AUSTRALIA'S top opera singers performed at the Herald Sun Aria semi-final at Her Majesty's Theatre on Saturday.Held as part of the Royal South Street competitions, the heats attracted 51 entrants from across Australia.Three adjudicators had the tough task of choosing six singers who will perform at the final in Melbourne on October 28.Royal South Street Society vocal committee chairman Peter Zala said it was one of the best semi-finals in recent times with 16 semi-finalists."The adjudicators said all 16 were capable of making a career in opera. The standard was very good," Mr Zala said.He said the Aria had been going since 1924 and the heats and semi-finals were always held at the Ballarat theatre.Semi-Finalists: Jacob Caine, Northcote; Adam Wood, Doncaster East; Samuel Dundas, Prahran; Catriona Bell, Ferntree Gully; Mylinda Joyce, Ruse NSW; Irving Dekterev, Chadstone; Jacqueline Porter, Hampton; Lauren Oldham, Mooroolbark; Anthony Mackey, Fitzroy; Laura Casey, Queenbeyan NSW; Maria Okunev, Carlton; Stacey Alleume, Narre Warren North; Lee Abrahmsen, North Geelong; Natalie Aroyan, East Roseville NSW; Angela Taylor, Altona North; Anna Lucy Whitehead, CoburgFinalists: Catriona Bell, Ferntree Gully; Irving Dekterev, Chadstone; Anthony Mackey, Fitzroy; Natalie Aroyan, East Roseville NSW; Angela Taylor, Altona North; Anna Lucy Whitehead, Coburg.