Intellijel Atlantis User manual

Atlantis Manual
Atlantis
Dual Oscillator Subtractive Synth Voice
Manual Revision: 2017.09.25

Atlantis Manual
Table of Contents
Table of Contents
Overview
Basic Features
Sound Generators
Filter
Modulators
Mixing and Output
Installation
Before Your Start
Installing Your Module
Getting Started
Quick Start
Make a sound
Audition the waveforms and filter types
Modulate the filter
Add an envelope
Try a little FM
Use a sequencer (or CV keyboard)
Basic Architecture
VCO Overview
MIX Overview
VCF Overview
VCA Overview
ENVELOPE Overview
MOD Overview
Panel Reference
VCO
Controls
Inputs and Outputs
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Atlantis Manual
MOD
Controls
Inputs and Outputs
MIX
Controls
Inputs and Outputs
VCF
Controls
Inputs and Outputs
ENV
Controls
Inputs and Outputs
VCA
Controls
Inputs and Outputs
Tips, Terms & Techniques
Noise
Sample & Hold
FM
Sub Osc
Signal Flow
Technical Specifications
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Atlantis Manual
Overview
Atlantis is a complete analog, monophonic synthesizer voice in a single, skiff-friendly
eurorack module. It contains a carefully matched selection of the most desirable subtractive
synthesis components including: two analog oscillators (VCOs); a sub oscillator; a noise
generator; a multimode, self-oscillating resonant filter (VCF) capable of both 2-pole and
4-pole operation; a 4-stage ADSR envelope; a mixer; a voltage controlled amplifier; and an
overdrive circuit.
These components are all pre-connected behind the front panel, enabling Atlantis to
generate sound without patch cables. Furthermore, these normalized routings can be
changed instantly using any of the numerous routing switches sprinkled across the Atlantis’
front panel. This allows for all manner of useful techniques, such as pulse width modulation,
oscillator sync, linear and exponential frequency modulation (FM), low frequency (LFO)
capabilities, and even sample & hold. Musicians can thus create a tremendously wide sonic
palette without ever connecting a patch cable.
For those seeking maximum sonic control, patch points are provided to all these
components — meaning you can reconfigure Atlantis’ architecture in any way you please —
including the ability to route voltages to or from any other eurorack modules in your system.
In this regard, Atlantis becomes not just a single synth voice, but a collection of independent
modules. Need to filter the sound coming from that Intellijel Shapeshifter? Patch it into
Atlantis’ filter. Want some weirdly slewed pitch wobble injected into one of the oscillators?
Patch in an Intellijel Noise Tools.
So what is Atlantis? It’s all of the following:
● A fully featured, fixed-architecture synth that you can happily use without patch cables,
just like many traditional synthesizers.
● A semi-modular synth that enables you to override the various normalled connections,
and reroute the signal flow for experimental sound design.
● An extensible synth that allows you to enhance its sonic palette by patching in external
modules to further shape and define your sound.
● A collection of individual, high-quality synth modules — ready to combine with any and
all other modules in your eurorack system.
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Atlantis Manual
Basic Features
The following is a quick breakdown of Atlantis’ various synthesizer components, patching
and routing options:
Sound Generators
● VCO (primary): triangle core with Hard Sync, Octave switch, Linear/Exp FM and PWM.
● MOD (second VCO): triangle core with a Hard Sync option, and a Link switch to couple
its pitch to the Primary VCO.
● SUB OSC: additional oscillator with either a square or pulse wave output pitched   either
1 or 2 octaves below the primary oscillator.
● NOISE: Noise source with with either Pink and White output.
Filter
● Cascaded 4-Pole multimode (Lowpass; Highpass; Bandpass) OTA filter, switchable
between 2-pole and 4-pole.
● Special LP boost mode.
● Built in soft clipping.
● Allows for inverting ADSR mod source.
Modulators
● ADSR envelope with manual gate, and external level (velocity) control.
● Envelope has looping option, re-trigger, and selectable time range.
● Global modulation bus with four VCO waveforms, noise and S&H options.
