Axisymmetric thin-shell finite-element model of a bell: the 3D shell is reduced via Fourier-in-theta to a 1D meridian eigenproblem per circumferential order m, solved with a dependency-free Cholesky + cyclic-Jacobi generalized eigensolver. Material params (E, rho, nu, thickness, loss) and geometry drive the partials and decay — not hand-typed ratios. Validated to 0.0% against the analytic ring series (hoop) and free-free beam (meridional bending) via --selftest; C-vs-JS render parity ~1e-8 via compare.mjs. - c/bell.c + c/bell.h: engine + public API; CLI (--note/--material/--geometry/ --modes/--selftest); WAV + modes-JSON export. - bin/viz.mjs: dependency-free software-3D mp4 of the shell deforming by mode (rest -> strike -> ring-out), spectrum HUD, audio muxed via preview-shared. - c/run-c.mjs: pop entry point (mp3 + optional viz); compare.mjs parity harness. - lib/bell.mjs: /pop voice module — renderBell/renderBellMono/bellModes/ bellSampleBank return 48kHz buffers for track renderers (auto-builds engine). - materials.json / geometries.json presets; README with physics + reuse notes. AC OS / menuband wiring is a documented follow-up (same shared-.c pattern as gm_synth.c).