flight of harmony Infernal Noise Machine User manual

flight of harmony

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Contents
I.N.M. Features 3
Specications 5
What is it? 8
Controls and Usage 9
INM-Exp 13
Tips 14
Calibration 15
VCA 15
VCO 16
Modulation 17
Waveshaping 18
Thanks 22

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I.N.M. Features
Important Note:
This is a noise device. Please mentally append “-ish” to all descriptions.
IMP Noise Core:
• Controls
o Frequency & Range Joysticks
 Coarse
 Fine
à Fine scaling adjustment, relative to Coarse, at maximum Width
 1/5 to 1/25
à Fine scaling adjustment, relative to Coarse, at minimum Width
 1/125 to 1/500
o Domain rotary switch
 Select frequency band of IMP noise core
 1-8, lowest to highest
o Tone
 Low-pass lter to remove harshness in higher domains
o Frequency
 Width
à Width of Frequency band affected
 Frequency CV input attenuator
o Range
 Range CV input attenuator
 Width
à Width of Range band affected
o Domain (frequency range groups)
 8 switch-selected
• Tone control
o Variable between low-pass and all-pass
 Adjustment also varies phase interaction
• Inputs
o CV, 0 to +5V
 Over- and under-voltage protection
 Frequency and Range CV (buffered)
 Coarse Frequency and Range (Joystick)
 Fine Frequency and Range (Joystick)
 Frequency and Range Width (no attenuator)
• Outputs
o CV, 0 to +5V
 Coarse Frequency and Range
à Joystick, buffered, non-breaking
 Fine Frequency and Range
à Joystick, buffered, non-breaking
o Signal, ±5V
 Noise out

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
±5V soft-clip limited
Voltage-Controlled Oscillator (VCO):
• Variable base frequency
o ~0.5Hz to ~140kHZ
o Temperature compensated
o 1V/oct tracking
o CV input:
• Frequency Modulation
o Selectable modulation source
 Noise Signal from Imp
 External signal
o Variable modulation depth
o External signal input
o Level control
• Inputs
o CV

±12V
 VCO frequency
o Ext
 External modulation source
 AC-coupled

±5V soft-clip limited
o Mod CV
 VCO Modulation Depth
• Outputs, ±5V
o Square
o Ramp
o Saw
o Triangle
o Sine
Dual Voltage-Controlled Filter (VCF), one per channel:
• Controls
o CV
 Center Frequency CV input attenuator
o fc
 Center Frequency
o Gain
 Gain level
o Selector switches (In VCA section)
 In/Out
à Have VCF either In or Out of VCF -> VCA signal chain (bypass)
• Inputs
o fc CV
 VCF center frequency
 Buffered

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o Ext In
 External signal input
à AC-coupled
à Breaking
• Outputs
o Ext Out
 AC-coupled
 Breaking
Dual Voltage-Controlled Amplier (VCA), one per channel:
• Controls
o Level
o CV
 VCA output level CV input attenuator
• Inputs
o CV
 VCA level
 Buffered
o In
 External signal input
à Breaking
• Outputs
o Out
 Signal out
à ±5V soft-clip limited
à Non-breaking
o All Out
 Average of VCA1 & VCA2
à ±5V soft-clip limited
 Control
à Volume
Specications
• Type
o Paraphonic sound source/Oscillator
o CV & Signal processor
• Format
o Eurorack
• Width
o 48hp / 243mm / 9.6”
• Depth below panel
o 41mm / 1.625”
• Height above panel
o 28mm / 1.25”
• Power
o Current draw

+12V: 165mA (nominal)

-12V: -130mA (nominal)

