After Ring compose tune in unenclosed space (4,3)
I believe the answer is:
open air
'unenclosed space' is the definition.
(I've seen this before)
'after ring compose tune' is the wordplay.
'after' says to put letters next to each other.
'ring' becomes 'o'.
'compose' becomes 'pen' (synonyms).
'tune' becomes 'air' (synonyms).
'o'+'pen' is 'open'.
'open'+'air'='OPEN-AIR'
'in' is the link.
(Other definitions for open air that I've seen before include "Outside" , "like 12 [CONCERT] in Hyde Park" , "Uncovered" , "Outdoors - with no cover" , "definitely not in the concert hall" .)