Loquelic Iteritas - Synthesizer Noise Engineering - Free user manual and instructions

Product Type	Eurorack Synthesizer Module
Brand	Noise Engineering
Model	Loquelic Iteritas
Category	Digital Oscillator
Format	Eurorack
Width	10 HP
Depth	25 mm (approx.)
Power Requirements	+12V: 100 mA, -12V: 20 mA
Power Connector	10-pin Eurorack ribbon cable
Main Functions	Three oscillator cores (Even, Odd, Mimetic) with morphing and modulation
Controls	Frequency, Mod, Morph, and CV attenuation knobs; toggle for core selection
CV Inputs	Pitch, Mod, Morph, and Sync
Audio Output	1x 3.5mm mono jack, 10Vpp
Sample Rate	48 kHz
Bit Depth	16-bit
Maintenance & Cleaning	Keep dry; clean with a soft, dry cloth. Avoid solvents.
Safety	Power off before connecting/disconnecting. Use only in dry environments.
Spare Parts & Repairability	Contact Noise Engineering or authorized distributors. Module should be serviced by qualified technicians.

Frequently Asked Questions - Loquelic Iteritas Noise Engineering

What is the power requirement for the Loquelic Iteritas?

The module requires +12V at 100 mA and -12V at 20 mA via a standard 10-pin Eurorack ribbon cable. Ensure your power supply can provide adequate current.

How do I calibrate the Loquelic Iteritas?

Calibration is not user-adjustable. The module is factory calibrated. If you experience pitch tracking issues, check your power supply and CV source.

What does the three cores (Even, Odd, Mimetic) do?

The core determines the waveform algorithm. Even produces symmetrical waveforms, Odd produces asymmetrical, and Mimetic creates complex evolving timbres. Switch between them using the toggle.

Can I use it as a standalone VCO?

Yes, it functions as a digital VCO. Patch the audio output to your mixer or VCA. Use the Pitch CV input to control frequency, and the Mod and Morph CVs to shape the sound.

How deep is the module? Will it fit in my case?

The depth is approximately 25 mm (excluding power cable). Most Eurorack cases accommodate this depth, but measure your case to be sure.

What is the purpose of the Sync input?

The Sync input resets the oscillator phase on each rising edge. Use it to synchronize the Loquelic Iteritas with other oscillators or clock sources for hard-sync effects.

Does it retain settings on power down?

No, the module does not have non-volatile memory. Upon power-up, it returns to default settings. CV controls the parameters dynamically.

What is the output level? Can I drive headphones directly?

The audio output is 10Vpp typical. This is line level and suitable for modular mixers. It is not recommended to drive headphones directly without an amplifier.

How do I clean the module?

Disconnect power and use a soft, dry cloth to wipe the front panel. Do not use liquids or abrasives. Keep jacks free of dust.

What forms of modulation are available?

The module accepts CV for Pitch (1V/oct), Mod, Morph, and Sync. The Mod and Morph CVs have attenuators. Additionally, the internal modulation can be self-patched.

USER MANUAL Loquelic Iteritas Noise Engineering

Complex Digital Oscillator

Overview

Type VCO
Size 10HP	Eurorack
Depth	1 Inch
Power 2x8	Eurorack
+12 mA	150 / 80
-12 mA	5
+5 mA	0 / 90 (optional)

"I could kill someone with that" -- DJ Surgeon

"This thing sounds fucking amazing lots of stuff I've never heard before" -- Surachai

Loquelic Iteritas is a digital VCO with interpretations of three classic synthesis algorithms involving dual pitch control. It creates a huge variety of sounds parameterized by four tone and two pitch controls.

Before Serial 555

After Serial 555

Noise Engineering Loquelic Iteritas

Complex Digital Oscillator

Patch Tutorial

The easiest way to get to know Loquelic Iteritas is to turn the knobs and listen. Connect the output to your mixer and start twiddling.

Loquelic Iteritas is about continuous tone control. Hook any LFO up to any of the four tone control inputs (Morph, Fold, Modulate, Damp).

Other interesting effects can be created by controlling the pitches independently (by default the 1v/8va inputs are normaled to each other). For instance, using a Tonnetz Sequent to produce musical intervals produces interesting results.

Noise Engineering

Loquelic Iteritas

Complex Digital Oscillator

Interface

Pitch A

The pitch of oscillator A can be controlled by the 1v/8va input and offset by its coarse and fine knobs. The pitch inputs are cross-normalized.

