The sort of sound system that's become a cliché (10)
I believe the answer is:
stereotype
'a cliche' is the definition.
(thesaurus)
'the sort of sound system that's' is the wordplay.
'the sort of sound system' becomes 'stereo'.
'that's' becomes 'type' (I am not sure about this - if you are sure you should believe this answer much more).
'stereo'+'type'='STEREOTYPE'
'become' is the link.
Can you help me to learn more?
(Other definitions for stereotype that I've seen before include "Fixed conventionalised image" , "Sort of plate" , "Pigeonhole" , "Set form" , "Stock image" .)