Tonal working memory is a short-term buffer in your mind that lets you answer the fundamental, repeated question of ear learning: 'did I play the note I just heard?' Unfortunately, this part of your mind is rather delicate, and it doesn't hold very many notes.
I recently added a new top-level section to the Capo product website focused entirely on ear learning—a dedicated space for all my future writing on how to get the most out of Capo when learning songs by ear.
After 13 years of building ear learning software, I thought I understood how musicians learn from recordings. [...] But when I tried to justify why these [new] features would actually help musicians, my foundation started to reveal its cracks.
Capo was not playing audio for some users on Intel Macs running Sonoma. After spending almost two weeks (and about $850) I discovered that macOS Sonoma had a rather nasty bug that was triggered by loading JPEG images.