Possible Clues:

• Sound grumpy when a right ass is allowed into hotels
• Rising cheer welcoming politician's preparation to speak
• Express grumpy opposition
• In retrospect, 'sound of approval' politician claimed? It's a sound of disapproval
• Self-importantly make a noise as if clearing the throat
• Expression of discontent arrives in sulk before start of holidays
• Mostly annoy university representative, hard to disapprove
• Gruff protest
• Sound disapproving: clueless (but apologetic) trumpeter has arrived
• Mostly firm rear -- hard to express disapproval!