Not hard, enlisting to play some music (4,9)
I believe the answer is:
easy listening
'some music' is the definition.
(I have seen 'Undemanding music ' mean 'easy listening' so perhaps 'music' could also mean 'easy listening')
'not hard enlisting to play' is the wordplay.
'not hard' becomes 'easy' ('easy' is the opposite to 'hard').
'to play' is an anagram indicator.
'enlisting' with letters rearranged gives 'listening'.
'easy'+'listening'='EASY LISTENING'
(Other definitions for easy listening that I've seen before include "Light, popular music" , "Undemanding music genre" , "Popular music that is tuneful and undemanding" .)