{"id": "card_floor_music", "kind": "note", "title": "Music — interval, tuning, and the harmonic series", "body": "Music is number made audible: the consonant intervals are small whole-number frequency ratios (octave 2:1, fifth 3:2, fourth 4:3), and a scale is a tuning that divides the octave — equal temperament by the irrational 2^(1/12), paying the Pythagorean comma evenly so every key is playable. The interval and tuning arithmetic is already sealed on the music-theory stick, through the engine's music verifier; this floor places music on the map, resting on acoustics (the wave and the harmonic series), metrology (A440, pitch in hertz) and the instruments (the verifier). Taste — whether a chord is beautiful — is declined; the engine seals the ratios, not the beauty. No new stick (tools/seed_music.py).", "source": {"label": "Narrow Highway — music", "url": "", "authority_tier": "engine_derived", "ref": "stick_music_theory_intervals_and_tuning_verified_and_sealed"}, "shelf": "codex", "box": "music", "bands": ["floor", "music", "one map"], "subject": "Music — interval, tuning, and the harmonic series", "connections": [{"to_card_id": "card_music_intervals", "relationship": "has_part", "evidence": "a pillar (Intervals)"}, {"to_card_id": "card_music_tuning", "relationship": "has_part", "evidence": "a pillar (Tuning)"}, {"to_card_id": "card_music_pitch", "relationship": "has_part", "evidence": "a pillar (Pitch)"}, {"to_card_id": "card_k_floor_of_discovery", "relationship": "part_of", "evidence": "music on the one map, rooted in the Floor of Discovery"}], "author": "engine", "created_at": 0.0, "updated_at": 0.0, "visibility": "public", "lifecycle_stage": "public", "volatility": "permanent", "surface": "secular", "generated": false, "call": "codex.music", "facets": {"subject": ["floor", "one map"]}, "presentation": {"glyph": "•", "kind_label": "music", "by": "Narrow Highway — music", "authority": "engine_derived", "posted": "", "standing": ""}, "neighbors": [{"id": "card_music_intervals", "title": "Intervals — the harmonic series in small ratios", "relationship": "has part", "why": "a pillar (Intervals)", "href": "/card/card_music_intervals", "resolved": true}, {"id": "card_music_tuning", "title": "Tuning — equal temperament and the comma", "relationship": "has part", "why": "a pillar (Tuning)", "href": "/card/card_music_tuning", "resolved": true}, {"id": "card_music_pitch", "title": "Pitch — A440 and the measured reference", "relationship": "has part", "why": "a pillar (Pitch)", "href": "/card/card_music_pitch", "resolved": true}, {"id": "card_k_floor_of_discovery", "title": "The Floor of Discovery — one floor, and by its design the fear of God", "relationship": "part of", "why": "music on the one map, rooted in the Floor of Discovery", "href": "/card/card_k_floor_of_discovery", "resolved": true}], "house": {"door": "FIND", "kind": "card", "trail": "connections", "seal": "/card/card_floor_music", "next_step": {"do": "follow a connection: what this card rests on, and what rests on it", "door": "FIND", "tool": "card_connections", "params": {"id": "card_floor_music"}}, "ends": "a verdict or a card · the trail · a seal · one next step"}}