Possible Clues:

• Have a canyonlike effect
• Come back again and again, by the sound of it
• Repeated sound of tree-chopping
• Repeat again
• Might the sound of a cheer get round once more?
• Again reverberate
• One gets a return from this, by the sound of it
• Repeat sound (a second time?)
• Wild cheer end of grotto makes resonate
• Bounce off the walls continuously