Person who succeeds in broadcasting tune (4)
I believe the answer is:
heir
'person who succeeds' is the definition.
(person who will succeed to property)
'in broadcasting tune' is the wordplay.
'in broadcasting' shows a homophone (sound like) (as it might sound in a radio broadcast).
'tune' becomes 'air' (air can mean a piece of music).
'air' is a homophone of 'HEIR'.
(Other definitions for heir that I've seen before include "Successor to position or estate" , "Successor, next in line" , "One due to inherit" , "One who inherits" , "Acknowledged beneficiary" .)