Mixing and Output
● 27 jacks for creative and complex patching options — patch points for every synthesis
section.
● Mixer section includes an external source, which is normalled to a sinewave.
● Three position output clipping circuit.
● Output VCA has two stage clipping circuit.
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Atlantis Manual
Installation
Intellijel Eurorack modules are designed to be used with a Eurorack-compatible case and
power supply.
Before Your Start
Before installing a new module in your case you must ensure your case’s power supply has
sufficient available capacity to power the module:
● Sum up the specified +12V current draw for all modules, including the new one. Do the
same for the -12 V and +5V current draw. The current draw will be specified in the
manufacturer's technical specifications for each module.
● Compare each of the sums to specifications for your case’s power supply.
● Only proceed with installation if none of the values exceeds the power supply’s
specifications. Otherwise you must remove modules to free up capacity or upgrade your
power supply.
You will also need to ensure you have enough free space (hp)  as well as free power
headers in your case to fit the new module.
You can use a tool like ModularGrid to assist in your planning. Failure to adequately power
your modules may result in damage to your modules or power supply. If you are unsure,
please contact us before proceeding.
Installing Your Module
When installing or removing a module from your case always turn off the power to the case
and disconnect the power cable. Failure to do so may result in serious injury or equipment
damage.
Ensure the 10-pin connector on the power cable is connected correctly to the module before
proceeding. The red stripe on the cable must line up with the -12V pins on the module’s
power connector. The pins are indicated with the label -12V, a white stripe next to the
connector, the words “red stripe”, or some combination of those indicators.
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Atlantis Manual
Most modules will come with the cable already connected but it is good to double check the
orientation. Be aware that some modules may have headers that serve other purposes so
ensure the cable is connected to the right one.
The other end of the cable, with a 16-pin connector, connects to the power bus board of
your Eurorack case. Ensure the red stripe on the cable lines up with the -12V pins on the
bus board. On Intellijel power supplies the pins are labelled with the label “-12V” and a thick
white stripe:
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Atlantis Manual
If you are using another manufacturer’s power supply, check their documentation for
instructions.
Once connected, the cabling between the module and power supply should resemble the
picture below:
Before reconnecting power and turning on your modular system, double check that the
ribbon cable is fully seated on both ends and that all the pins are correctly aligned. If the
pins are misaligned in any direction or the ribbon is backwards you can cause damage to
your module, power supply, or other modules.
After you have confirmed all the connections, you can reconnect the power cable and turn
on your modular system. You should immediately check that all your modules have powered
on and are functioning correctly. If you notice any anomalies, turn your system off right away
and check your cabling again for mistakes.
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Atlantis Manual
Getting Started
If your previous experiences with learning to use synthesizers involved stepping through
presets, then you’re in for a shock — and a treat! Atlantis has no presets. Like modules and
synths of yore, the parameters on Atlantis are meant to be tweaked, twiddled and performed
in real time. The sound it generates correlates directly with the settings on its front panel —
there is no such thing as patch memory. What you see is what you hear.
While this makes Atlantis infinitely rewarding to sound designers and synthesists, it can be
slightly daunting to new users, since at least a modicum of basic knowledge is required to
coerce it into making the sounds you hear in your head.
In this Getting   Started   section, you’ll jump right into making sound, while simultaneously
getting comfortable with Atlantis’ front panel and layout. From there you’ll learn a bit about
Atlantis’ architecture and some fundamentals of subtractive analog synthesis before delving
into the Reference   section, where you’ll find a more detailed discussion of Atlantis’ many
features and capabilities.
Quick Start
Make a sound
1. Connect the jack labelled OUT to your system’s audio output.
2. Set all sliders to their minimum (bottom) positions.
3. In the MIX section, set the leftmost slider (PULSE) to its maximum.
4. In the VCO section, make sure SYNC is off (switch position at the bottom).
5. In the VCF section, set the FREQ slider to its maximum.
6. In the VCA section, set the ENV/GATE switch to the “GATE” position.
7. Push the GATE button (small red button beneath the ENV/GATE switch). You should
hear a sound that sustains for as long as you hold the button.
