Hawk-headed god restrained outside produces trumpet (6)
I believe the answer is:
herald
'trumpet' is the definition.
(thesaurus)
'hawk-headed god restrained outside' is the wordplay.
'hawk-headed god' becomes 'ra' (Egyptian god).
'restrained' becomes 'held' ('hold' can be a synonym of 'restrain').
'outside' indicates putting letters inside.
'ra' going inside 'held' is 'HERALD'.
'produces' is the link.
(Other definitions for herald that I've seen before include "Signal the arrival of" , "Person who announces important news" , "Presage for old announcer" , "Announcer - forerunner" , "Harbinger, precursor" .)