Fresnelcut

Absorber

Perforated-Panel Absorber

A perforated-panel absorber is a sheet drilled with a regular grid of holes over a damped cavity. Like the slat absorber it is a tuned resonant trap, but the round-hole geometry is easy to lay out and cut on any laser or CNC.

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How it works

The holes' open area, the panel thickness, and the cavity depth set the resonance; a porous fill damps and widens it. Fresnelcut picks the geometry for your target band and reports the peak absorption estimate plus the backing materials to buy. It is the drilled-hole sibling of the slat absorber.

The math
f_res = (c / 2π) · √( p / (t_eff · D) )

p = hole open-area ratio, t_eff = effective hole length (with end correction), D = cavity depth.

Best for

  • Low-mid resonance and boxiness
  • A clean, uniform look that's simple to fabricate

Not the tool for

  • High-frequency echo (use a diffuser)
  • Deep bass without a large cavity

Related reading

Related panel types

See all diffuser & absorber types.