Possible Clues:

• Noise of rebel about to leave on the first of the month
• It's quite sound so to bleed about a hundred and one
• Unit of measurement for loudness
• After the first of last month be the last of April by the sound of it
• Unit of intensity of sound
• 'A deep, fierce droning, louder by many -------s than the noise of wasps' (Stella Gibbons, The Shadow of the Sorcerer)
• Applause meter unit
• Bed heaving with lice making a bit of noise
• Sound unit last month initially avoided calumny
• Credible changes when Republican ignored sound measure