Possible Clues:

• Deep, ringing and mournful
• Clangorous
• Resonant and mournful
• Resonant and mournful in sound
• Ringing the draughtsman?
• Booming factory hides dope
• Of sound, resonant and reverberating
• After project, chap is mournful
• Loudly lamenting info found in factory
• Dope enters factory, making mournful sound