Once in a blue moon you might find that your iPad, iPhone or iPod Touch doesn’t work despite using the volume control rocker and the volume changing on screen. This can be a frustrating problem but luckily it’s fairly simple to fix.
All you need to do is double press the home button to bring up the app switching menu at the bottom of the screen and then swipe your finger to the right to expose the volume and media player controls. You’ll probably find that the volume icon on the far left is muted so just tap it once to unmute and then tap the home button again. Try playing some music or a video and you should find that your sound is now working once again.