I thought I really hated this song on Pandora, so I switched the station despite its reliability. The new one started playing Breakfast at Tiffany's but it didn't sound at all the same. It then dawned on me that I had a speaker issue on my iPad, and this might also explain why my mom couldn't understand my FaceTime call earlier in the evening.
Just to check that it wasn't the internet connection, I decided to play songs stored on my iPad. They were bad too. So I blew it out with compressed air. Still sounded terrible.
Finally, I tried that very last trick - turn it on and off. And it worked.
I am sort of pleased but now very irked because I apparently got the one software issue that only messed up my sound, and that screwed up my diagnostics. Also, I don't understand what happened so there is magic and I don't like it.