Distinctive sound coming from pub, I note (7)
I believe the answer is:
phoneme
'distinctive sound' is the definition.
(a phoneme is a speech sound)
'pub i note' is the wordplay.
'pub' becomes 'ph' (public house).
'i' becomes 'one' (Roman numeral for one).
'note' becomes 'me' (musical note as in do-re-me).
'ph'+'one'+'me'='PHONEME'
'coming from' acts as a link.
(Other definitions for phoneme that I've seen before include "Unit of spoken sound" , "Small bit of speech" , "distinctive sound" , "minimal piece of speech" .)