This paper presents a control-systems abstraction of vessel-resonator instruments (exemplified by the ocarina) and derives a general computing primitive: a self-sustaining resonant cell whose behavior is governed by global cavity state, programmable boundary apertures, and gain-controlled nonlinear feedback. The model separates (i) slow structural configuration that shapes resonance and stability margins from (ii) fast energetic control that gates oscillation, regulates amplitude, and modulates lock behavior. From this, we define the Oscillator Compute Cell (OCC): a tunable limit-cycle element whose measurable outputs include frequency, amplitude envelope, phase relationships, and time-to-lock metrics. We show how networks of weakly coupled OCCs can implement low-power analog computation modes such as phase-locked decision patterns, temporal-feature logic, and reservoir-style dynamic encoding. The contribution is a non-device-specific template: computation arises from coherence, thresholds, and attractor selection in coupled nonlinear oscillators, enabling architectures that minimize switching, reduce digitization overhead, and provide “fail-audible” stability indicators. Implementation details are intentionally omitted to preserve non-enabling disclosure while establishing conceptual priority.