Pitch B

The pitch of oscillator B can be controlled by the 1v/8va input and offset by its coarse and fine knobs. The pitch inputs are cross-normalized.

Damp

is a tone control. Consult the following pages detailing each mode to find the behavior of this knob in the specific mode.

Mod

is a tone control. In all modes it controls phase modulation between the two pitch oscillators.

Fold

is a tone control. In all modes it controls the threshold of the wavefolding.

Morph

is a tone control. In all modes it controls the waveform of the oscillator continually varying between sine, triangle and saw.

Algorithm

selects which algorithm is used. These are detailed on the following pages.

Master

controls the sync of the oscillators. When in the middle position both oscillators are free running. When A is selected oscillator B will sync to oscillator A. when B is selected A will sync to B.

Sync

Sync will reset the state of the oscillators on a rising edge. Used for sync modulation. This jack was added starting at serial 700.

Out

Out is the AC coupled audio output.

Noise Engineering

Loquelic Iteritas

Complex Digital Oscillator

Calibration

Loquelic Iteritas is best calibrated using a stroboscope and tuning octaves across the pitch range. Each pitch input has as separate calibration. The pitches can be isolated from each other by using the master switch to force the base pitch to be determined by only one input.

Voltage Supply

Loquelic Iteritas can run it's processor on the 5V eurorack power rail to reduce noise and load on the 12V bus. There are three different versions of the CPU board two which use a switch to select and one which uses a jumper. For the swtich versions gently push the switch tab in the direction of the desired rail to use. For the jumper version put the jumper from the center pin to the pin marked with the rail that is deesired.

Noise Engineering Loquelic Iteritas

Complex Digital Oscillator

Algorithm: V0

The V0 algorithm is roughly based on the VOSIM algorithm, which I discovered while reading Curtis Roads's epic Microsounds. This algorithm amplitude modulates a carrier by an exponential to create a more complex harmonic structure. The simplest carrier is a sinusoid, which produces a spectrum with a Gaussian distribution centered on the carrier. More complicated waveforms produce Gaussians around each harmonic, resulting in spectra similar to comb-filtered noise.

Pitch A is the fundamental frequency of the carrier. Pitch B is the retrigger frequency of the exponential decay.

Interface

MORPH - changes the waveform of oscillator A

DAMP - sets the decay constant on oscillator B relative to its period

MOD - phase modulates oscillator A by oscillator B

FOLD - sets the wave fold threshold on the final wave folder

References

Kaegi, Werner, and Stan Tempelaars. "Vosim-a new sound synthesis system." Journal of the Audio Engineering Society 26.6 (1978): 418-425.

Roads, Curtis. Microsound. MIT press, 2004.

Loquelic Iteritas Mode: UO

Noise Engineering Loquelic Iteritas

Complex Digital Oscillator

Algorithm: SS

Algorithm SS is a highly modified version of summation synthesis originally developed by James Moorer. The premise comes from a simple mathematical equality between an infinite harmonic series and a relatively easy to compute expression.

Original equation:

() - a ( - β)1 + a ^ 2 - 2 a (β) = _ x = 0 ^ ∞ (θa ^ x β) + x

This equation allows a wide variety of musical spectra to be produced by only two parameters. Loquelic Iteritas generalizes the sinusoidal terms into multi-waveform oscillators: two of these track the two input pitches while the third tracks the difference of the two pitches and adds a wave folder for more harmonics. In the equation oscillator A is the left sinusoidal term in the numerator. Oscillator B is the sinusoidal term in the denominator.

Modified Equation:

(w _ A t) - a _ B (wt - wt)1 + a ^ 2 - 2 a (wt) = _ x = 0 ^ ∞ wa ^ x t w _ A (t) x _ B

Interface

MORPH - changes the waveform of all oscillators

DAMP - sets the a parameter in the equality. This controls the generated spectra with higher values producing higher power harmonics.

MOD - phase modulates oscillator A by oscillator B

FOLD - sets the wave-fold threshold on the final wave folder

References

Moorer, James A. "The synthesis of complex audio spectra by means of discrete summation formulas." Journal of the Audio Engineering Society 24.9 (1976): 717-727.

Jolley, Leonard Benjamin William, ed. Summation of series. Courier Corporation, 2012.

