sonorousness vs timbre

sonorousness and timbre both are nouns.

Word	Noun	Adjective	Verb	Adverb
sonorousness	Yes	No	No	No
timbre	Yes	No	No	No

As nouns, timbre is a hypernym of sonorousness; that is, timbre is a word with a broader meaning than sonorousness:

sonorousness: having the character of a loud deep sound; the quality of being resonant
timbre: (music) the distinctive property of a complex sound (a voice or noise or musical sound)

Other hypernyms of sonorousness include quality, timber, tone.

sonorousness (noun)	timbre (noun)
having the character of a loud deep sound; the quality of being resonant	(music) the distinctive property of a complex sound (a voice or noise or musical sound)