Piece of music is not a soul track primarily (5)
I believe the answer is:
nonet
'piece of music' is the definition.
(I've seen this before)
'not a soul track primarily' is the wordplay.
'not a soul' becomes 'none' (both can mean nobody).
'primarily' suggests taking the first letters.
The initial letter of 'track' is 't'.
'none'+'t'='NONET'
'is' is the link.
(Other definitions for nonet that I've seen before include "Band of nine?" , "Composition for nine voices" , "Tonne (anag.); music for a group" , "baseball team" , "Ennead" .)