Titan hiding in downbeat LA suburb (5)
I believe the answer is:
atlas
'titan' is the definition.
(Atlas is an example)
'hiding in downbeat la suburb' is the wordplay.
'hiding' indicates a hidden word.
'ATLAS' is hidden within 'in downbeat la suburb'.
(Other definitions for atlas that I've seen before include "God" , "Titan who supported the heavens" , "Sky carrier - map book" , "The first cervical vertebra" , "book of world records?" .)