High-pitched soprano damaging after brief time (6)
I believe the answer is:
shrill
'high-pitched' is the definition.
(similar in meaning)
'soprano damaging after brief time' is the wordplay.
'soprano' becomes 's' (musical abbreviation).
'damaging' becomes 'ill'.
'after' is a charade indicator (letters next to each other).
'brief time' becomes 'hr' (short for hour; 'brief' asks for a short form).
'ill' after 'hr' is 'hrill'.
's'+'hrill'='SHRILL'
(Other definitions for shrill that I've seen before include "Loud and high-pitched" , "(Of a cry) piercing" , "High and piercing" , "Of voice, high-pitched and piercing" , "Of sound, piercing and high-pitched" .)