8. In the VCO section, rotate the OCTAVE and FINE knobs to tune the oscillator as you
like.
Audition the waveforms and filter types
1. In the MIX section, raise and lower all the sliders and make note of how the sound
changes as different waveforms are mixed together in varying amounts.
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Atlantis Manual
2. In the VCF section, set the top switch to “LP,” the POLES switch to “2,” and turn on LP
BOOST. Raise and lower the FREQ slider, and notice how the filter is removing high
frequency content.
3. In the VCF section, set the RES slider to its midpoint, then raise and lower the FREQ
slider. Notice how the filter’s cutoff frequency is now more pronounced.
4. While still in the VCF section, experiment with different settings of the LP/BP/HP switch
and the 2-POLE/4-POLE switch. Notice how these change what frequencies are being
filtered and how “steep” the filter sounds.
Modulate the filter
1. In the MIX section, set the leftmost slider (PULSE) to its maximum, and set all the other
MIX section sliders to their minimum.
2. In the VCF section, set the filter type to  “LP,” the POLES switch to “4” and set all the
sliders to the bottom, except FREQ, which you should set at the midpoint.
3. In the MOD section, set the VCO/LFO switch to “LFO;” set the RATE fader to the
midway point, and use the TYPE knob to select a triangle wave.
4. Back in the VCF section, raise the MOD slider to its midpoint. Notice that the filter’s
cutoff frequency is now being modulated by the MOD oscillator.
5. Back in the MOD section, raise and lower the RATE slider to change the rate at which
the LFO modulates the filter’s cutoff frequency. When finished, go to the VCF section
and reduce the MOD slider back to minimum.
Add an envelope
1. In the ENVELOPE section, set the CYCLE switch to its OFF position, and the x1/x10
switch to the “x1” position. Set the A (attack) and S (sustain) sliders to the bottom, and
the D (decay) and R (rate) sliders to the top.
2. In the VCA section, set the ENV/GATE switch to “ENV.”
3. Push the red button beneath the ENV/GATE switch and notice how the sound no longer
sustains indefinitely, but decays over time.
4. In the VCF section, set the filter type to “LP,” the POLES switch to “2” and set all the
sliders to the bottom, except FREQ, which should be about one-third of the way up.
5. Set the ENV POLARITY switch to the right (normal polarity) and press the red button in
the VCA section. You are probably hearing a fairly dark, quiet sound. If you don’t hear
anything, try increasing the FREQ slider until you just barely hear some signal passing
through the filter.
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Atlantis Manual
6. In the VCF section, slowly increase the ENV slider as you continue to press the little red
trigger button. Notice that the envelope shape is now being applied to the filter —
making it sound brighter at the beginning, then duller as the sound decays.
Try a little FM
1. In the MOD section, turn on LINK mode (switch position is up), set the VCO/LFO switch
to “VCO” and set the RATE slider to its midpoint.
2. In the VCO section, set the EXP/LIN switch to the “LIN” position, and slowly raise the
MOD slider to its midpoint while continuing to press the little red GATE button.
Experiment with different MOD levels in the VCO section and with different RATE levels
in the MOD section and notice the range of tonal variance that’s possible.
Use a sequencer (or CV keyboard)
1. Connect the gate output of your sequencer or CV keyboard to the GATE input at the top
of Atlantis.
2. Connect the pitch output of your sequencer or CV keyboard to leftmost 1V/OCT input at
the top of Atlantis.
3. Run the sequencer (or play the keyboard), and you should hear Atlantis playing the
melody.
4. In the VCA section, tune Atlantis by rotating the OCTAVE knob to set the desired pitch
range, and rotate the FINE knob to fine tune the pitch.
Now that you’ve explored some very rudimentary sounds, it’s time to dig into some analog
synthesis basics and learn a bit about Atlantis’ basic voice architecture.
