Humble Audio - Quad Operator


Yes! After only over 30 years, finally a "one-knob-per-function FM-matrix oscillator (bank)". Sounds complicated? In use it is absolutely hands-on and very quickly understood. It is based on a simple yet ingenious idea: The influence the Operators have on each other is not limited to some pre-wired Algorithms, but can be adjusted freely via a 4*4 routingmatrix. This expands the palette of possible sounds immensely. Add to this the extensive CV-modulation capabilities and you have an enormous FM-playground!



The firmware has been written from scratch by Will Stockwell of Humble Audio for use as a Quad Operator Linear (Thru Zero) FM Matrix. It does have a sound of its own. In the “border areas” it it will exhibit a bit of aliasing, which can be seen as a reminiscence of classic FM-synths. But the Matrix concept alone already offers more freedom than any (hardware) FM-synth we know of. And then there are also the possible connections to the rest of the modular system: Shape, Ratio and Gain can be individually CV-modulated, Pitch (V/Oct) and linear Detune/LF FM (+/-6 semitones) globally. An external audio / oscillator signal can also be integrated into the matrix and modulated in intensity. This input does have a sampling rate of 48kHz, while the others work with 8 kHz max. Tip: You can also feed back the individual outs through the AR FM input!

The free matrix and the possibility to use external signals as an additional operator make the Quad Operator Bank really unique. The closest relative would be the somewhat overlooked Yamaha DX11/TX81Z with which the module shares the number of operators and the ability to generate waveforms other than sine. Four operators are in case of this module not a limitation, but almost an advantage, since with this everything remains in view. With the waveform selection, the adjustable /11 to *11 frequency ratio, the individually controlable level between 0...1 and the CV-modulation of these parameters, the possibilities are already end-le-ssss!

With those degrees of freedom at hand, some of you will yearn for saveable settings (aka algorithms). For this purpose there is the Humble Audio Algo module with which all settings of the module can be stored. Whereby you can crossfade between different settings. Which would be another unique feature and means even moooore possibilities.

All features of the Humble Audio Quad Operator at a glance:

  • One knob per function design for true ease of use
  • Any FM algorithm is possible via modulation matrix
  • The Algo expander provides algorithm save/recall and crossfading capabilities
  • Independent output per operator
  • Virtual VCA per operator for both animating modulation and output volume control
  • Includes a dedicated “AR FM” input with its own modulation sends, designed to bring an audio rate signal in from your rack for use as a modulator. Try processing a phase locked operator, and feeding it back in!
  • Each operator can also be unlocked then tuned and patched independently, making the module a great general purpose oscillator bank. In "Free" (vs. "Lock") the Ratio-Input won't control discrete steps from /11 - *11 anymore, but will become another, continuos V/Oct-Input.
  • Digital, CV-morphable emulation of classic analog waveshapes—sine, triangle, square, and saw
  • In LFO mode, the module enables the generation of up to four phase-locked, complex and interdependent modulation signals

Can be tried and patched and (ab)used at our Showroom as of now!

Audio: AR FM In
CV: Ratio 1-4, Shape 1-4, Gain 1-4, Gain AR FM, 1V/Oct, LF FM, Reset
Audio: Op 1-4
3U Eurorack module, 30HP wide, 25mm deep
Powerconsumption: 140mA +12V, 13mA -12V
0.2 kg
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Status: The article can be picked up in the shop right now / article is ready for dispatch
availability ? immediately available
€ 19% VAT excl. €452.94 € 19% VAT incl. €539.00
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