It is still impossible to change audio volume for headphones before the app begins playing.
Consider this scenario:
- Use iphone at max volume to power speakers (pseudo line-out)
- Switch to sensitive IEM's later, attempt to change volume before starting... can't. Just changes notification volume.
- Begin playing music, rupture eardrum if IEM's in.
Fortunately iphone doesn't push enough current to damage the hardware (which can be replaced), but it is plenty enough to damage hearing (which can't be replaced).
I have yet to find a way to change headphone volume without initiating playback.
Android's volume control is a mess but at least it is possible to change these volumes.
Blackberry 10 handles the situation best: It remembers the volume for line-out usage and remembers the headphone volume used last. If Apple can detect headphones are unplugged they can detect line impedance vs. headphone impedance.
(There is a setting in Settings that will turn off ringer volume changes with the buttons. That way you will always adjust the volume and never the ringer, no matter whether anything is playing or not. As such you can then adjust the volume of headphones without playing anything with the buttons. Works like a charm. I find that I personally never need to adjust the ringer volume once I have set it to an appropriate level. I just care about turning the ringer off and on, not adjusting the volume.)
I also think Apple already does remember headphone volume? It seems to for me?!
You can plug in the headphones then adjust volume from the control center. I do this habitually after experiencing several near eardrum blowouts as your describe.
What I do is slide up the tray from the bottom, and then very carefully, turn down the volume slider, making sure not to accidentally hit the play button.
Consider this scenario:
- Use iphone at max volume to power speakers (pseudo line-out)
- Switch to sensitive IEM's later, attempt to change volume before starting... can't. Just changes notification volume.
- Begin playing music, rupture eardrum if IEM's in.
Fortunately iphone doesn't push enough current to damage the hardware (which can be replaced), but it is plenty enough to damage hearing (which can't be replaced).
I have yet to find a way to change headphone volume without initiating playback.
Android's volume control is a mess but at least it is possible to change these volumes.
Blackberry 10 handles the situation best: It remembers the volume for line-out usage and remembers the headphone volume used last. If Apple can detect headphones are unplugged they can detect line impedance vs. headphone impedance.