Sambuca A modern boat-shaped arched harp inspired by the Royal Cemetery of Ur, c. 2600 BC. SAM-13-ROOT prototype + parametric family of five variants.

Tony Koop · Heifer Zephyr · Fall 2026 capstone target

[HERO-01 — SAM-13-ROOT three-quarter on stand, soft directional light]
photo to be captured per photo-shotlist.md

What this is

The sambuca is a modern reinterpretation of the Sumerian boat-shaped arched harp recovered from the Royal Tombs at Ur. The original artifact — British Museum object 121198 — survives only as gold tuning pegs, lapis lazuli decorative fragments, and Woolley's field sketches; the wood is a 1971–72 reconstruction from contemporary cylinder-seal depictions. That gives the modern build a 4500-year-old visual fingerprint — boat hull, curved cantilever neck, gold-flared cap, multi-strip lapis seam band, row of bulb tuning pegs with cord wraps — and full design freedom on every dimension underneath.

Inspired by the pattern. Not a reproduction. Not a claim of cultural authority over any modern living tradition.

Family spec

ID	Body	Strings	Tuning	Harness	Role
SAM-13-ROOT	650 mm	13	G3 → E5	none	build target
SAM-19-MID	850 mm	19	D3 → G5	low-back belt	mid concert
SAM-25-CONCERT	1050 mm	25	A2 → A5	sax harness	concert
SAM-13-AE	650 mm	13	G3 → E5	none + piezo	acoustic-electric
SAM-13-MULE	650 mm	13	G3 → E5 (reduced T)	none	tension test mule

All five share one parametric MasterLayout part. body_length_mm and string_count drive the configurations.

Design fingerprint

Eight visual elements that read as Sumerian sambuca:

Gold-flared cap at the neck top.
Row of 13 bulb-headed tuning pegs with visible cord wraps.
Strong J-curve neck meeting the body at the stern.
Multi-strip lapis band (5 parallel strips) along the soundboard-hull seam.
Brass collar at the neck-body joint.
Slim boat hull with pronounced bow lift.
Rectangular pale inlay panel at the bow end of the soundboard.
Two integral stub blocks at the stern keel.

What's modern

Soundhole at the keel, not the soundboard — projects sound forward toward the listener.
Geared guitar tuners hidden inside the neck, behind PVD-gold-tone bulb caps and decorative cord wraps.
Modern strings — fluorocarbon trebles + wound nylon basses, 65–80 kgf calibrated total.
CNC fabrication for the hull, neck, inlay program, and stand.
Japanese kanawa-tsugi joinery on the stand — a stylistic choice, not Sumerian.

Build timeline

Active build: 60–90 hours over 6–10 weeks, plus a 30-day MULE tension hold before SAM-13-ROOT is brought to full tension.

Stage 1

Hull (walnut, CNC-from-block or stave-laminated). Wall thickness verified to 6 ± 0.5 mm at midship, bow, stern.

Stage 2

Neck (sapele 3-laminate, CNC sweep). Highest-risk structural member.

Stage 3

Soundboard (3 mm Western red cedar, fan-braced, inlay pockets cut).

Stage 4

Scarf joint + brass collar. The single most critical joint.

Stage 5

Soundboard installation. Multi-strip lapis inlay + bow-end inlay panel filled.

Stage 6

Keel port cut (80 × 50 mm oval, 15° forward tilt).

Stage 7

Stand (CNC-curve-profiled walnut cradle with kanawa-tsugi joinery).

Stage 8

Tuners + decorative cord wraps + PVD-gold bulb caps. Fingerprint complete.

Stage 9

String-holder strip + prototype voicing on SAM-13-MULE. voicing gate

Stage 10

SAM-13-MULE 30-day tension hold, then SAM-13-ROOT gradual stringing to 65–80 kgf. release gate

Stage 11

Final voicing + acoustic measurement (SPL, frequency response, Helmholtz check).

Stage 12

Documentation + brand integration + cultural-advisor review. release gate

Acoustic study

Hull volume on the SAM-13-ROOT is ~3.8 L — small for a 13-string instrument. The Wolfram notebook (wolfram/sambuca-acoustics-starter.wl) predicts:

Cavity Helmholtz with the 80 × 50 mm keel port: ~143 Hz.
First soundboard plate mode (cedar @ 3 mm): ~160 Hz.
Coupled cavity-plate pair: ~125 Hz / ~185 Hz.
Bass strings (G3 → C4) sit just above the lower coupled mode — the voicing sweet spot for arched harps with small cavities.

Provenance & cultural language

The sambuca pattern is rooted in early Mesopotamian musical instruments from the Royal Cemetery at Ur (~4500 years old, unambiguously public domain). The Greek term sambykē (σαμβύκη) is a later (Hellenistic) word, historically debated as a possible descendant of the Sumerian form; the build adopts the modern term while acknowledging the etymological uncertainty.

Inspired by the Sumerian pattern. Not a reproduction of any specific surviving artifact. Not a recreation of any reconstructed instrument such as BM 121198. Not a claim of cultural authority over any modern living tradition.

Release gates

This repo stays in PRIVATE REVIEW until:

Cultural / musicology advisor review — sign-off on the provenance language above and on imagery attribution across the deck and site.
SAM-13-MULE tension and joint validation — successful 30-day neck-deflection hold at MULE tension with ≤ 2 mm deflection.
Heifer Zephyr brand integration — placement option A (soundboard inlay) or B (stand-only) locked.

Repo map

README.md — entry point.
reverse-engineering.md — source-material analysis.
design.md — design intent, soundhole strategy, cultural language, brand options.
family-spec.csv — five-variant table.
risks.md — red-team risk register.
bom.csv · sourcing.csv · cut-list.csv · validation.csv — tables.
assembly-manual.md — 12-stage build sequence.
supplier-rfq.md · drawing-brief.md · visual-bom-brief.md · photo-shotlist.md — process docs.
cad/SAM-000_master-equations.txt — global equations (single source of truth).
cad/SW-MIGRATION-CHECKLIST.md — SolidWorks rebuild plan.
cnc/cnc-plan.md — pre-CAM operation plan.
wolfram/sambuca-acoustics-starter.wl — acoustic study notebook.
harness/README.md — SAM-19 / SAM-25 harness designs.
capstone-deck.pptx · print-packet.pdf — capstone artifacts.
learn-to-play/ — placeholder; populated by the sheet-music skill after tuning is locked.

Related repos

kora — parametric template adopted as the MasterLayout pattern.
fujara → moseno — earlier Pack-and-Go variant precedent.
instrument-showcase — portfolio entry point.