Beat the drums louder…

… they would beat on the drums in order to drown out the cries of the screaming children.

THE HISTORY OF HINNOM
The name, valley of “the children of Hinnom” or “the son of Hinnom” indicates that perhaps it was originally named after a certain family who lived there.
It was located just south of the city of Jerusalem and was a well-known place to people in Bible times.
No one is quite certain where the name “Tophet” came from or what it means (cf. Jer.19:6; cf. II Kings 23:10).
Many Bible teachers believe that the name comes from the Hebrew word toph, which means “drum.” When the idol-worshippers were sacrificing their little babies to Baal or to Molech, they would put them in the fire and the little babies would scream (II Kings 23:10; cf. Jer.19:5).

As the babies started screaming they would beat on the drums in order to drown out the cries of the screaming children. Therefore, toph or “drum” became “Tophet.” 

http://www.biblebaptistelmont.org/BBC/archive/VALLEY_OF_HINNOM.html