Yesterday, while taking a short road trip, my iPod Touch (running iOS 15.8.1) stared giving me "headphone safety" notifications, complaining that I’m subjecting myself to dangerous volume levels for an extended period of time.
Yes, the iPod was running at maximum volume for three hours. But not into headphones. The headphone jack was connected to a cable to the car’s AUX audio input, for playback over the car's speakers.
I’ve been doing this for years, but something must have changed recently because I never got these warnings before today. (And they even propagated through iCloud into my phone’s Health app - just to rub it in, apparently).
I eventually found the location to disable this, but contrary to expectation, it’s not located in the "Sounds → Headphone Safety" page of system settings (where the option to "Reduce Loud Sounds" is located), but is instead, in the Accesibility section, for some strange reason. Accessibility → Hearing → Audio/Visual → Headphone Notifications.
I've turned it off. I’ll see if it does anything on my next road trip, where I'll be playing music at 100% volume out the headphone jack into the car stereo for six hours.
h/t: iPhone Life: How to Turn Off Headphone Safety Notifications on iPhone (iOS 17)