nx_squeaker_design.nx

nx_squeaker_design.nx -- INVERT the toy model: given the sound you want and the dog that will bite it, return a geometry somebody can mould. Rung R5, and the deliverable of the whole lane. The forward model (nx_squeaker) turns geometry into sound. A product needs the other direction. The Helmholtz law is invertible in closed form, which is why the model was written in millimetres and newtons rather than in convenient normalised units: f = (c / 2pi) * sqrt(A / (V * L)) -> A = (2*pi*f/c)^2 * V * L and the bite sets the shell compliance, because compressing the chamber is what moves the pitch: f_rest^2 / f_bitten^2 = V_bitten / V_rest = (V0 - dVdF * F) / V0 -> dVdF = V0 * (1 - (f_rest/f_bitten)^2) / F So: pick the chamber volume and neck length from what is mouldable, and the neck area and the shell compliance FALL OUT of the target sound and the dog's jaw. Different dogs get different shells for the same sound -- a terrier and a mastiff biting the same geometry do not produce the same pitch, and this is the organ that accounts for that. SOLVED IS NOT VERIFIED. A closed-form solution can be arithmetically perfect and still describe an object that does not work: the neck can come out too small to mould, the shell too soft to survive a chew, the compression beyond what an elastomer will take. So every design is (1) solved, (2) checked against manufacturing limits, and (3) RENDERED through the forward model and measured, with the realised frequency reported next to the requested one. A design that is never rendered is a hope. HONESTY ABOUT THE PREY TARGETS. The target frequencies below are DESIGN TARGETS taken from published ranges for each prey class. They are NOT fitted to measured recordings, because this lane has no licensed reference corpus yet -- see the gap filed against it. Nothing here should be read as "matches a real rabbit"; it means "lands in the band that published work puts rabbit distress in". The distinction matters, and collapsing it is how a lane starts believing its own brochure. license_tier: ORIGINAL expect_exit: 0