The Acoustic Materials database contains absorption coefficients for hundreds of materials organized by category: porous absorbers (mineral wool, fiberglass, acoustic foam of various densities), membrane constructions, perforated panels, fabrics and drapes, building materials (concrete, brick, drywall, glass), and floor coverings (carpet, hardwood, ceramic tile, linoleum). Coefficients are provided at six standard octave bands: 125, 250, 500, 1000, 2000, and 4000 Hz. Why it matters: an accurate absorption coefficient is the foundation for computing RT60 and planning acoustic treatment. Without reliable material data, all other calculations lose practical meaning. The database lets you quickly compare multiple options and find the material most effective in the required frequency range. How to use: select a category and material to view its coefficients. A frequency range filter helps find materials most effective at low, mid, or high frequencies. Coefficients can be exported to other calculators for use in computations. Common mistakes: choosing a material based on its highest coefficient without considering the frequency — thin foam may have a coefficient of 0.9 at 4000 Hz but only 0.05 at 125 Hz; using published data for non-standard mounting conditions, such as with or without an air gap. Next steps: after selecting suitable materials, proceed to the Treatment Planner or specialized absorber calculators to determine optimal thickness and construction.