The Treatment Planner helps you design the placement of absorbers and diffusers in a room and immediately see how it affects reverberation time. You specify room dimensions and current surface materials, then add treatment panels one by one: porous absorbers, bass traps, membrane panels, Helmholtz resonators, or diffusers — on any wall, floor, or ceiling. The planner recalculates RT60 after each addition. Why it matters: individual calculators show the characteristics of a single absorber but not the overall picture of its impact in the context of the room. The planner accounts for the cumulative effect of all treatment elements, displays RT60 curves "before" and "after" by octave band, and warns if the room risks becoming over-damped — sounding unnaturally dry. How to read results: compare the RT60 curves before and after treatment. The target range depends on room purpose — the planner highlights zones where reverberation time falls outside recommended limits. The placement diagram clearly shows the coverage percentage of each surface. Common mistakes: placing all absorbers on one wall only; using thin 20 – 30 mm panels to address low-frequency problems; ignoring first reflection points; trying to deaden the entire room instead of applying balanced, targeted treatment. Next steps: calculate specific absorber types with the dedicated calculators and estimate treatment cost using the ROI estimator.