Wall finish? Total interior absorption amount?

Hi all, Studio build in Sydney, Australia here. (5.5m/4m/2.45m H) double control room & live room Quick question regarding control room interior wall "finish"; Should most of the walls be covered in absorption? I read in Rod's book that 20-25% of the total interior surface area acting as absorption is a good amount - does this mean including floors and ceilings, only 20-25% of the interior should be absorptive, and the rest reflective? I see in many studio control rooms have these kind of panels up (see the red/black panels); are these absorption panels (fibreglass wrapped in acoustic cloth)? https://static.wixstatic.com/media/417e ... 0_s_2.webp https://static.wixstatic.com/media/417e ... 0_s_2.webp https://static.wixstatic.com/media/417e ... 0_s_2.webp Many thanks! I really can't find a specific answer to my question, I've searched around the forum & online

Hiya. Without looking it up, I would guess that Rod means 25% visible surface area absorbent. Much of his, and John here, and others' work consists of deep fibre traps with a layer of reflective laths with gaps fronting. So at low LF the whole surface would be pretty absorbent. I cannot view those links. Prosumer studios often use commercial or DIY traps based on the available absorption material. i.e. Semi rigid fibre batts of say 50-100KG, wrapped for obvious reasons. A friend came up with a very neat design. Electrical Tray, Knauf Ecose batts, Bedsheets. You need a little angle grinder to nick triangles out of the tray to get this neat finish and easy build.