Synonyms of the word 
QUIETENING → CALMING - LULLING - UNALARMING
quietening
- v. present participle of quieten.
- n. The act of making something quieter.
calming
- v. present participle of calm.
lulling
- v. present participle of lull.
unalarming
- adj. Not alarming.
If you are interested in words, visit the following sites :
- wiktionary.org/quietening For complete definition of a word
- 1word.ws/quietening to play with words, suffixs, prefixs, etc.