Don't hear any sound? Can't adjust the sound? Here's what to check.
There are a variety of ways to alter the volume of SlingPlayer on an iPad, iPhone or iPod touch. If you're having trouble adjusting the volume on your device, read on!
SlingPlayer for iPhone or iPod touch
Double-check that the sound in SlingPlayer is adjusted to what you want. Just tap the screen and move the slider to the left or the right.

This slider also works independently of the Ring/Silent switch on the side of the iPhone and second generation iPod touch models. Changing the Ring/Silent switch to Silent won't silence SlingPlayer.
SlingPlayer for iPad
There is no volume slider in SlingPlayer for iPad, so the iPad hardware volume buttons are how you'll adjust the volume for the application:

Are there other volume controls available when using SlingPlayer?
The MISC menu contains a number of other functions & options - depending on your remote, you may find additional volume controls for your A/V device(s) there:

Also, if your device has been updated to iOS 4.2 or higher, you can double-click the iOS device Home button to access the system volume while using SlingPlayer. You may need to swipe left or right to get to the volume controls - check out your device documentation for more on how to access these iOS controls. The system volume controls look like this on an iPad:

Note that this technique may disconnect your stream - just single click the Home button to return to SlingPlayer and reconnect to your Slingbox.