hallway by daylight noise

hallway

it's bigger on the inside

20 HP

A reverb made from a real room. Behind the window is a small corridor with a wall that slides and two doors that open. It chirps the room eight times a second, hears what comes back, and that is the reverb. Then SCALE takes the same room past anything that could fit in the house.

The room

It's real. A corridor 22 mm wide and up to 53 mm long, with the panel for a ceiling. A speaker and two microphones look down it, and eight times a second it sends a chirp too quiet to hear and listens to what comes back. The wall and the doors aren't wired to anything. It finds out where they are by listening.

The end wall: the brass puck holds it through the panel with a magnet. Slide it and the corridor runs from 19 to 53 mm, and every echo walks with it.

The doors: each lever is the door's own hinge pin. Barely ajar is the strangest place: a little gets into the room behind and comes back late, slower than the first fall. Wide open it's one bigger room.

Furniture: the window pulls out, and then it's your room. A strip of felt takes the top off the hall. A coin on its edge is the end of the corridor, for most of the sound.

PING, the button and its gate: a tick down the hall, the real room's own sound of it, heard as it is, then the same tick at SCALE.

How big

Architects test halls this way: build a small one, play sound through it fast, slow down what comes back. At 1:8 that's all it does. Past that the measurement's run out of top end, so the top keeps its pitch and only the time stretches: when each echo lands, and how fast each band dies. The hall grows longer and lower and stays as dark.

SCALE, the big knob, and its jack, a volt a doubling: fully left it's 1:1, your sound played in the real box. Half past ten is 1:8, noon about 1:30, three o'clock 1:400. Fully right is 1:8192, nearly half a kilometre, and the first echo takes two and a half seconds.

HANG: how much of what comes out goes back in. Up to noon a longer tail. From three o'clock it howls at the note the room is, and the wall plays it.

CREEP: each measurement reads a little longer than the last, as long as you're playing. The hall sinks and spreads, the strip runs on past the wall, and you can see the wall hasn't moved. PING brings it back to what's there, all at once.

FAR: how far down the hall you stand, from beside the sound to all hall.

AIR: how fast the air takes the top. At noon as measured; fully left it's thick; fully right there's no air at all, and the top rings as long as the bottom.

What comes out

LEFT and RIGHT: the two microphones. There's one speaker in the room, so LEFT and RIGHT in are added.

BACK: a gate when a ping comes home from the end wall. Patch it into PING and the hall keeps time by its own length.

LONG: how long the hall reads, up to 8 V. A slider read by echo, with CREEP's lie in it.

Specs

Format

Width: 20 HP
Controls: a sliding wall, 2 doors, 5 knobs, a button

Inputs

LEFT, RIGHT: audio, ±5 V
SCALE: CV, a volt a doubling
HANG, CREEP: CV, ±5 V
FAR, AIR: CV, ±5 V
PING: gate, rising past 1 V

Outputs

LEFT, RIGHT: audio, ±5 V
BACK: gate, 5 V, 12 ms
LONG: CV, 0 to 8 V