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o 16-pin (2x8) Doepfer standard eurorack shrouded header
o User-selectable +5V supply
 System bus
 Onboard regulated supply
• Included
o Module
o 9” 16-pin to 10-pin & 16-pin power cable
o (4) M3x1.5x6 mounting screws
o (4) nylon washers
Functional Features
• IMP noise core audio source, generated by the nonlinear het-
erodyning of a pair of oscillators. The IMP has eight frequency
regions (Domains) of operation, from semi-random sub-audio
impulses to above audio range, used as the primary frequency
modulation (FM) source for the VCO. The output is also avail-
able to each signal chain as well as an independent output jack.
Frequency of oscillation is controlled by Coarse and Fine joysticks with
multiple Control Voltage (CV) inputs and other controls. The joysticks
have breaking input jacks for controlling external signals, and non-
breaking output jacks to allow the signal to be used externally as well
as control the IMP.
• Voltage-Controlled Oscillator (VCO) with Square, Ramp, Saw, Trian-
gle, and Sine, waveforms available to each signal chain along with
independent output jacks for each waveform. The VCO has two user-
selectable ranges:
1 Volt per Octave (1V/Oct) covering ~19Hz to ~44kHz.
Low-Frequency Oscillator (LFO) covering ~750Hz down to
~0.0015Hz (~11 minutes per cycle).
The VCO can be modulated by the internal IMP noise core or by
external modulation sources, and the modulation amount (depth) of either
can be controlled by dial and CV.
• 2 Audio signal chains consisting of a Voltage-Controlled Filter (VCF)
(bypassable) and a Voltage-controlled Amplier (VCA), each with
breaking inputs and outputs (I/O). These I/O allow the VCF and VCA
to be used independently or as inserts to the signal chain to allow
external effects to be added. The two VCA outputs can also be used to
provide stereo imaging and effects.
The VCF are Voltage-Controlled Filters. Filter band width and Gain are

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varied by the Gain control and the lter’s Center Frequency is varied by the
fc control and can also be voltage-controlled.
• The VCF In/Out bypass switches remove the lters from the signal
chain to pass the raw modulated VCO signal to the VCA.
• The VCAs have ±5V “soft-knee” output limiting protection for external
modules. Instead of hard clipping, which squares-off the peaks of the
signal, the soft-knee performs a gradual limiting of the signal as it ap-
proaches ±5V.
• Summed output of VCA 1 & VCA 2 available at the All Out jack, via
the Volume control.
Design Features
• Lifetime warranty against defects in assembly
• Components on one side of PCB for easier serviceability
• Modular build to allow simpler repair or replacement of hardware
• All trimming potentiometers accessible without disassembly
• Pin-to-signal identication on PCB silkscreen to aid servicing
• No electrolytic capacitors in signal path or power circuitry
Now that we have gotten this far, please, continue on and RTFM.

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What is it?
The Infernal Noise Machine is a sound synthesizer, not a music
synthesizer.
It was designed towards the creation of noise, sound effects, and for
the general eld of sound design. Having said that, the INM can create
a full range of “musical” tones and sound, but that was not the primary
goal. It can be used completely independently, but is intended for use
with external control voltage (CV) sources to affect or modulate various
parameters, which is where the INM truly comes alive.
So what can you do with it? Incidental sounds and ambiances, unholy
caterwauling, soundscapes from melancholy to manic, even percussion
and traditional musical sounds. The Infernal Noise Machine is particularly
effective for making drones that evolve with time, with no external sources
required. The internal architecture allows for a wide range of self-evolving,
beat-frequency style tonal variations over an innite range of rates. There
is really no simple way to describe what the INM can do – you have to
nd out for yourself. This is a unique device. It requires a bit of time and
patience to get a feel for how it works, but it is worth the effort.
The INM does not operate the same way as a traditional synth. The
traditional signal path in a synthesizer can be generalized as the following:
oscillator lter/effects/mixing output
The oscillator is the “heart”, so to speak, and everything else comes
further down the line. External modulation sources are used to vary different
aspects of the components of the chain, e.g.: oscillator frequency, lter
cutoff frequency and resonance, output level, and so on.
With the INM, the signal path is a bit different:
ToneTone
INM IMP
LPF
Noise
generator
Mod
depth
VCO
CV
Ext
In
VCO
Tune
level
level
Mod
CV
Alt
In
Alt
Out
level
Range
Width
Frequency
Domain
VCO
FM
LFO
FM
VCA
EXP
Alt
In
Alt
Out
All
Out
VCF
IN
OUT
Alt
In
Alt
Out
VCA
Alt
In
Alt
Out
VCF
IN
OUT
x
g. 1, Signal Flow Diagram
The voltage-controlled oscillator (VCO) is not the heart, but an effect.
The heart of the INM is the Imp , a voltage-controlled noise source. The

