Related Clues:

• Megaphone sound
• Be loud
• Loud, harsh sound
• Play loudly, as a 53-Down
• Make a harsh sound
• Bugler's blast
• Prime Minister on the radio? Blast!
• Screeching from Red Robbo's employers many years back
• Clamour created by ex-PM in speech
• Siren noise
• Lay on, as a horn
• Blast, as a boom box