whatA hall of clappers, each an oscillator pulled by the sound of everyone else. Fast, eager applause carries a wide spread of tempos; a clapper can period-double into the slow, stately mode -- half the tempo, half the spread.

whyThe claim is Neda's beautiful measurement of real halls: applause self-organizes into rhythmic unison, then breaks it, then finds it again, cyclically. In the fast mode the tempo spread defeats the coupling and the hall is a roar; in the slow mode the spread halves and the same coupling snaps everyone onto one beat. The trap that makes it breathe: unison at half tempo is QUIETER, and applause wants to be loud -- so one by one, patience exhausted, clappers speed up and the beat dissolves. The ledger counts unison spells and prints the signature: coherence and loudness anticorrelated, breathing in opposition. Click to stir the hall back to a roar yourself.

howKuramoto clappers coupled through the mean field of the hall (K 2.1, tempo spread 7 percent, fast tempo 3.6 claps a second); roar fatigue drifts incoherent clappers into the slow mode, and a seeded patience (5 to 14 s of held unison) flips them back fast. The traces overlay coherence and loudness over the last two minutes; everything seeded and fixed-step.