Chaotic noise (6)
I believe the answer is:
hubbub
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">chaotic noise</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for hubbub that I've seen before include "Chaotic noise of crowd" , "General commotion" , "'Brouhaha, uproar (6)'" , "A lot of noise" , "Loud confused noise from many sources" .)