A brouhaha is a noisy clamourous response to a stimulus, produced by a crowd. It can also refer to the reaction expressed over a period of time to an event. It usually carries negative connotations, the uproar being an utterance of discontent, however it has taken on a milder nuance and a 'brouhaha' may be used to describe a clamour arising for no good reason.

the confused noise of many voices.

a confused disturbance far greater than its cause merits.

loud confused noise from many sources