The more, the merrier. The Wiard modules seem to be quite expensive, but I got two FracRack-format cheapies, which turned out to have an enormous impact on the realtime tweakability of the modular’s parameters: a nice little joystick and a joystick axis generator. The joystick axis generator is a kind of Modulation Matrix Lite: it takes two input CV’s, and spits them out in various ratios through a number of outputs. Up, down, left, right, and in-between, plus middle and the complement of middle. Patch in a joystick or two LFO’s, connect all the outputs to appropriate inputs, and listen to the sound change drastically and becoming really alive. The JAG comes highly recommended!
