Indoor concert music arose as the outdoor world grew too noisy

Evidence

Absolute music is disengaged from the external environment and its highest forms (the sonata, the quartet, the symphony) are conceived for indoor performance. Indeed, they seem to gain importance in direct ratio to man’s disenchantment with the external soundscape. Music moves into concert halls when it can no longer be effectively heard out of doors. — Schafer, Murray R, The Soundscape- Our Sonic Environment…, 369

Categorization

• XREF: Connects to the book’s earlier chapters on the industrial soundscape and how noise drove humans to seek refuge. — connects to: A once rich urban natural soundscape has been thinned by development — Pauline Oliveros, Deep Listening, 34
• corroborated: 2 independent passages support this claim — Schafer, Murray R, The Soundscape- Our Sonic Environment…, 369