Loquelic Iteritas Mode: SS

Noise Engineering Loquelic Iteritas

Complex Digital Oscillator

Algorithm: PM

The PM algorithm is a naive time-domain two-oscillator phase-modulation implementation that combines both oscillators with amplitude modulation.

Interface

MORPH - changes the waveform of both oscillators

DAMP - blends between oscillator A and B through their product (AM)

MOD - phase modulates the oscillators by each other

FOLD - sets the wave-fold threshold on the final wave folder

Loquelic Iteritas

Mode: PM

Noise Engineering Loquelic Iteritas

Complex Digital Oscillator

Sample Rate

Loquelic Iteritas uses a unique multisampling technique to make aliasing more musical. By choosing a particular sample rate for a waveform that has a harmonic structure (all overtones are integer multiples of the fundamental), the alias power can be moved into frequencies that are also multiples of the fundamental and therefore more musical.

This gets complicated when synthesizing two oscillators at different pitches but using the same DAC. The compromise that Loquelic Iteritas makes is to give up the notion of a fixed sample rate and compute a time delay between samples based on both oscillators. For the single oscillator case, this delay is based entirely on pitch. If this delay is computed based on each oscillator's pitch, both sample rates can be interleaved by checking which oscillator's delay will be up first. This oscillator is then updated to its next timestep and an output value is computed based on both oscillator's output state. This makes no guarantees about exactly where the aliasing goes. It is an attempt to make the aliasing related in some way to the fundamental pitch.

Two independent sample rates combine to form one irregular sample rate. Sample rate is not a constant.

Noise Engineering Loquelic Iteritas

Complex Digital Oscillator

Design Notes

Loquelic Iteritas has been in development for over two years. It was started at the same time as Basimilus Iteritas but has taken much longer to mature. Originally it was just a simple implementation based on VOSIM but I soon realized I could pack a lot more punch in this form factor and found two additional algorithms. Loquelic Iteritas was designed to be a functional oscillator for sound designers as well as for musicians. I wanted to maximize the possible sound space given the input controls going from simple calm sounds to extreme, even broken, sounds. The priority of tonal variance led to some sacrifices on the musical side such as the total pitch range.

The algorithms used are quite simple and are intentionally left naive as they often include interesting rough spots. For example, PM mode has a nasty half-sample-rate self oscillation under high modulation indexes that, when combined with the irregular sample rate, produces interesting, if quite harsh, results.

Noise Engineering Loquelic Iteritas

Complex Digital Oscillator

Code

For reference I have included the core synthesis code for each algorithm. I am constantly amazed at how much sound variety such simple algorithms can produce and hope that others will appreciate their simplistic beauty. Note: code superfluous to the core algorithm has been removed.

Noise Engineering

Loquelic Iteritas

Complex Digital Oscillator

Code: V0

unsigned LI_FrameVO()
{
    int delay;

    if((state.voOsc.delay - state.voR1) < (state.voEnv.delay - state.voR2))
    {
    if(state.voOsc.sync && state.current.syncSw == LI_SYNC_B)
    {
    NeAttackDecayReset(state.voEnv);
    }

    state.voOutC = NeMoscSample(state.voOsc, state.morph, state.voMod);
    delay = state.voOsc.delay - state.voR1;
    if(delay < 0) delay = 0;
    state.voR1 = 0;
    state.voR2 += delay;
    }
    else
    {
    state.voOutE = NeAttackDecayOscSample(state.voEnv);
    state.voMod = fix24_mul(state.voModAmt, 2 * (state.voOutE - FIX24_HALF));

    if(state.voEnv.reset && state.current.syncSw == LI_SYNC_A)
    {
    NeMoscReset(state.voOsc);
    }

    delay = state.voEnv.delay - state.voR2;
    if(delay < 0) delay = 0;
    state.voR2 = 0;
    state.voR1 += delay;
    }

    fix24 out = 0;
    out = NeFoldSample(state.fold, state.voOutC);
    out = fix24_mul(state.voOutE, out);
    out = fix24_mul(state.voMComp, out);
    out = fix24_soft_clip_poly(out);
    return fix24_to_u16_audio_delay(out, delay);
} 

