1. spoke or announced through a megaphone
Usage: past tense of megaphone

Examples

• The coach megaphoned instructions to the players from the sideline.
• Police megaphoned warnings to the crowd to disperse.
• The director megaphoned directions to actors on the distant stage.
• Emergency workers megaphoned evacuation orders throughout the neighborhood.
• The protest organizer megaphoned chants to rally the demonstrators.
• The lifeguard megaphoned safety reminders to swimmers at the beach.