Loud PA broadcast put on a bigger system (6)
I believe the answer is:
upload
'put on a bigger system' is the definition.
(as in uploading something to the internet)
'loud pa broadcast' is the wordplay.
'broadcast' indicates an anagram.
'loud'+'pa'='loudpa'
'loudpa' is an anagram of 'UPLOAD'.
(Other definitions for upload that I've seen before include "Transfer from a remote computer to yours" , "Transfer (data) to a large computer" , "Transfer 1 Down" , "add data to system" , "Stuff transferred" .)