Heard location of spectacle (5)
I believe the answer is:
sight
'spectacle' is the definition.
(spectacle can mean a sight or display)
'heard location' is the wordplay.
'heard' indicates a 'sounds like' (homophone) clue.
'location' becomes 'site' (site is a kind of location).
'site' sounds like 'SIGHT'.
'of' is the link.
(Other definitions for sight that I've seen before include "Aiming device on gun" , "something ugly" , "Place worth visiting" , "Field of vision" , "Device used in aiming" .)