lf

Low-frequency absorber (porous, panel, or resonant) targeting modal peaks/nulls. more

Narrow-band absorber comprising a cavity and neck; frequency set by volume and port geometry. more

Tuned resonant absorber using a limp or stiff panel over an air cavity to target narrow LF bands. more

Porous absorbers become effective near frequencies where thickness ≈ λ/4 (with air-gap considered). more