Go and visit the cathedral.
Just recently it has had a A$30 million upgrade. This mainly a new roof and replacement of part of the old structure.
As with the rest of Perth, the meld of old and new is stunning and certainly does not detract from the look of the building.
The accoustics I cannot comment about as I heard no music when I was there, I just hope they have not been ruined.
Admire the historical architecture of St Mary's Cathedral. The Murray Street end of the Cathedral was built in 1965. The sancturay and transepts at the eastern end was built in 1930.