If you are not hearing the sounds, then it is probably one of the following.
1) The sound volume on your device might be turned too low or off
2) The mute button on the side of your device might be activated and so your phone/ipad is muted
3) Turn off your orientation lock (toggle the side switch) since this might also cause the audio to be muted even when you set it to lock the screen
4) Update the new settings for your side switch
5) Check the new Command / Control center in iOS 7 that you can activate by swiping up from the bottom of the screen. It also has a new volume control.
The adjustable option is found under “Settings” > “General” where you will find “Use Side Switch to:” which can now be set to either “Lock Rotation” or “Mute.”
Please double check the above. We have over 1 million users and I am not aware of any device where the sound does not work.
PS: If you are one of the lucky few to experience sound problems after checking the above… It turns out that I found another potential solution under a MAC forums thread, and that certain combinations of apps seem to disable sound, regardless of the fact that the settings are set appropriately. I went into settings, where the rocker switch controls rotation. I set the rocker switch to control sound, muted it, then un-muted it. Then I did a system reset (home button plus on/off button on top of iPad simultaneously and hold until see Apple Logo appear, disregarding any interim screens which appear, including welcome screen).