Music producer concerning journalist ahead of publication (4,5)
I believe the answer is:
reed organ
'music producer' is the definition.
(reed organ is a type of musical instrument)
'concerning journalist ahead of publication' is the wordplay.
'concerning' becomes 're' (both can mean on a particular topic).
'journalist' becomes 'ed' (short for editor).
'ahead of' says to put letters next to each other (some letters go in front of others).
'publication' becomes 'organ' (organ is a kind of publication).
're'+'ed'+'organ'='REED-ORGAN'
(Other definitions for reed organ that I've seen before include "Melody Maker?" , "supports traditional services" , "musical instrument" , "What you might hear" , "Keyboard instrument, harmonium" .)