Grapes 3D Audio Control: the reference problem

Grapes (Not a Number GmbH) is a VST3/standalone 3D-audio control application that does what A³ Motion does: it sequences movement trajectories for sound objects and sends them over OSC to someone else’s spatial engine (the guide lists, among others, SAD, the IEM plug-ins, L-ISA, d&b Soundscape, Spat GRIS and ADM-OSC). It produces no audio itself. Facts below are paraphrased from its user guide (v1.4.0); the guide is not in this repository — get it from the manufacturer, see sources.

The CDJ is the reference instrument (what the hands know, see CDJ-3000). Grapes is the reference problem: what parameters a trajectory needs, what they are called, what a clip has to be able to do. It is the mature version of A³ Motion’s vocabulary and shows where A³’s terms will have to go.

What to take from it: vocabulary and scope

  • Clips sit in a track × row matrix; a row fires as a scene. A³ Motion has the same shape with four channels and a handful of slots.

  • Clip parameters split in two groups. Perform: speed, speed quantise, offset, fade, direction, trigger mode, finished action, loop mode. Transform: position x/y/z, scale, rotate. A³’s clip settings bar is a subset of Perform — speed, fade, direction and end are the same four ideas.

  • Loop mode is explicit: one shot (plays once, then hands over to the finished action), loop, repeat n times. The finished action then says where control goes: next, previous, first, last, random, jump.

  • Trigger mode is free / bar / beat — scheduling on the next bar is a named setting, not a hidden behaviour. Every transport action also has an “instantly” variant that jumps the queue. That pairing is the important bit: quantised by default, with an override for when the moment will not wait. A³ does the same with SHIFT.

  • Movement presets are geometric (line, triangle, square, circle, spiral, lissajous, waveshaper) plus behaviours (drag, follow, random, swarm, draw, read).

Where it stops being a model

Grapes is a mouse-and-desktop program built for someone sitting down: modifier-plus-scroll quick edits, drag-and-drop onto a trash can, alt-drag to duplicate, collapsible tabs, a zoomable canvas, double-click to type numbers. None of that survives one hand and a touchscreen in the dark.

So take the vocabulary and the feature scope from Grapes, and the interaction from the CDJ. A recommendation of a modifier key or a nested tab because Grapes has one has used it wrong.