> In iOS I never seen an in-app volume control (I assume its forbidden) and all volume adjustments affect the system volume.

Typically games will have them so you can balance out music and interface sounds relative to in-game sounds.

In my opinion a volume mixer is a requirement for a decent user experience. To reuse the game example: if I want to listen to a podcast while playing, I'd better be able to hear the podcast clearly while also hearing the important sounds from the game.

I will say I find the inconsistency in whether a game will obey the physical Silent switch on iOS to be annoying at times. I'll know I have my volume turned up but oh, this game is being silent because Silent is on. At the very least that should be an option.

While I'm on the Silent gripe, mild tangent, but Facebook on Android refusing to follow the Notifications volume and instead following the Ringtone volume is one of the shittiest pieces of UX I have to deal with daily.

I'm confident it's intentional at this point - they probably A/B tested alternatives and realised this gives them the highest engagement.

Oh, it's painfully obvious that it's intentional, and that's what makes it truly infuriating. I can tolerate a genuine mistake from a developer, no biggie, we're all human, yadda yadda, I *cannot* tolerate Zuckerborg condescendingly ignoring my own decisions and autonomy with my device and asserting that his stupid app is more important than anything else in my life at any given moment.

Gaming with friends online.

1. Upon first open of the game, turn the music volume to off or 10%.

2. Make any other game noise 30% max.

3. Enjoy being able to play and hear game, while also being able to hear friends on Mumble at reasonable volume.

Seems that, since the right volume to adjust is dependent on so many contextual variables, the right thing to do is to display two sliders, one for app & one for the system volume, and let the user adjust the appropriate one.

Cap every app's local volume setting at lowest in use by any app & only allow user to raise volume above this threshold explicitly for currently focused app