Humble Audio Quad Operator FM Synthesizer made easy for Eurorack
FM synthesis tends to remain a complex mystery for the most part and yet we all enjoy messing about with it. The Quad Operator brings the most useful parameters to the surface in an attempt to open up the magic of FM to exploratory fingers.
The module looks clean, complex and largely unlabelled which is a bit disconcerting until you realise that it’s just 4 identical sets of controls, 1 for each of the 4 operators. The first 3 knobs going left-to-right are the basic Ratio, Detuning and Shape of the operator wave. There are digital emulations of sine, triangle, square and saw waveforms. The other 4 knobs labelled Mod 1-4 along the top are modulation routings so each operator can become a modulator of any other operator. This way you can create some very complex routings to generate some very interesting sounds.
In regular FM synthesis you have algorithms that set up the routing of the operators. In the Quad Operator there are no algorithms and instead the routing is completely open on the matrix of 16 knobs. This makes it so much simpler and intuitive to use. For the essential “Feedback” parameter you simply set the operator modulating itself. It’s really quite wonderful.
For envelopes, you have individual Gain inputs on each operator along with CV control over each Ratio and Shape. The operators then have their own individual outputs.
In the simple run-through video (below) it’s remarkable how straight forward it all seems to be. It makes FM somehow obvious and intuitive which is something it is rarely accused of. There are endless tonal possibilities available here even if the module itself doesn’t look particularly exciting.
The Quad Operator should be available now for $500.
- Humble Audio website.