Geometric Acoustics

The Acoustic Mode Map.

A geometric-topology framework that maps the vibration modes of a square plate onto the Lo Shu grid, so mirror positions sing the same pitch and a detuned element announces itself.

Physics is established. The diagnostic is the proposal. Every claim on this page carries its status.

What's established

  • ESTABLISHED

    Chladni plate physics: sand patterns reveal nodal modes.

  • ESTABLISHED

    On an ideal simply-supported square plate, transpose mode pairs (m,n)<->(n,m) are exactly frequency-degenerate (f ∝ m²+n²).

  • ESTABLISHED

    Verified model result: uniform shifts cause zero mirror drift — the check does not false-alarm on global drift.

What we propose

  • PROPOSED

    The Lo Shu allocation as a diagnostic grid: mirror pairs matched, center = fundamental (1,1).

  • PROPOSED

    Detection: mirror drift beyond a per-plate CALIBRATED tolerance flags a detuned or dead element.

  • PROPOSED

    Localization: the drift signature narrows the fault to a symmetry class (up to 8 positions); both plate diagonals are covered by a calibrated absolute-frequency companion check; unique pinpointing requires an asymmetric driver/sensor layout or a scan — state this plainly, it is a feature of our honesty, not a weakness.

  • PROPOSED

    Hilbert-ordered transducer layout (locality, shorter analog traces) and a toroid ring array (360° steering, acoustic vortices) reuse the same geometric backbone as our FPGA power topology.

The honest specs

  • SIMULATED ONLY

    Detectable detune: ~3.6% mass at 0.5% frequency noise; ~0.15% at 0.02%.

  • SIMULATED ONLY

    Class-localization: 93-100% of seeded runs at 4x the detection floor.

  • SIMULATED ONLY

    Blind spots: both plate diagonals (x=y and x+y=1) — companion required.

  • SIMULATED ONLY

    Real plates split degeneracies; the tolerance is calibrated per plate.

Roadmap — tested in public

  1. 01Chladni visualization of the mapped modes.
  2. 02Degeneracy check on a real plate (calibration run).
  3. 03Dead-element detection + symmetry-class localization.
  4. 04Toroid ring: steering + acoustic vortex synthesis.

Every correction public, every model reproducible. Read the one-pager amendment and the verification log.

Continuum Press

We publish engineering truth. Every claim is testable. Every simulation is reproducible. Every correction is visible. Every hypothesis can lose. This is how engineering should be taught. This is how engineering should be published.

Last correction 2026-10-06 · Errata: 2 · Verified runs: 4 · Reader experiments: not tracked (local-only by design).

Fabrication inputs: v3.3 — all five inspection criteria PASS (2026-10-07)

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