Related Clues:

• Knock back door before returning thanks three times
• Rapping sound
• Knocking sound caused by rodent eating a lot of odds and ends
• Knock up cassoulet at a tarty gathering
• Painter and trainee initially see you lifting tap
• Gangster film sound effect
• Revised Maastricht Treaty lacking chemistry — heard repeatedly from knockers
• Gunfire noise
• Snare drum sound
• Drumroll sound
• Speaker finally raised three cheers after which one may enter?
• Rap sound
• Woodpecker sound
• Knock sound
• It's a rap