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VCO is used to “color” the tone of the noise. While the actual signal path
is technically the same as traditional synths, with the Imp being used to
modulate the frequency of the VCO, the key to proper use of the INM is
that the Imp is the core, and the VCO is an effect. The control panel is
specically laid out to enforce this relationship (gure 2).
Filter IMP
VCO OUT
Filter bypass VCA
g. 2, INM-E Panel
You know that part where a manufacturer says their product is new,
unique, like nothing you’ve seen before? This is basically that again, but
also a clarication that the Infernal Noise Machine does not work like most
sound source modules. To be even more clear:
This thing will piss you off.
It was designed to do new things in new ways, so there is a learning
curve. With both the original desktop INM and testers of the INM-E module,
some dove in and immediately understood how to use it, while others had
weeks of frustration, wondering why they kept getting variations of the same
ear-splitting drone (It got its name for a reason). Your prior experience with
synths doesn’t matter, either. We are even still nding new things that can
be done with it. Once it does click with you, however, you’ll understand
why we are so excited about bringing the INM-E to you.
Controls and Usage
Here is a brief explanation of the controls and their usage, described in
the same order as the signal path (see gure 1).
IMP
Domain, Frequency, Range and Width: Technically, all four describe the
same Function: what frequency the Imp puts out. The total possible range of

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the Imp, however, is from subsonic to ultrasonic, and accessed in different
ways requiring multiple controls for ne-tuning.
Domain: The rst stage of frequency selection. Domain selects one of
eight wide bands of the overall range. Domain One is lowest, Eight is
highest (in frequency). One is audible popping, Eight is nearly ultrasonic.
The Domains 7-8 are where you will nd the oddest/most ethereal Noises:
static, wind, the impression of voices. It has a lot of what seem to be dead
spots, but it is worth the time to wander the Domain and see what can be
found.
Frequency: This is the main frequency control within the selected Domain
- it sweeps over the entire Domain (depending on Range, see following).
The Fine control sweeps up to 1/5 of the size of the band that Coarse does.
Range: This controls how wide of a sweep Frequency covers. Fine
control same as with Frequency.
Width: Width makes the Fine into Extra Fine. In Domain 1, wide open
is best. In Domain 8 the bands of sound are very narrow, so it is best to set
the width all the way down to nd the hidden sweet spots.
•
2
1 2 3 4 5 6 7 81 2 3 4 5 6 7 8
Domain
Frequency
Range Width
(Fine joystick only)
Range
g. 3, Domain vs. Range vs. Width.
In other words, 1/8th of the possible frequency range is selected
by Domain, and the other controls select how much of that Domain the
frequency control can sweep across. The Coarse joystick is for a broad
sweep over the Domain, the Fine joystick is for nding the perfect “sweet
spot”, and Width is for when Fine isn’t Fine enough.
CV Level: The CV inputs have attenuators to adjust the level of external
signals. Fully clockwise is the actual CV level, fully counter-clockwise is full
attenuation.
Tone: The Noise generator has two output ampliers - a buffer and a
low-pass lter (LPF), the Tone knob controls the mix/cross fade between
these two outputs. The phase relationship between these outputs varies
depending on the Noise frequency; sometimes in phase, sometimes 90°,

