# Decision Record ## Decisions - Readiness is `L2 V5 build-packet candidate`; this repo is organized for review and prototype planning but remains not build-ready. - Treat the instrument as a long bowed single-string study centered on natural harmonics and a buzzing trumpet bridge. - Include sympathetic strings as an optional design branch, not a committed build specification. - Keep every artifact authority at `concept_only` or `pending_measurement`. - Do not create CAD, DXF, tuning tables, harmonic-position tables, bridge dimensions, acoustic predictions, or pressure/force values in this round. - Make the first prototype a buzzing-bridge bench rig rather than a full tromba marina body. - Add `cut-list.csv` as a planning surface for coupons/modules only; it does not authorize cutting stock. ## Open Questions - Which historical tromba marina reference should anchor the next packet? - What body form, string path, and playing posture should define the ergonomic envelope? - What bridge construction creates a controlled trumpet buzz without muting the bowed string? - How should loose-foot buzz be adjusted and reset during setup? - Are sympathetic strings worth including in the first prototype, or should they wait until the main bridge behavior is stable? - What harmonic references help a player without overclaiming a fixed tuning plan too early? - What bench rig can isolate bridge buzz before a full body is designed? - Which measurements are mandatory before choosing body proportions and string scale? - What safety constraints govern a tensioned-string bench fixture? ## Promotion Gates - L3 requires cited reference research, a parameter table, a buzzing-bridge test plan, reviewed CAD or measured drawings, validated bridge/string/ harmonic/structural evidence, and a documented decision about sympathetic strings. - L4 requires physical build data, acoustic observations, setup notes, and measured response from the buzzing bridge.