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Atlantis Manual
Basic Architecture
Atlantis is comprised of several synthesis modules — wired in a normalled configuration,
with patch points for overriding the default connections (or for integrating with other modular
gear). The basic architecture looks as follows:
Using the same color-coding, the following illustration shows the location of these modules
(and their corresponding patch points) on Atlantis’ front panel:
An introduction to each of these modules appears in the sections below. See Panel Reference
for a detailed discussion of each module, knob, switch, slider, and jack.
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Atlantis Manual
VCO Overview
The VCO generates several different types of waveforms, including pulse, triangle and sine.
All waveforms are simultaneously accessible, and you can mix them together in varying
amounts using Atlantis’ MIX section (described below). The pitch of the VCO is set using its
OCTAVE and FINE knobs. The VCO will track an input source (such as a keyboard or
sequencer) plugged into Atlantis’ 1V/OCT jack, allowing for melodies.
Additional controls such as pulse width modulation (PWM); frequency modulation (FM); and
oscillator SYNC all alter the harmonic character allowing you to create richer, more
harmonically complex waveforms.
MIX Overview
The various waveshapes generated by the VCO are fed into the MIX section, where you can
blend them together in varying amounts. Different waveforms have different sonic
characteristics, so combining them in different ways results in a wide variety of timbres. For
example, sine waves are pure and void of harmonic content; square waves contain odd
numbered harmonics, making them sound richer and slightly “hollow;” sawtooth waves are
bright and brassy since they contain both even and odd harmonics.
This section adds two additional audio sources, which you can also blend into to the mix:
NOISE and a SUB OSCILLATOR. There is an additional input for bringing external audio
into the mix (which, when done, replaces the sine wave output from the VCO).
VCF Overview
The output of the MIX section feeds the Voltage Controlled Filter (VCF), which subtracts
certain frequencies and harmonics. This type of synthesis, in which you generate a richly
harmonic waveform and then remove certain frequencies with a filter, is called “subtractive
synthesis.”
Atlantis uses a 4-stage cascaded OTA filter similar to the type Roland used in the SH-101,
Jupiter-8, Juno-60 and other classic synths. In general, OTA filters produce less internal
distortion than Moog-style ladder filters, and are somewhat “smoother” sounding (though
with Atlantis’ built-in boost and drive options, there’s plenty of opportunity to rough up that
sound). In general, you can select between one of three types of filters: Lowpass (LP);
Bandpass (BP); and Highpass (HP). LP filters allow low frequencies to pass through the
filter, meaning that higher frequencies are removed, which results is a deeper sound; HP
filters allow high frequencies to pass through the filter, meaning that low frequencies are
removed. BP filters allow only a certain band of frequencies to pass through the filter,
removing frequencies that are both above and below the desired frequency.
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Atlantis Manual
The FREQ slider sets the frequency at which the filter activates. For example, if you
selected the LP filter and set the slider at maximum frequency, you would hear no effect.
That’s because you’ve told Atlantis that you want to pass all frequencies below this value —
and since you set the value is at the top of the audio range, you hear everything. By
gradually reducing the FREQ slider (in LP mode), you remove more and more high
frequency content until, at the bottom, you remove all audio content.
The filter can operate in either 2-pole or 4-pole mode. The number of poles a filter has
determines how aggressively the filtered frequencies are attenuated. A 2-pole filter reduces
frequencies by 12 dB per octave. So if you used the FREQ slider to cut all frequencies
above middle C (C3), then you would still hear frequencies corresponding to C4 — but they
would be attenuated by 12 dB. A 4-pole filter reduces frequencies by 24 dB per octave. So
in this case, if you set the filter to cut all frequencies above C3, then the frequencies
corresponding to C4 would be 24 dB quieter.
In addition to setting the FREQ at which you want signals to attenuate, you may also set a
RES (resonance) level. High resonance values accentuate the cutoff frequency, and the
higher the resonance, the more the filter seems to ring (or resonate) at that frequency. When
RES is set to maximum, Atlantis’ filter will self-oscillate — which means it resonates so
much that it becomes a sine wave oscillator whose pitch corresponds to the FREQ setting,
and which tracks an external keyboard or sequencer plugged into the filter’s 1V/Oct jack.
