Q: Some of my games don’t play audio when my iPhone is in vibrate mode, yet others do. Is there some setting I’m missing here? I’ve tried playing with the volume settings under Sounds and the “Change with Buttons” option, but nothing seems to make a difference.
A: Unfortunately, this is just a matter of improperly designed apps. Basically, Apple makes a distinction for developers between “alert” sounds and normal audio. While the technical term is “APIs” you can basically think of it as two separate audio channels. The ring/silent switch on the iPhone, as well as the Mute switch/button on the iPad, are intended to mute these alert sounds without affecting normal audio. However, if a given app is playing its sound using the wrong API, the switch ends up muting these sounds as well. Sadly, there’s nothing you can do about this other than contact the developer and suggest that the fix their apps.
Essentially, the only sounds that should be silenced when the ring/silent switch is set to silent are notifications and alerts and other related system sounds—basically anything from Notification Center along with phone calls and the other sounds that are listed under “Sound and Vibration Patterns” in Settings, Sounds. The volume for these sounds is also adjusted separately from normal system sounds via the slider shown under “Ringers and Alerts” in the same section.
The “Change with Buttons” option found here controls whether the side volume buttons will also control ringer and alert volume, or only control system volume. This can be a little confusing when enabled, as the function of the button changes depending on whether standard audio is being played or not; when nothing is playing, the side buttons will control the ringer and alert volume, but will dynamically change to controlling the normal audio output volume whenever standard audio is being played from something like the Music or Videos app or a game. The on-screen volume control overlay will display the word “Ringer” in this case to identify that you are adjusting the volume for that audio source.
When this option is OFF, the side buttons will always control normal system audio, and you will have to return to Sounds settings in order to adjust ringer and alert volume.
You can also adjust normal system audio at any time simply by double-tapping the Home button and swiping to the right twice to display a volume slider. This slider will only control normal system audio, regardless of the “Control with Buttons” setting.