This is a new bug with R&F. Judging from this reddit comment thread, its a common issue among many users: https://www.reddit.com/r/civ/comments/7x0euc/rise_and_fall_bug_report_megathread/du4pkx7/ Basically, as late game begins, the game starts "losing" more and more sound effects. Sounds & music start glitching out, and then go missing entirely, and eventually nearly the whole game is silent. It behaves sort of like a memory leak, because rebooting the game will restore sound, but only temporarily. After 20 or so turns in late game, the sound starts glitching out again after a reload.