Composer broadcast towering study (5)
I believe the answer is:
haydn
'composer' is the definition.
(I know that Haydn is an composer)
I can't explain the remainder of the clue.
(Other definitions for haydn that I've seen before include "Austrian symphonist, d. 1809" , "Josef --, prolific composer" , "The Surprise symphony composer, d. 1809" , "Composer of over 100 symphonies" , "Creation composer" .)