A harp composition by the Spanish artist (7)
I believe the answer is:
raphael
'artist' is the definition.
(Italian painter, 1483-1520)
'a harp composition by the spanish' is the wordplay.
'composition' is an anagram indicator.
'by' is a charade indicator (letters next to each other).
'the spanish' becomes 'el' ('the' in Spanish).
'harp' with letters rearranged gives 'raph'.
'a' put after 'raph' is 'rapha'.
'rapha'+'el'='RAPHAEL'
(Other definitions for raphael that I've seen before include "Italian artist" , "Fifteenth to sixteenth century Italian painter" , "Angel; Italian painter" , "A Renaissance artist" , "Fifteenth to sixteenth century Italian painter/architect" .)