Loud enough to destroy speech at arm's length, wet enough to remove the reason not to try.
Four numbers decide what a crowd does: how tightly it is packed, how loud it is, how fast alcohol arrives, and how much attention is available for the people beside you. Everything below is either a published figure or derived from one.
A nightclub is an engineered contradiction. It packs bodies to roughly two per square metre — Fruin grade E, standing room only — which maximises the number of people within reach of each other. Then it plays music at around 100 dB, which collapses the distance at which speech survives to about 75 centimetres: inside Hall's intimate zone. You are surrounded by candidates and can only talk to the one pressed against you.
Alcohol is the third variable, and it is the one that stops the room from being merely uncomfortable. At the rate a club serves, the average person on this floor reaches roughly 38 mg per 100 ml over four hours — close to the window where a controlled group-formation study found social bonding at its strongest. Push the alcohol slider past that window and the model does what the research does: bonding falls away and friction climbs.
The result is the second-highest encounter rate of any room modelled here, and one of the lowest yields per encounter. A club manufactures contact brilliantly and converts it badly, which is exactly what it feels like.
Measured output from a standard run: 1,200 people, 4 hours of venue time, fixed seed, no parameter overrides. Every room on this site is run under identical conditions, so these figures are a like-for-like comparison rather than a set of individually flattering runs.
The crowd is a simulation and is presented as one. What is not invented are its constants: walking speed against density, the proxemic zones, the collapse of speech range with noise, the Widmark blood-alcohol curve and the conversational group limit all come from published work, cited above and listed in full in the engine.
Every gathering below is modelled as this kind of room. Attendance figures are published numbers for the period stated.
At around 100 dB(A), speech stays intelligible only at roughly 75 cm. Talkers raise their voice by about 0.5 dB for every dB of background noise — the Lombard effect — but that never fully compensates, so the conversational distance collapses from Hall's 3.6 m social zone into the intimate zone.
Around 2 people per square metre, which is Fruin Level of Service E: standing room only, movement possible only with the crowd. Walking speed drops from a free 1.34 m/s to roughly 0.61 m/s.
Up to a point. Bonding probability in this model peaks near 0.065 %BAC, following a controlled study where moderate doses increased shared smiling and group formation relative to placebo. Past roughly 0.10 %BAC, motor and speech impairment takes over and the effect reverses.
No. Over a four-hour run of 1,200 people the model records around 42,000 encounters but only 594 lasting ties — well under two percent. Most contact in a club is contact and nothing else.
Each person is one cell with a position, a body mass, a Widmark distribution ratio, an openness trait and a reserve of energy. They walk at the speed the local density allows, drink at the rate the room serves, and when two of them stay within speech range long enough, a bond forms. Most bonds are nothing.
What separates an encounter that creates something from one that does not is whether it bridges two groups that were not previously connected. A tie inside an existing group mostly restates what that group already knows; a tie across a gap carries information neither side had. That distinction is Granovetter's, and it is the mechanic the whole model turns on.
One parameter has no citation and should be read as an assumption: attention, the share of a person available to whoever is beside them rather than to a stage, a road or a rite. It is the variable that separates a street crossing from a dancefloor at similar density, and it is the one this model asserts rather than borrows.
