Possible Clues:

• A sound family: good start
• By the sound of it, after a century it separates auld syne
• Repeated word in 'The Trolley Song'
• Go like the clappers, in production of this sound ...
• Resonant sound from family grand
• Metallic, by the sound of it, and it's a century long in Scotland, too
• Be jarring
• Harsh cry a monarch let out by mistake
• Noise from Scots group heading for Glasgow
• See how lenghty this is in Scotland, by the sound of it