The ADDAC816 Percussion VCA from ADDAC System is a diminutive module combining an envelope with a VCA to accept audio signals and render them, well, percussive. This functionality is all packed onto a faceplate of... [checks notes] 5HP? Bother, nothing interrupts an otherwise perfectly arranged case of modules more than odd numbers; is it too much to ask to shave off one or stretch to six? In any case, I would be more upset about the real estate if the ADDAC816 wasn’t so darn useful.
It features inputs for an audio signal and for triggering its envelope, and two main knobs for envelope gain and decay. There is a toggle switch for short or long decay times, or none (indeed, if desired, the ADDAC816 can behave as a perfectly ordinary VCA). Send it, for instance, white noise, and at its most basic level it’ll instantly create a very passable — and click‑free — drum sound (it’s also fully compatible with tonal sounds, of course). But atop this, several choice functions make for some considerable creative scope.
There is also an Envelope Out jack, meaning you can also send its curve to, for example, a filter for more tonal movement. It’s also possible to modulate the envelope decay time in tandem with an onboard attenuverter and create more organic, expressive responses — I could also feed this input syncopated gates and create quasi‑polyrhythmic patterns. The Envelope Gain circuit is excellent, in that not only does it respond differently to higher voltages in terms of decay length (more voltage means a longer journey back to zero), it can also be used to saturate and distort incoming audio either subtly or to an extremely tasty degree. A gritty parallel for a soft kick drum? Yes please!
This little VCA and envelope combo is supremely useful, especially if you’re working within a small system.
Even if none of the above appeals to you, this little VCA and envelope combo is supremely useful, especially if you’re working within a small system. In that instance I can’t imagine many patches you’d make without it. Another great offering from Lisbon’s finest.