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sometimes 180°, and everything in between.
VCO
CV Level: Controls the attenuation of the external CV signal.
VCO Tune: Tuning control to adjust the frequency of the VCO.
Mod Src: Selects which signal is used to modulate the frequency of the
VCO. Int selects the Imp, Ext selects the Ext In input. The switch should be to
the Int position when no external source is connected.
Ext Level: Controls the attenuation of the Ext In signal.
Mod Depth: Controls how “deeply” the selected frequency modulation
(FM) source affects the VCO. Turn fully clockwise for maximum modulation,
fully counter-clockwise for zero modulation.
Main Filter Section:
After the VCO, the signal is routed the lter section, where it is split into
two paths to feed into the two VCF.
Input: These switches select one of the available waveforms to send
to the lter. The rst ve are supplied by the VCO - Square, Ramp, Saw,
Triangle, and Sine, while the sixth connects the lter input directly to the
output of the IMP – think of it as a VCO bypass.
Filter Bypass
Here we take a quick jump up by the VCA section, to the Bypass VCF1
and Bypass VCF2 switches. These two switches allow you to bypass the
voltage-controlled lters (VCF) and send the selected signal (selected with
the Input rotary switches) directly to its voltage-controlled amplier (VCA)
with no ltering. Now back to the lters:
Gain: Controls the gain of the lter. Fully counter-clockwise is (almost)
full attenuation, fully clockwise is maximum gain. The gain is similar to
“depth”, but also greatly varies the lter character. Actual quantitative gain
is dependent on the input frequency, so it’s all over the place.
fc1 & fc2: These should be read as: “center frequency of lter 1 &
center frequency of lter 2”. These controls are used to change the fcof the
lter, changing what frequency band is emphasized and the overall tone
of the signal.
CV Level: Controls the attenuation of the external CV signal. For the
VCBPF, the CV varies the center frequency.

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VCA section
This is the output section. Each of the two signals is sent to a VCA, and
the outputs of the two VCA are summed together and sent to the All Out
jack.
Level: The level control for the VCA. Fully clockwise is maximum (±5V),
and fully counter-clockwise is full attenuation.
CV Level: Controls the attenuation of the external CV signal, used here
to vary the level of the output signal.
Volume control
This is the last stop for the signal on its way to the All Out jack, the
volume control. Turn clockwise for full volume, counter-clockwise for full
attenuation.

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INM-Exp
The INM-Exp is an additional set of ve waveform
outputs and three frequency controls for the Infernal Noise
Machine.
The toggle switch selects how it is controlled: When set
to Exp, the LFO output is controlled only by the expansion
module and is isolated from the main unit, overriding and
ignoring the CV+Mod source from the main INM-E. Tune
controls the frequency, just as the one on the main INM-E,
and CV is the level control for the CV input jack.
When set to INM, the LFO tracks the CV + Mod
signal in the main INM-E as per usual and the INM-Exp
knobs and CV jack are disconnected from the system;
they do nothing. The LFO works as normal, but with the
LFO waveforms additionally available from the INM-Exp
jacks. This means the LFO tracks the 1V/octave VCO to
some degree, but the LFO is not 1V/oct, so don’t expect
awless tracking.
In specic:
With INM-E VCO toggle set to 1V/oct and INM-Exp set to Exp:
• INM-E VCO outputs are 1V/oct rate, tracking CV +Mod
source as explained in original description.
• INM-Exp outputs are LFO rate, tracking the INM-Exp Tune +
CV jack, no modulation from the main INM.
With INM-E VCO toggle set to 1V/oct and INM-Exp set to INM:
• INM-E VCO outputs are 1V/oct rate, tracking CV +Mod
source as explained in original description.
• INM-Exp outputs are LFO rate, tracking CV +Mod source
as explained in original description, INM-Exp knobs and
CV input are disabled.
With INM-E VCO toggle set to LFO and INM-Exp set to Exp:
• INM-E VCO outputs are LFO rate, tracking the INM-Exp Tune + CV jack, no
modulation.
• INM-Exp outputs are LFO rate, tracking the Exp Tune + CV jack, no modulation
from the main INM.
With INM-E VCO toggle set to LFO and INM-Exp set to INM:
• INM-E VCO outputs are LFO rate, tracking CV +Mod source as explained in
original description.
• INM-Exp outputs are LFO rate, tracking CV +Mod source as explained in
original description.
g. 18, INM-EXP LFO
Expansion module

