Ringing sound in prison (5)
I believe the answer is:
clink
This clue is a triple definition!
'ringing' is the first definition.
(thesaurus)
'sound' is the second definition.
(clinking is a kind of sounding)
'in' acts as a link.
'prison' is the third definition.
(the clink can informally mean prison)
(Other definitions for clink that I've seen before include "Prison - knock glasses together" , "Old London prison" , "Rattle of coins; prison (slang)" , "Sound made when hitting glass" , "1 ac [COOLER]" .)