Fig. 1. Minimoog V modulation matrix.
Compared to acoustic instruments, synths create relatively static sounds—so sonic variations can make the difference between boring and beautiful. Sure, you can switch presets, or add changes in the mix (like crossfading between patches), but making changes in real time—while you record—gives the benefits of a live vibe and an evolving sound.
One way to do this is to morph continuously from one sound to another rather than simply switch presets. The key is assigning a single controller like mod wheel, footpedal, or data slider to change multiple parameters simultaneously. For example, to morph from a sweet background part to a growling lead, you could program the mod wheel to increase distortion, add echo feedback, increase filter resonance, and mix in a sub-octave oscillator. What’s more, you have all the transitional sonic variations between the two end points as options.
For the best morphs, modify as many parameters as needed to make a smooth and dramatic transition. This requires knowing how to assign the mod wheel (or your other controller of choice) to control all those parameters. Most virtual synths use a modulation matrix, where you determine which controller affects which parameter, and by how much (e.g., as you turn up a controller like the mod wheel, positive values raise the assigned parameter value, while negative values lower the parameter value). Here’s how three different virtual instruments handle this task; most instruments work similarly.
Fig. 2. KikAXXE VCF parameters.
Arturia Minimoog V
The modulation matrix (outlined in yellow in Figure 1) is located in the upper left when you “open up” the front panel by clicking on the Open button. In this example, turning the mod wheel 1) raises the cutoff when increased, 2) decreases resonance (emphasis) at higher frequencies, and 3) decreases portamento glide at higher frequencies.
Way Out Ware KikAXXE
Shift-clicking on a parameter brings up a control assignment screen. The section outlined in yellow (Figure 2) shows the screen for VCF resonance, but the screen is identical for all parameters. Mod Wheel is checked as the modulation source, and the green slider sets minimum and maximum values. Invert is checked, so resonance decreases as you increase modulation.
Fig. 3. Rapture’s modulation matrix.
This patch (Figure 3) layers two elements; turning up the mod wheel adds a step-sequenced filter effect to only the second element by 1) increasing Step Generator depth so the filter responds to the generator, 2) reducing the filter cutoff so the step generator covers a wider range, 3) increasing resonance to emphasize the effect, and 4) increasing the step-sequenced element’s level so its sound is more prominent in the mix.