Before revision: The siren scene involves competitions where crews compete for the loudest and clearest sound produced by sirens (loudspeakers or public address systems) attached to cars or pushbikes , to win the title of siren king.
After revision: The siren scene involves competitions where crews compete for the loudest and clearest sound produced by sirens (loudspeakers or public address systems) attached to cars or bicycles , to win the title of siren king.