The setter is able to sit below Sting in concert hall (8)
I believe the answer is:
barbican
'sting in concert hall' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'the setter is able to sit below' is the wordplay.
'the setter' becomes 'i' (the person that set the crossword).
'is able' becomes 'can' (I've seen this before).
'to' means one lot of letters go next to another (I've seen this in other clues).
'sit below' becomes 'barb' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'i'+'can'='ican'
'ican' after 'barb' is 'BARBICAN'.
Can you help me to learn more?
(Other definitions for barbican that I've seen before include "Watchtower - City of London building complex" , "Walled outwork at the entrance to a fortification" , "London buildings with Arts Centre" , "Watchtower - London arts centre" , "Fortified watchtower over a city gate" .)