"Kapow!" (4)
(Another definition for bam that I've seen is " hoax".)
(Other definitions for bang that I've seen before include "Slam" , "Completely modern" , "Sudden loud noise like an explosion" , "Strike violently" , "drug injection" .)
(Other definitions for wham that I've seen before include "Come down hard on" , "Sound of heavy blow" , "striker may do so" , "Strike -- 1980s' pop group" , "Eighties pop group" .)