Humble Audio Quad Operator

MUSICAL FEATURES

XNUMX variable waveform operator banks for linear FM

Humble Audio Quad Operator is a quad-operator bank with four operators (oscillators) and a flexible and powerful modulation matrix, allowing for classic FM structures like DX presets, as well as continuously evolving textures, experimental feedback patches, and use as a complex modulator in LFO mode. There is no concept of a modulated carrier; it consists only of four operators that can be freely cross-modulated.

• Implemented from scratch, including firmware, Quad Operator offers a modern approach to FM synthesis
• One function per knob for ease of use
• Any FM algorithm is possible via the modulation matrix
• Algo Expander ModuleSave / recall algorithm (sold separately) and provide crossfade function
• Independent signal output for each operator
• Level control by VCA installed for each operator
• External audio rate FM input (with adjustable amount of modulation send to each operator individually)AR FMInput). It is possible to feed back the signal from the internal operator as well as the external audio rate signal.
• Each operator can also unlock and tune and patch individually. The module can also be a multifunctional oscillator bank.
• High-quality digital emulation of classical analog waveforms
• Equipped with LFO mode. Generate complex, phase-locked modulation signals
• Firmware update by user is possible

How to Use

Locked and free 

Each operator can be switched between Lock and Free states. In the Locked state, the frequency of an operator is controlled within a range that provides a perfect integer frequency ratio for both the Coarse and Fine parameters. This is crucial for generating waveforms with harmonious harmonics, and this state is suitable for classic FM sounds. The Detune control introduces subtle or extreme discordant effects that deviate significantly from this integer ratio relationship.

In the free state, each operator essentially functions as an independent oscillator. In this case, each operator's Ratio knob becomes a continuously variable knob for its own coarse tuning, and Ratio CV becomes a 1V/Oct control for each operator . If all modulation is set to zero, up to four independent oscillators can be used. Even in this state, modulation is still applied, but FM without frequency/phase locking tends to be dissonant.

External modulation function

The Quad Operator features an audio input circuit called AR FM input, which allows external signals to be input as modulators . Above the input jack are an LED indicating clipping and a knob for gain adjustment. The magnitude of the AR FM input signal can also be controlled by voltage via the AR FM gain CV input below it. The signal to the AR FM is first sent after the master gain is adjusted, and then the amount of modulation sent to each operator is further controlled by the four knobs at the bottom of the modulation matrix.

Algo Expander

The separately sold Algo Expander adds the ability to save and crossfade all operators and AR FM inputs, as well as the position of their respective " Mod x " knobs (modulation matrix parameter values). Conceptually, each slot can be thought of as corresponding to the algorithm of a classic FM synthesizer. There are three slots, A, B, and C, and a Live slot that represents the current modulation matrix knob position.

Starting point of the patch

It can be confusing the first time you play the Quad Operator, as playing around with a lot of parameters can easily lead to a noisy and harmonious sound. As a starting point, set the parameters with reference to the following to avoid chaotic results. By moving knobs and patches with this setting as the starting point, you can gradually approach dissonance and noise.

• VCO / LFO switchVCOTo set.
• All operatorsOn the rocks international success.
• allDetuneKnob12Set at the hour position. -ThisRatioIt guarantees an integer frequency relationship determined only by the knob.
• allShapeKnobCounterclockwiseSqueeze. -Start with a sine wave, like traditional FM. We recommend starting without modulation, as combining waveforms with harmonics and modulation can quickly cause aliasing and noise.
• allModulation sendTheCounterclockwiseSqueeze. -Multiple mods and cross / self mods can also cause aliasing and noise.

Interface

Calibration

It is important to calibrate the V/Oct and Ratio inputs (when free) so that they accurately interpret a 1-volt change. If your Quad Operator sounds like it is not tracking the pitch correctly with these inputs, please perform the calibration using the following steps.

The Quad Operator has a precision DAC output, allowing each operator to output an accurate voltage output signal. This allows calibration without the need for an accurate external reference voltage.

First, patch the module as follows

• OP1 → RATIO 1
• OP2 → RATIO 2
• OP3 → RATIO 3
• OP4 → RATIO 4 & 1V / OCT(Such as Stackable cableNon-buffardDistributed by)
  

Always distribute the OP4 output , not OP1-3 . The calibration process will apply some additional corrections to this distribution. Distribution with a buffer may introduce a small gain that alters the output voltage. Distribution without a buffer is important because it can negatively affect measurements performed during calibration.

Once you have successfully patched the module as described above, trigger the calibration procedure according to the "Cheat Code" below.

• operator1comesFree / LockFlip the switch once
• operator2comesFree / LockFlip the switch once
• operator3comesFree / LockFlip the switch once
• operator4comesFree / LockFlip the switch once
• VCO / LFOQuickly flip the switch 5 times

When the calibration procedure is triggered, the gain LED will flash twice and then return to normal operation a few seconds later.