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Tips
• Take your time. It is easy to get frustrated with the INM. I nd the best
stuff when I am just noodling around while testing (and end up taking
an hour to test one unit because I got lost in the drones or something).
I tend to have a harder time when I go in trying to make a cool sound.
The INM is built on subtleties and small changes making big differ-
ences.
• When modulating the VCO, the greater effect is when the VCO and
the Noise frequencies are closer together, i.e., the effect is minimal
when the VCO is in the bass range and the Noise Domain is in Eight,
but extremely dominant when similar in frequency.
• Saw on one channel + Ramp on the other channel = nothing. They
cancel almost completely.

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Calibration
Note: Scope display settings are how I do them and are provided for those
with little experience. Do it however you want if you are familiar with the
equipment
VCA
g. 4, VCA calibraon trimmer potenometers.
Tools required:
• Oscilloscope
• Small at-bladed screwdriver
Setup:
• Oscilloscope:
o Set display to 2.5 Volts per division
o Connect oscilloscope to VCA Out jack.
• Set related VCF bypass toggle to Out.
• Set Channel VCO waveform switch to Square.
• Set VCA Level to maximum (full CW1).
Procedure:
Observe waveform on oscilloscope display. Adjust to ±5V centered on 0
Volts (g. 5). AMP adjusts amplitude of output, BIAS adjusts baseline shift
from zero. Repeat for second channel.
g. 5, VCA calibraon oscilloscope display.
1. CW = ClockWise, CCW = Counter-ClockWise

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VCO
1 Volt Per Octave
Note: This is the Infernal Noise Machine, don’t ask about tracking or how
many octaves, k? If you want a precision VCO with perfect tracking across
eighty octaves, you’re in the wrong place.
Tools required:
• Small at-bladed screwdriver
• Frequency meter
• Voltmeter
Reference points:
g. 6, CV and Common on rear of VCO PCB.
g. 7, Side of INM-E showing V/Oct and BaseF trimmers, and alternate Common
reference point.
Procedure:
• Power up your INM-E and allow it to warm up for about 30 minutes.
• Adjust VCO panel controls:
o Set Tune to midway.
o Set CV to minimum (full CCW)
o Set Mod Depth to minimum (full CCW)

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o Set Ext to minimum (full CCW)
o Set VCO toggle to 1V/Oct
Calibration
• Adjust the Tune knob until voltage at the pin marked “CV” in g. 7 reads
0.00V.
• Adjust the BaseF trimmer (g. 7) until frequency counter reads 800.0 Hz
• Apply 5.00VDC to VCO In 1V/Oct CV input. Turn CV level knob full CW.
• Adjust V/Oct trimmer (g. 7) until output is 28.16 kHz
• Repeat the above three steps several times (usually 2-3 more times) until outputs
are stable.
Modulation
Modulation of the VCA, both internal and external sources, is done with
a dedicated modulation amplier. The standard calibration is as follows.
g. 8, VCO Modulaon trimmer potenometers and TP1 test point.
Tools required:
• Function generator
• 2-channel oscilloscope
• Small at-bladed screwdriver
Setup:
• Oscilloscope:
o Set display to 1V per division
o Set vertical mode to chop (display both channels simultaneously)
o Verify both channels set to same 0V baseline.
o Connect channel 2 to test point TP1.
• Function generator:
o Set to ±2V, 1kHz triangle output.
o Connect output to oscilloscope channel 1 and to VCO In Ext of INM,
• INM:
o Set Mod Src toggle to Ext.
o Turn Ext Level to maximum CW.
Procedure:
• Observe waveform on oscilloscope display. Adjust until channel 2 waveform is
identical to channel 1 (g. 9). MODAMP adjusts amplitude of output, MODBIAS
adjusts baseline shift from zero.

