: Simple frames filled with dense insulation. Efficiency depends on thickness; thicker panels are required to absorb low-frequency standing waves.
: Instead of removing energy, they scatter it in multiple directions using geometric surfaces. This breaks up strong "specular" reflections that cause phase smearing and flutter echo. Acoustic Absorbers and Diffusers Theory Design ...
: These use a grid of blocks at different heights to scatter sound both horizontally and vertically, creating a hemispherical pattern. : Simple frames filled with dense insulation
: Based on number theory, these use wells of varying depths to provide broadband scattering. You can use tools like the QRD Diffuser Calculator to determine well depths for specific frequency ranges. Acoustic Absorbers and Diffusers Theory Design ...
The fundamental difference lies in how they handle sound energy: