Reverb-selected chant

Claim (verbatim)

Reverb-selected chant. RT60 — the time a sound takes to decay by sixty decibels — is the basic figure of architectural acoustics, and a great stone nave can hold a note for many seconds; a fast syllabic melody blurs into mud in such a space, while a slow melisma on a single vowel blooms. Medieval chant repertoires and the churches that housed them were not independent inventions: singers adapted to their rooms across generations. The conjecture is that nave RT60 and repertoire co-evolved — churches with long reverberation should correlate with slower, more melismatic chant, and it is in exactly such buildings that early organum, whose sustained voices exploit a long decay, should first flourish. Measure the surviving Romanesque and Gothic naves, code the local repertoire, and the acoustics should predict the music: the building was a selection pressure on the chant it held.

Prediction clause (verbatim)

For each surviving Romanesque or Gothic church with an attributable local repertoire, measure nave RT60 (mid-frequency) and code the repertoire for tempo and melisma density (notes per syllable) plus the presence of early organum. Primary clause: across churches, RT60 correlates positively with melisma density at r >= 0.3, and churches attested as early organum centres show significantly higher mean RT60 than matched churches without organum. The verdict follows the primary clause.

Kill-dataset (verbatim)

acoustic measurement of Romanesque/Gothic naves vs local repertoire.

Novelty / leakage triage

already answered in the literature

An explicit literature exists on the coevolution of reverberant church interiors and chant: acoustic studies argue liturgy adapted to high reverberation (chant replacing speech), that long reverberation constrains tempo and note duration, and that specific spaces (e.g., Cluny) exalted Gregorian chant — substantially the harvest claim including its directionality.

• 'Why does the acoustic space of churches exalt Gregorian chant?' (ICMC 2005) — Direct acoustic-repertoire study
• 'Acoustics, Liturgy and Architecture in the Early Christian Church' — Liturgy adapting to reverberation
• 'Word and Mystery: The Acoustics of Cultural Transmission During the Protestant Reformation' (PMC) — Architecture-liturgy acoustic coevolution frame

Its literature citations feed the frontier as source leads (3 leads below the evidence/publication boundary, not yet reviewed).

Predictions

No prediction registered yet.