Urban myths held to be exploded in musical style (6,3,5)
I believe the answer is:
rhythm and blues
'musical style' is the definition.
(I know that rhythm and blues is a type of African-American music)
'urban myths held to be exploded' is the wordplay.
'to be exploded' indicates an anagram.
'urban'+'myths'+'held'='urbanmythsheld'
'urbanmythsheld' with letters rearranged gives 'RHYTHM AND BLUES'.
'in' is the link.
(Other definitions for rhythm and blues that I've seen before include "Music style" , "Type of music" , "track in this style for record perhaps" .)