Concept note · the lab vocabulary
Spatial surface
A surface made of watched air: it is there because a sensor says so, and the hand is told it was hit.
What it is
A playing or working surface that has no material. A sensor defines a region of empty space — a ring, a plane, a band — and anything that crosses it counts as touching it. What the material used to give back, the feel of striking it, is supplied by the thing that strikes: the tool in the hand pushes back at the moment of contact.
In the lab
- AirDrums →
- Six micro-drones each hold a LiDAR ring where a drumhead or cymbal would be; a spring and a voice coil inside the stick kick it back when its tip crosses a ring — a whole kit with no stands, in one case.
Our position
Most of an instrument's bulk exists to hold a few surfaces in place. Take the surfaces out of matter and the holding goes with them: the surface can be put anywhere, moved, tilted or packed away in seconds. Two things have to stay true for it to work. The surface must be where the player expects it, every time, so the sensors that draw it must agree with each other; and the strike must feel like a strike, so the response has to arrive in the hand, inside the few milliseconds a player notices.
Honest limitations
A spatial surface gives back only what is built into the tool that strikes it — a stick can rebound, but a hand gets nothing, and a brush or a rimshot has no obvious meaning. The surface is only as steady as the sensors that hold it, and several sensors watching the same air interfere with each other; that has to be designed for rather than wished away. AirDrums is a concept specification; none of this is yet proven in hardware.
The experiments are the proof
Every claim in this note is made concrete somewhere in the lab — the idea exists because the machines needed it.
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