If you are having problems getting the sound to play in realMyst, it could be a setting on your iPad needs to be adjusted. See if the following works to get sound in the game:

 Go to Settings -> General -> Use Side Switch to: and check to see if the switch next to the volume toggle switch is set for Lock Rotation or Mute.  

 If you have the "Use Side Switch for:" setting set for Lock Rotation, double-click the home button and slide the taskbar area from the left to the right to reveal the speaker icon.  Tap the icon to turn the Mute function On or Off.  Then open realMyst - you should have sound now.

 If you have the "Use Side Switch for:" setting set for Mute On/Off, make sure that the switch next to the sound toggle is off.  (Even when Mute is turned on, the toggle for the sound volume still works - you just can't hear it until the Mute button is turned off.) 

 For more information regarding the iPad side switch, please refer to this article: http://support.apple.com/kb/HT4085.

The attached video "iPad No Sound fix" may also help you resolve the issue.

 If you still have no sound after adjusting your settings, please submit a support ticket or email support at support@cyan.com.