Resonant sound made by family group? Good! (5)
I believe the answer is:
clang
'resonant sound' is the definition.
(I've seen this before)
'by family group? good' is the wordplay.
'by' says to put letters next to each other.
'family group?' becomes 'clan' (I've seen this in another clue).
'good' becomes 'g' (abbreviation).
'clan'+'g' is 'CLANG'.
'made' acts as a link.
(Other definitions for clang that I've seen before include "Make a loud metallic noise" , "Loud resonant metallic sound" , "Ring like a bell" , "Resounding effect" , "Dull sound of a bell" .)