Noise Engineering

Loquelic Iteritas

Complex Digital Oscillator

Code: DS

unsigned LI_FrameDS()
{
    fix24 out = 0;
    int delay = 0;

    state.dsPb = NextC( state.dsPc, state.dsPm, state.dsPb);

    int dc = state.dsOscC.delay - state.dsRc;
    int dm = state.dsOscM.delay - state.dsRm;
    int db = state.dsOscB.delay - state.dsRb;

    if(dc <= dm && dc <= db) //dc is next
    {
    fix24 phaseC = fix24_mul(state.dsOutM, state.dsMod);
    state.dsOutC = NeMoscSample(state.dsOscC, state.morph, phaseC);
    delay = dc;
    if(delay < 0) delay = 0;
    state.dsRc = -delay;
    }
    if(dm <= dc && dm <= db) //dm is next
    {
    fix24 phaseM = FIX24_QUARTER + state.morph;
    state.dsOutM = NeMoscSample(state.dsOscM, state.morph, phaseM);
    delay = dm;
    if(delay < 0) delay = 0;
    state.dsRm = -delay;
    }
    if(db <= dm && db <= dc) //db is next
    {
    state.dsOutB = NeMoscSample(state.dsOscB, state.morph);
    delay = db;
    if(delay < 0) delay = 0;
    state.dsRb = -delay;
    }

    if(state.current.syncSw == LI_SYNC_A)
    {
    if(state.dsOscM.sync) NeMoscReset(state.dsOscC);
    }
    else if(state.current.syncSw == LI_SYNC_B)
    {
    if(state.dsOscC.sync) NeMoscReset(state.dsOscM);
    }

    state.dsRc += delay;
    state.dsRm += delay;
    state.dsRb += delay;

    fix24 a = state.dsA;
    fix24 a2 = fix24_mul(a, a);
    fix24 n = state.dsOutC - fix24_mul(a, state.dsOutB);
    fix24 d = FIX24_128TH + FIX24_ONE + a2 - 2 * fix24_mul(a, state.dsOutM);
    out = fix24_mul(FIX24_3RD, fix24_div(n, d));
    out = fix24_mul(state.morphScale, out);
    out = fix24_soft_clip_poly(out);
    out = NeFoldSample(state.fold, out);
    return fix24_to_u16_audio_delay(out, 2 * delay);
} 

Noise Engineering

Loquelic Iteritas

Complex Digital Oscillator

Code: PM

unsigned LI_FramePM()
{
    fix24 out = 0;
    int delay = 0;

    int updateDelay1 = state.pmOsc1.delay - state.pmR1;
    int updateDelay2 = state.pmOsc2.delay - state.pmR2;

    if(updateDelay1 <= updateDelay2) //update whichever osc is due next
    {
    state.pmOut1 = NeMoscSample(state.pmOsc1, state.morph, state.pmPhase1);
    delay = updateDelay1;
    if(delay < 0) { delay = 0; }
    state.pmR1 = 0;
    state.pmR2 += delay;
    }
    else
    {
    state.pmOut2 = NeMoscSample(state.pmOsc2, state.morph, state.pmPhase2);
    delay = updateDelay2;
    if(delay < 0) { delay = 0; }
    state.pmR1 += delay;
    state.pmR2 = 0;
    }

    if(state.current.syncSw == LI_SYNC_A && state.pmOsc2.sync)
    {
    NeMoscReset(state.pmOsc1);
    }
    else if(state.current.syncSw == LI_SYNC_B && state.pmOsc1.sync)
    {
    NeMoscReset(state.pmOsc2);
    }

    state.pmPhase1 = (7 * state.pmPhase1 + fix24_mul(state.pmMod1, state.pmOut2)) >
    state.pmPhase2 = (7 * state.pmPhase2 + fix24_mul(state.pmMod2, state.pmOut1)) >

    fix24 am1 = fix24_mul(state.pmOut1, state.pmAM1);
    fix24 am2 = fix24_mul(state.pmOut2, state.pmAM2);
    fix24 am3 = fix24_mul(am1, am2);
    out = am1 + am2 + am3;
    out = fix24_soft_clip_poly(out);
    out = NeFoldSample(state.fold, out);
    return fix24_to_u16_audio_delay(out, delay);
} 

Noise Engineering

Loquelic Iteritas

Complex Digital Oscillator

Special Thanks

Kris Kaiser

Shawn Jimmerson

Cyrus Makarechian

William Mathewson

Mickey Bakas

Tyler Thompson

Alex Anderson