{"id": "card_music_tuning", "kind": "reference", "title": "Tuning — equal temperament and the comma", "body": "Twelve-tone equal temperament sets every semitone at the irrational ratio 2^(1/12); it is a deliberate compromise that spreads the Pythagorean comma evenly so every key is playable. A tuning is a CHOICE, not a law of nature.", "source": {"label": "Narrow Highway — music", "url": "", "authority_tier": "engine_derived"}, "shelf": "codex", "box": "music", "bands": ["music", "pillar", "tuning", "one map"], "subject": "Tuning — equal temperament and the comma", "connections": [{"to_card_id": "card_floor_music", "relationship": "part_of", "evidence": "a pillar (Tuning)"}, {"to_card_id": "card_floor_acoustics", "relationship": "connects_at", "evidence": "a tuning divides the octave of frequency - waves"}, {"to_card_id": "card_floor_metrology", "relationship": "connects_at", "evidence": "pitch is a frequency in hertz, built on the SI second"}], "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": ["one map", "pillar", "tuning"]}, "presentation": {"glyph": "•", "kind_label": "music", "by": "Narrow Highway — music", "authority": "engine_derived", "posted": "", "standing": ""}, "neighbors": [{"id": "card_floor_music", "title": "Music — interval, tuning, and the harmonic series", "relationship": "part of", "why": "a pillar (Tuning)", "href": "/card/card_floor_music", "resolved": true}, {"id": "card_floor_acoustics", "title": "Acoustics — waves, loudness, and harmonics", "relationship": "connects at", "why": "a tuning divides the octave of frequency - waves", "href": "/card/card_floor_acoustics", "resolved": true}, {"id": "card_floor_metrology", "title": "Metrology — measurement and the SI", "relationship": "connects at", "why": "pitch is a frequency in hertz, built on the SI second", "href": "/card/card_floor_metrology", "resolved": true}], "house": {"door": "FIND", "kind": "card", "trail": "connections", "seal": "/card/card_music_tuning", "next_step": {"do": "follow a connection: what this card rests on, and what rests on it", "door": "FIND", "tool": "card_connections", "params": {"id": "card_music_tuning"}}, "ends": "a verdict or a card · the trail · a seal · one next step"}}