Broadcast acclaims joint position of authority (8)
I believe the answer is:
lordship
'position of authority' is the definition.
'lordship' can be an answer for 'authority' (lordship is a kind of authority). I'm not sure about the 'position of' bit.
'broadcast acclaims joint' is the wordplay.
'broadcast acclaims' becomes 'lords' (I am not sure about this - if you are sure you should believe this answer much more).
'joint' becomes 'hip' (hip joint is a kind of joint).
'lords'+'hip'='LORDSHIP'
Can you help me to learn more?
(Other definitions for lordship that I've seen before include "Dominion - authority" , "Superior state" , "House" , "Supreme power" , "Supreme rule" .)