think that fixed it? (with v.2025-09-07) maybe you can try playing that .wav file and see if it works? we're not loading all the song durations in a thread anymore, just loading the current source stream and storing progress as a normalized float 0-1. side note, the values in save data will read slightly differently, so the data isn't totally compatible between, but nothing will break.
Ah, I see it on your website: https://churchbasement.org/#software/tapedeck/main.lua