Poem due to be heard (3)
I believe the answer is:
ode
'poem' is the definition.
(ode is a type of poem)
'due to be heard' is the wordplay.
'due' becomes 'owed' (synonyms).
'to be heard' shows a homophone (sound like).
'owed' is a homophone of 'ODE'.
(Other definitions for ode that I've seen before include "A poem celebrating person or event" , "(Railway)system" , "poetry" , "Sung poem" , "Literary work" .)