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Acoustic diffuser well-depth calculator

Well depths for a cuttable quadratic-residue sound diffuser panel

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Acoustic diffuser well-depth calculator with its default settings

Screenshot of the tool as it opens; it is a real capture, not a mockup.

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What it makes

A table of well depths (1D mode) or block heights (2D skyline mode) for a quadratic-residue acoustic diffuser built from a chosen prime N, design frequency and well width, plus the effective frequency band the panel covers. Exports a cut list PDF with part sizes and quantities for the fins, filler blocks and back panel (or the block heights and counts for the skyline version), and SVG/DXF templates with laser/CNC-standard colours for the back panel and the flat pieces.

How to use it

  1. Start from a quick start — voice and early reflections (the default), low-mid control, a bright room or vocal booth, or the 2D skyline block version — or set your own prime, frequency and width.
  2. Pick a prime N (7, 11, 13 or 17), the design frequency you want the diffuser effective from, and either the well width or the top frequency you want it to reach.
  3. Set the fin thickness (1D mode), back panel thickness, panel height and how many times the sequence repeats across the panel.
  4. Check the stats bar and warnings for well depth, panel size and piece count before cutting.
  5. Download the cut list PDF for part sizes and quantities, and the SVG/DXF for the flat back panel, fin and filler (or block) outlines.

Build notes

  • 1D well depths follow d_n = s_n·λ0/(2N) with s_n = n² mod N and λ0 = speed of sound ÷ design frequency; the 2D skyline heights use s(i,j) = (i²+j²) mod N. Source: T.J. Cox & P. D'Antonio, "Acoustic Absorbers and Diffusers."
  • The lower edge of the effective band is the chosen design frequency; the upper edge is capped by well width (f_max ≈ speed of sound ÷ (2 × well width)).
  • Construction assumes a flat front face: fins run full depth to the deepest well, and shallower wells get a filler block glued at the back so the front stays flush. The skyline version glues blocks of the mapped height onto a flat backer.
  • Works fully offline once opened; nothing is fetched.