents a particular frequency, or note. The entire ring of 20 notes is
called a scale. A mark at the top center (12:00) indicates the first note,
which is typically the lowest pitch. The frequencies typically increase as you
rotate clockwise. (We say “typically” because you can create a custom scale
that places any frequencies in any order)
The diagram on the left is an example scale that ranges from a low A note
to an E note about ten and a half octaves higher. Channel 1 is set to 55H ,
channel is set to 82.5H , channel 3 is set to 110H , etc.
This happens to be the default scale when the SMR is first run. The SMR
has many other scales representing a variety of musical types, both modern
and historical, common and esoteric, and custom. See the next page for
how to change the current scale and bank.
One feature of the SMR is that the six filters always are assigned to unique
channels. That is, two channels cannot occupy the same spot on the light ring. This is an intentional feature because richer
sounds result from mixing together filters of different frequencies. However, if you want two channels to be at the same
frequency (for instance with a stereo input where you want the same filtering to happen to both left and right) you can rotate
them to adjacent spots on the light ring and turn Freq Nudge all the way up for the lower channel. Alternatively, you can
program a custom scale with duplicate frequencies.
Freq Nudge knobs
There are two Freq Nudge knobs, one for the odd channels, and one for the even channels. A switch selects whether the
Freq Nudge knob controls all the odd (even) channels or just channel 1 (6). Freq Nudge's default position is at 0%, this
means the frequency is not nudged and the notes in the current scale will be unaffected. Thus if you wish to keep the
channels in tune with the scale as it was programmed, keep the Freq Nudge knobs all the way down. As you turn Freq Nudge
up, the frequency will bend towards the next note in the scale. At 100%, the frequency will be the same as the next spot on
the light ring. Thus, you can dial in any frequency between two notes on the scale. Note: There is a hi en 21st note in each
scale, so nu ging a channel at note 20 will ben it up towar s note 21, not own to note 1.
Locking a channel also locks the Freq Nudge setting. So you can nudge a channel up to an exact frequency and then lock it,
continuing to use Freq Nudge to nudge other channels without effecting the locked channel.
Freq jacks
There are two Freq jacks for controlling the frequency of the channels. Each one is tuned to 1V/octave.
Note: in Firmware version 1 (shipped prior to October 3, 2015), the response is 1.5V octave. Firmware version 2 and
later is 1V octave.
Like Freq Nudge, a switch selects whether the jack controls all odd (or even) channels or just one channel (1 or 6).
The jacks have a 10 octave range, so a voltage range of 0V to +10V is accepted. Since negative voltage on this jack does
nothing, the Freq jack only makes the pitch go up, it will not lower the pitch. Thus, the note and scale setting for each channel
defines the lowest pitch.
In most cases, you should be able to passively mult a 1V/octave signal into both Freq jacks (it depends on the module
supplying the 1V/octave signal).
In order to increase stability, the Freq input rolls off high-frequencies. Some classic FM sounds can be achieved by inputting
low audio rate signals into the Freq jack, but as the frequency increases the effect decreases.
9

Q (Resonance)
FFT (Spectral Plot) of SMR output with white noise input
Narrow Q: RES knob at 100% Wide Q: RES knob at 10%
Each channel has a resonance setting (Q). When the Q/resonance parameter is set high, the six channels act more like
resonators rather than what we normally think of as “filters”, in that they produce a somewhat pure tone or pitch in the
presence of even a tiny bit of that frequency on the audio input. The digital noise signal that's normali ed to the input contains
all frequencies, so no matter what note is assigned to a channel, it will output sound.
Interestingly, a trigger or gate also contains all frequencies, so sending a pulse into the audio input causes all channels to
make a sound. Varying the Q value changes the clicky-ness and ringy-ness of the sound, as well how rapidly the resonant
sound decays (see scope shots below). If the pitches of the six channels are tuned to different notes in a scale, chords can be
played (See Scales and Banks, below). If the pitches are controlled using the 1V/octave inputs, then the SMR acts like a six-
voice VCO.
Trigger fe into SMR au io input (purple trace). Resonant soun at output (blue trace). Gate fe into SMR
RES (Q) at 40% RES (Q) at 75% RES (Q) at 100% Both rising and falling edges
of gate signal causes a
resonant sound on the output
When a channel is tuned to a particular frequency, the SMR will be quiet until that frequency appears on the input, at which
point it will make a resonant sound exactly at the tuned frequency. Try running a sine-wave output of a VCO into the SMR and
sweeping the VCO pitch up and down. As the VCO pitch comes close to the frequency of any of the channels, that channel
will ring and continue ring for a bit after the VCO has left that frequency.
When the resonance is low, the six channels act more like band-pass filters. Each slider controls the volume of that band. If
the bands are spaced evenly across the range of human hearing then the SMR will function like a graphic EQ. If the bands
are rotated or swept up and down in frequency, then the SMR will function somewhat like a traditional band-pass VCF.
Rotation
Rotation is a major feature of the SMR. The light ring is important to watch when learning about rotation. Rotation can happen
in one of two directions: clockwise or counter-clockwise. When rotated, all six channels move in the same direction, and the
six lights on the light ring will fade to the next adjacent spot. If a channel is locked, it won't rotate (see Locks, below). If a
channel is rotated such that it would land on top of a locked channel or another channel moving in the opposite direction, then
it will move through the locked or moving channel and stop on the other side.
Rotation is closely linked to Morph, which sets how quickly (or slowly) rotation can happen (see Morph section below). No
matter how much rotation you tell the SMR to do, it will only go as fast as the Morph setting allows. Rotation is also queued,
so if you quickly turn the ROTATE knob ten notches to the right and have a very slow Morph setting, the SMR will start
rotating all the channels one step at a time until it's rotated a total of ten times. Each of the ten rotations will happen at the
Morph speed. Reversing direction clears the queue, so if you want the SMR to stop rotating, you can turn the ROTATE knob
one click in the other direction. The SMR will forget the remaining rotations in the queue and just rotate once in the new
direction.
10