How does a harmonium work?

Every note on a harmonium is a thin brass tongue buzzing through a slot, fed by air you pump with one hand. An Indian harmonium is a wooden box with a keyboard on top and a hinged bellows at the back.

Read how it works: How does a harmonium work? · The history of the harmonium · More boxes on Glassbox

Chapters in this interactive model

1. A box of brass reeds and a bellows: Keys, valves, reeds, stops and two bellows: follow the air.
2. A brass tongue that chops the air: Every note is a tiny springboard swinging through a slot.
3. Pump, store, squeeze: A spring-loaded reservoir turns uneven pumping into steady wind.
4. Pull a stop, add a voice: Bass, male and female reeds, a sharp musette and humming drones.
5. Twelve fixed notes, and the notes in between: Equal temperament, pure intervals, and the scale changer.
6. From church organ to every stage in India: Pumped with one hand, played on the floor, heard in every kind of music.