Wiktionary
hush down
vb. 1 (context intransitive informal English) To become quiet; to cease making sounds. 2 (context transitive English) To quieten; to make quiet
Usage examples of "hush down".
Her growl drew such a hush down over the assembly that Alain clearly heard the tick of one of last autumn's dead leaves fluttering down through branches as it fell at long last to earth.
In another moment Fridolin entered at the door and came walking in a deep hush down the middle aisle, with a tall skeleton stalking in his rear.
His voice could roll like thunder or hush down into a zepherlike whisper.