Sound coming from American serving in bar (7)
I believe the answer is:
logical
'sound' is the definition.
(thesaurus)
'american serving in bar' is the wordplay.
'american serving' becomes 'gi' (GI is a term for a US soldier).
'in' indicates putting letters inside.
'bar' becomes 'local' (I've seen this before).
'gi' put within 'local' is 'LOGICAL'.
'coming from' is the link.
(Other definitions for logical that I've seen before include "Well reasoned" , "entirely reasonable" , "In accordance with reason" , "Well-reasoned" , "Objective" .)