The acoustical shape designed by Utzon with Danish and then German acoustic engineers was absolutely clear. The design principle ‘was that, rather than changing the acoustics by absorbing certain unwanted sounds or frequencies, it is better to adjust the physical shape of the hall in such a way that you achieve the perfect acoustical properties
The German firm Cremer and Gabler had designed more than 30 concert halls around the world, including a famous hall in Berlin for Berlin's Philharmonic Orchestra. The design was tested in models made on a scale of 1 to 10 in their laboratory. The adjustment to the physical shape of the hall:
has proved superior to the conventional small size panels since the latter do not reflect the deepest notes from orchestral instruments ...
When I asked the acoustical experts if we should change the shape of the acoustical ceiling further they say, “No, no don't do that because it is perfect, actually it is almost too perfect”.