I didn't anticipate acoustics to matter, yet perforation patterns, backing materials

https://www.scribd.com/document/1039664098/Copper-Doesn-t-Lie-The-Case-for-Customized-Smokeshaft-Shrouds-and-a-100-Year-Roof-Strategy-208840

I really did not expect acoustics to matter, yet perforation patterns, backing materials, and panel depths in steel ceilings tame echo while maintaining crisp, modern lines.