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g. 9, VCO modulaon amplier calibraon oscilloscope display.
Waveshaping
VCO
Note: The VCO is a fairly standard ramp oscillator, with the Triangle
created from manipulation of the ramp, which leaves some artifacts. The
Sine is derived by distortion of the Triangle, so it contains some of these
artifacts as well.
g. 10, VCO waveshaping trimmer potenometers
Tools required:
• Oscilloscope
• Small screwdriver
Setup:
• Oscilloscope:
o Set display to 2.5 Volts per division
• Set VCO toggle to VCO
• Set Mod Depth to minimum (CCW)
• Set Tune to midway.
Procedure:
Use the VCO Out jacks to calibrate each waveform in turn.
• Square
o Nothing to change here, please move along.
• Ramp - RMPBIAS
o Adjust RMPBIAS (g. 10) until signal is vertically centered on 0 Volts (g. 11)

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g. 11, Ramp Bias adjustment display.
• Saw —RMPBIAS
o Saw is just an inverted ramp, you’ve done enough already.
 No, really, ignore any offset variance, it’s ne.
• Triangle —TRIBIAS, TRSIADJ
o TRIBIAS is identical in function to RMPBIAS. Adjust to correct waveform offset.
o TRSIADJ controls the conversion of the ramp into a triangle, adjust this until
the display shows an equilateral triangle-ish shape (g. 12).
 No, I’m not getting bored with writing this manual at all.
g. 12, Eect of adjusng the TRSIADJ trimmer potenometer
• Sine — TRSIADJ, SINAMP, SINRND, SINBIAS
o Ready for fun? The sine is derived by nonlinear distortion of the triangle and
has four trimpots that affect its shape. Sine is also the only one that has an
amplitude adjustment. Because I’m nice like that.
 I mean, really, the damn thing has enough trimpots already, doesn’t it?
o TRSIADJ affects both triangle and sine. Adjust to correct any unevenness at
the bottom of the waveform, but it will also affect the triangle. Find a suitable
medium.
o SINBIAS is not the same as the other bias adjustments — the uppy-downy
thing — it is the bias on the distortion applied to the triangle relative to the
zero Volt baseline. Adjust this until the top and bottom of the sine are
balanced (g. 13).
o Confession: the labels for SINAMP and SINRND are swapped. Ignore what
the words mean please. You have to adjust the two of them together anyway,
so it’s not that big of a deal. Following this:
 SINRND controls the amplitude (height) of the sine. Adjust this until the
sine is roughly ±5V
 SINAMP controls the roundness of the sine (g. 14). Adjust this next until
the shape resembles a sine wave.
 If, for some reason, you really borked2your sine wave or are just having
2. Really screwed up.

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fun screwing around, you may have to go back and forth between
SINRND and SINAMP to get the shape right.
 You’re not going to get a perfect sine wave, by the way. Noise Machine,
remember?
g. 13, SINBIAS trimmer potenometer adjustment.
g. 14, SINAMP trimmer potenometer adjustment.
LFO
Note: The LFO is a basic triangle oscillator, with all other waveforms derived
by distorting the original triangle and its attendant timing square wave.
g. 15, LFO trimmer potenometers.
Tools required:
• Oscilloscope
• Small screwdriver
Setup:
• Oscilloscope:
o Set display to 2.5 Volts per division
• Set VCO toggle to LFO
• Set Mod Depth to minimum (CCW)
• Set Tune to 3/4 CW to full CW.
 Enough to have several cycles visible in the display.