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Atlantis Manual
VCA Overview
After exiting the filter, audio passes through the VCA (voltage controlled amplifier) where its
volume level is shaped by the ENVELOPE (discussed below) when the ENV/GATE switch is
set to ENV. When that switch is set to GATE, then the VCA operates more like an organ —
switching the sound on to full volume when a signal appears at the GATE jack atop the
module, or when you press the little red button beneath the GATE switch. In GATE mode
the sound stays at maximum volume until the Gate signal is removed (or the button is
released). Additionally, there is a 3-position DRIVE circuit built into the VCA, which can
saturate Atlantis’ output, giving it a grittier, more aggressive sound.
ENVELOPE Overview
Sounds are rarely static. For example, a plucked string sound is brighter and louder at the
beginning, then grows duller and quieter over time. A bowed string takes longer to reach its
maximum volume (and brightness) as the bow digs deeper into the string.
To synthesize these time-based changes, Atlantis contains an ENVELOPE, which lets you
set the sound’s Attack time, Decay time, Sustain level and Release time. Using the ADSR
sliders, you can create many different contours. For example, you would create a short,
snappy sound by using a fast A, short D, no S, and short R. Or you can create a more
languid contour that slowly fades in (slow A), stays at maximum volume (full S), then fades
away slowly when you stop playing the note (long R).
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Atlantis Manual
In order to maximize the envelope’s usability, Atlantis gives you two ADSR scalings: x1 and
x10. Use the x1 setting when you need to create shorter, snappier envelopes with great
precision. Use the x10 setting to create longer, more lethargic envelopes.
Without needing to employ patch cables, Atlantis lets you route the envelope to numerous
destinations, including the VCA (volume contour of a note); VCO (pulse width contour of a
note); and VCF (timbral contour of a note). Additionally, Atlantis gives you the option of
inverting the envelope when sending it to the VCF. You can, of course, use Atlantis’ patch
points to route the envelope to any number of other internal (or external) destinations.
MOD Overview
The MOD section is a fully featured second VCO, and you can access its various
waveshapes using patch cables. In Atlantis’ default configuration, this oscillator serves as a
modulator — which means it’s used to dynamically alter (“modulate”) one or more other
parameters. The MOD oscillator operates at either audio rates or as a low frequency
oscillator (LFO), depending on the position of the VCO/LFO switch. Numerous modulation
shapes are available, including Sample & Hold (S&H) and noise.
Atlantis’ normalized architecture supports direct modulation of several parameters, including:
the frequency of the main VCO (FM); the pulse width (PWM) of both the main VCO and the
SUB OSC; and the VCF FREQ. More modulation options become available when the patch
points are used.
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Atlantis Manual
Panel Reference
This section discusses, section-by-section, every element on Atlantis’ front panel.
VCO
Controls
1. OCTAVE Select Knob
This 6-position knob sets the coarse tuning of the oscillator. Each position shifts the
tuning by one octave. Fine adjustment can be made using the FINE knob.
2. FINE Tune Knob
This knob finely adjusts the tuning frequency. The range is approximately +/- 6
semitones from the centre position.
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Atlantis Manual
3. PULSE WIDTH Slider
Sets the pulse width of the oscillator’s PULSE output. Different pulse widths produce
different timbres. With the slider at the bottom, the output produces a narrow 10%
duty cycle. With the slider at the top, the resulting pulse has a 90% duty cycle. A
square wave is produced with the slider exactly half-way up.
4. PWM Amount Slider
You can modulate the PULSE WIDTH over time using the PWM (pulse width
modulation) slider. This gives the waveform a sense of “movement.” Use the
corresponding PWM SOURCE switch to select a modulation source.
5. PWM SOURCE Switch
Selects a Pulse Width Modulation source. There are three options:
MOD: When switched to the top position, the output of Atlantis’ MOD oscillator varies
the pulse width over time. The input from the MOD oscillator is summed with the
PULSE WIDTH slider and, together, they set the width of the PULSE output.
EXT: When switched to the middle position, Atlantis uses a signal patched into the
PWM Input to vary the pulse width. The PWM input is summed with the PULSE
WIDTH slider and, together, they set the width of the PULSE output.
