Stand to project a speech or having done a turn, play guitar? (7)
I believe the answer is:
rostrum
'stand to project a speech' is the definition.
(stand used by a public speaker)
'or having done a turn play guitar?' is the wordplay.
'having done a turn' says the letters should be written in reverse.
'play guitar?' becomes 'strum' (I've seen this before).
'or' written backwards gives 'ro'.
'ro'+'strum'='ROSTRUM'
(Other definitions for rostrum that I've seen before include "stage" , "beak" , "Platform for speaker" , "Raised platform" , "Platform for public speakers" .)