touch wood

play the furniture

20 HP

Two contact mics on long leads, stuck at either end of a desk, a shelf or a table. Knock on it: the module times the knock reaching each end to find where you hit, hears how hard and with what, and plays your real knock through a tuned bar, low at one end and high at the other.

The TOUCH WOOD panel: black, with two gold fists on a plank table seen from above, about to knock. A gap between the planks runs across the top of the panel: the row of light. Four knobs, GAIN, SPAN, RING and the big BODY, an eight-stop switch, SCALE, a lit button, TEACH, and ten jacks.

Knock: click or tap the surface; come down on it fast for a harder knock. Pick what you knock with above it, and what the pucks are stuck to. Rub: drag on it. From the keyboard: on the surface, A to semicolon knock at ten places from left to right, Shift for a fingernail; the arrow keys move a mark and Space knocks there. TEACH is a button: press it, then knock each end once. Turn a knob: drag it or tap either side of it, roll the wheel over it or use the arrow keys; a double click puts a knob back. SCALE clicks from stop to stop. The patches step on by themselves until you touch something.

A hand knocking a phrase along a desk, a soft beat and a bass. Listen plays the patch from its top; your knocks join in.

example patches

The real one has two contact mics stuck to your furniture. A browser can't feel your desk, so here the surface is a model: how fast a knock runs through it and how it spreads, highs ahead of lows, its echoes off the edges and its ring, and what each thing you knock with does to it. What the module does with the two signals that come out is its engine as designed: it times them to find the place, here as it would on a real desk. The beat and the bass are a stand-in for the rest of a rack.

Where you knock

A knock on a board runs out from where it lands, both ways, and reaches the nearer mic first. The difference between the two arrivals is the place. It never needs to know what the wood is or how far apart the mics are: you teach it.

LEFT, RIGHT: the two pucks' leads plug in here. Any audio works too.
TEACH: press it, then knock each end of the surface once. It lights while it waits; each end of the row lights as it hears it. Move the pucks, teach again.
GAIN: the pucks' preamp, and how soft a knock it hears. Fully right it clips: the room's own hum becomes a fuzz and every knock a crushed slap.
The row: the gap across the top lights where each knock landed, as bright as it was hard, for as long as its bar rings. Its two ends glow with what each mic hears.

The bar

BODY: fully left the bare knock, the desk itself. Noon the knock with a tuned bar ringing under it. Fully right only the bar.
SPAN: how many notes lie across the taught surface. Fully left every knock is the same note, a tuned drum. Fully right four octaves.
SCALE: octaves, fifths, minor pentatonic, major pentatonic, minor, major, phrygian, chromatic, clockwise.
RING: from a dry tick to eight seconds, so knocks stack up into chords.
ROOT: a volt an octave, so a sequencer sets the key.
What with: the bar is struck by your real knock, so a knuckle rings it soft and low and a nail bright. A rub has no place: it bows whatever's ringing.

What comes out

BAR: the knock and the bar, as BODY mixes them.
WOOD L, WOOD R: each mic through the preamp, the surface heard from both ends.
PLACE: the last knock's place, as the note it played, held until the next.
HARD: how hard it was, held.
KNOCK: a trigger on every knock. NAIL: a trigger when it was sharp: a nail, a pen, a coin.

Specs

Format

Width: 20 HP
Controls: 4 knobs, an 8-stop switch, a lit button
Comes with: two contact mics in pucks, on 2 m leads
Finds the place: half of all knocks within 2 to 5 cm of where they land on wood, 4 to 7 on glass; a coin’s within 7

Inputs

LEFT, RIGHT: the pucks, or any audio
ROOT: 1 V/oct

Outputs

BAR: audio, ±5 V
WOOD L, WOOD R: audio, ±5 V
PLACE: 1 V/oct, held
HARD: 0 to 8 V, held
KNOCK, NAIL: triggers, 5 V