Quality found in an aria or a hymn, when done right (7)
I believe the answer is:
harmony
'quality found in an aria' is the definition.
(a musical work might use harmony)
'or a hymn when done right' is the wordplay.
'when done right' is an anagram indicator (the spelling must be corrected).
'or'+'a'+'hymn'='orahymn'
'orahymn' with letters rearranged gives 'HARMONY'.
(Other definitions for harmony that I've seen before include "Mellifluous sound" , "Accord" , "Mutual rapport" , "Pleasing combination of musical notes" , "Source of universe for Dryden" .)