Time invested in some music halls (5)
I believe the answer is:
atria
'halls' is the definition.
(I have seen 'Central halls ' mean 'atria' so perhaps 'halls' could also mean 'atria')
'time invested in some music' is the wordplay.
'time' becomes 't' (abbreviation).
'invested in' indicates putting letters inside.
'some music' becomes 'aria' (aria is a kind of music).
't' going within 'aria' is 'ATRIA'.
(Other definitions for atria that I've seen before include "Lobbies" , "Public spaces with galleries" , "Central courtyards" , "Covered courts" , "Open-roofed entrance halls (Roman) - glass-roofed central halls (modern)" .)