Anechoic Chamber Low-Frequency Cutoff Planner

Quarter-wave design rule

Anechoic wedges approximate tapered quarter-wave absorbers. Setting the wedge depth equal to one quarter of the target wavelength ensures energy decays before reaching the rigid wall. The calculator uses the classic relation

with $c$ = 343 m/s indoors and $f$ the design cutoff frequency. The wedge base width $b$ follows from the half-angle geometry:

Once the base is known, dividing the interior surface area by the base footprint estimates the number of wedges. The script assumes full coverage of all six surfaces; adjust results if certain walls use perforated panels or diffusers.

Example wedge demand

The sensitivity table shows how changing the target cutoff frequency alters wedge depth and material volume for a 5 m × 4 m × 3 m room with 45° wedges.

Even though higher cutoffs shorten wedges, the count increases because narrower bases require more pieces to cover the same surface. Use the calculator to evaluate trade-offs between depth, count, and material volume before procurement.