OBSERVATION CHAMBER / MVP
Spectral Drum
Draw a membrane, solve its six lowest vibration modes, choose a strike point, and watch shape change the spectrum and motion.
01 / SHAPE THE MEMBRANE
Editable membrane and computed mode
Advanced diagnostics and solver provenance
| Mode | Eigenvalue | Previous | Delta |
|---|
The full 560-slot mask exceeds the 520-active-cell solve limit and stops without producing eigenpairs.
Observation report
SYSTEM NOTE
On the active cells, the fixed-boundary five-point discrete negative Laplacian solves L phi_k = lambda_k phi_k. A strike at x0 gives modal coefficient c_k = phi_k(x0), and the displayed motion is u(x,t) = sum_k c_k phi_k(x) cos(sqrt(lambda_k) t) over the six computed modes.
OBSERVATION GUIDE
Touchpoints for Observation
Observe a membrane shape become an ordered spectrum, six computed mode fields, and nodal lines.
- Draw or erase the membrane, Solve, select a mode, move the Strike point, and Play the real modal superposition before changing shape and comparing Delta.
- The grid has 560 slots, but dense EVD is limited to 520 active cells; a full mask safely stops.
- Changing the strike point preserves the solved eigenmodes and updates only the coefficients phi_k(x0).
- Eigenvector sign is arbitrary, and repeated eigenvalues are compared through their subspace rather than a single signed vector.
This is a finite 28 x 20 browser membrane with fixed Dirichlet boundaries and six retained modes. It is not an acoustic instrument model, engineering analysis, or a guarantee about a physical membrane.
Runs inside the browser with no upload and no registration.
OBSERVATION POLICY
This observation LAB runs in your browser. It does not upload images, pointer traces, or input.
Route
This chamber belongs to Shape & Space.
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