How it works
The slots and the air behind them form a resonator tuned by the slot ratio, panel thickness, and cavity depth. A porous fill or fabric facing in the cavity broadens and damps the peak. Fresnelcut solves the cavity depth for your target frequency and emits the backing bill of materials so the result is reproducible. See diffuser vs absorber for when each one is the answer.
f_res = (c / 2π) · √( ε / (t_eff · D) )ε = slot open ratio, t_eff = effective slot depth (with end correction), D = cavity depth.
Best for
- Low-mid boom and boxiness (roughly 100–500 Hz)
- A treated wall that still looks like furniture
Not the tool for
- High-frequency echo and liveliness (use a diffuser)
- Deep bass below ~80 Hz (needs a much deeper cavity)