Hello, for PEQ to equalize a music stream from a player, it needs to know and track the music stream's audio session id. Unfortunately only a handful of players expose their session id, allowing external EQs to work. Players like Spotify, YouTube music do, but just YouTube app doesn't. However, there is a way to equalize them, you can enable Advanced player tracking from Settings > Advanced player tracking. It uses a way of getting all active sessions via dumpsys but Android restricts that area with a permission (DUMP). You just need to give two permissions, DUMP, which requires a bit of an effort (see this guide on how to activate it), and notification listener permission.