ABSTRACT
This chapter covers enough detail to understand how acoustic treatments are designed and built and what materials are most effective. Many studio owners and audiophiles install thin acoustic foam all over their walls, mistakenly believing that is sufficient. Porous absorbers such as acoustic foam and fiberglass are velocity absorbers that absorb a broad range, falling off at lower frequencies. However, if recording engineers record vocals, acoustic guitars, or other instruments elsewhere in the room, absorption on nearby opposing walls and the ceiling needed. Acoustic behavior is mostly linear, so whatever happens at low levels happens the same at loud volumes. High-quality acoustic foam of an equal size and shape performs similarly to rigid fiberglass, as does acoustic cotton that’s made from recycled denim. Fiberglass absorbers work by converting acoustic energy to heat, due to friction as the sound waves pass into and through the porous material.
