A type of music not even they can control (7)
I believe the answer is:
operate
'control' is the definition.
(I know that control can be written as operate)
'a type of music not even they' is the wordplay.
'a type of music' becomes 'opera' ().
'not even' means one should take alternating letters (remove even-numbered letters).
The alternating letters of 'they' are 'te'.
'opera'+'te'='OPERATE'
'can' acts as a link.
(Other definitions for operate that I've seen before include "Work - perform surgery" , "(Of machine) function" , "Conduct business in a theatre" , "Make to work" , "Work, function" .)