Quiet only about the steel tower (5)
I believe the answer is:
pylon
'steel tower' is the definition.
(I've seen this before)
'quiet only about' is the wordplay.
'quiet' becomes 'p' (music symbol for 'piano', ie soft or quiet).
'about' is an anagram indicator.
'only' anagrammed gives 'ylon'.
'p'+'ylon'='PYLON'
'the' acts as a link.
(Other definitions for pylon that I've seen before include "Tower supporting power lines" , "Power cable support" , "Tower for carrying power line" , "Electric grid support" , "Electricity cable support" .)