ENV: When switched to the bottom position, Atlantis uses the ENVELOPE to vary
the pulse width over time. The input from the ENVELOPE is summed with the
PULSE WIDTH slider and, together, they set the width of the PULSE output.
6. SYNC Switch
Switches the primary VCO into HARD SYNC mode. This forces the frequency of the
VCO to become slaved to a second, master oscillator. Every time the master
oscillator restarts its wave cycle, it forces the slaved oscillator (the VCO) to restart its
cycle. Richly harmonic waveforms result from setting the master and slave oscillators
to different frequencies.
By default, Atlantis uses a square wave from the MOD oscillator as the master
oscillator. So, when VCO is set to SYNC mode, the VCO’s pitch is actually controlled
by the MOD oscillator. If desired, you can patch a different oscillator into the VCO
SYNC input jack and synchronize to that instead.
To achieve classic analog sync sounds, patch your keyboard into the MOD’s
1V/OCT jack and tune it using the MOD oscillator’s RATE and FINE control. To get
that classic “dive bombing” sync sound, patch the ENVELOPE output into the VCO’s
1V/OCT jack and adjust the envelope to taste. TIP:   For   a   more   subdued   “dive   bomb”,
route   the   envelope   through   an   external   attenuator,   such   as   an   Intellijel   Triatt   or
Quadratt   1U   before   sending   it   to   the   VCO’s   1V/OCT   input   jack.
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7. MOD Amount Slider
This sets the depth of the FM effect. When the slider is at the bottom, no frequency
modulation occurs. Maximum modulation occurs at the top.
8. EXP/LIN Switch
Switches between two types of frequency modulation: EXP[ONENTIAL] and
LIN[EAR]. Its effect is most clearly heard (and understood) when the VCO/LFO
switch in Atlantis’ MOD oscillator is set to VCO.
See the FM synthesis discussion to learn about these two types of frequency
modulations, including their sonic characteristics, fundamental differences and sound
design uses.
Inputs and Outputs
A. PULSE Wave Output
Pulse wave output from the VCO. The width of the pulse is controlled by a
combination of the PULSE WIDTH knob and PWM input. Although Atlantis routes the
VCO pulse wave to the MIX by default, this jack lets you tap into that output directly
— sending it to alternate destinations either within Atlantis or within a larger eurorack
system.
B. SAW Wave Output
Sawtooth wave output from the VCO. Although Atlantis routes the VCO SAW wave
to the MIX by default, this jack lets you tap into that output directly — sending it to
alternate destinations either within Atlantis or within a larger eurorack system.
C. SINE Wave Output
Sine wave output from the VCO. Atlantis routes the VCO SINE wave to the mixer’s
EXTERNAL INPUT by default. If you choose to send external audio into the Mixer
instead of the sine wave, this jack enables you to still access that SINE wave —
sending it to alternate destinations either within Atlantis or within a larger eurorack
system.
D. SUB Osc Output
SUB Osc output from the VCO. Although Atlantis routes the Sub Osc to the MIX by
default, this jack lets you tap into that output directly — sending it to alternate
destinations either within Atlantis or within a larger eurorack system.
E. 1V/OCT Input
This input controls the pitch of the VCO, and is typically fed from the Pitch CV output
of a standard 1V/Oct keyboard or sequencer.
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F. PWM Input
This input has a range of +/- 5 V, and is used to modulate the pulse width when the
PWM SOURCE switch is set to EXT. The input is summed with the PULSE WIDTH
slider and, together, they set the width of the PULSE output. Note that external PWM
allows for pulse widths that extend down to 0% and up to 100%. At these two
extremes, the PULSE output is silent, further increasing the timbral complexity
available.
G. MOD Input
Linear or exponential frequency modulation input. The behaviour is set by the
EXP/LIN switch. Patching into this input disables the the input from the MOD
oscillator.
H. SYNC Input
With the SYNC switch turned ON, the VCO slaves to the waveform received at this
input. With no signal connected, the VCO slaves to the MOD oscillator’s square
wave output.
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