title: Regulating the volume of SKAction playSoundFileNamed:
body: <p>Is there a way to regulate the volume of sound played via SKAction <a href="https://developer.apple.com/library/iOS/documentation/SpriteKit/Reference/SKAction_Ref/Reference/Reference.html#//apple_ref/occ/clm/SKAction/playSoundFileNamed%3awaitForCompletion%3a">playSoundFileNamed:waitForCompletion:</a>.</p>
  
  <p>I would like to implement a simple music &amp; sound effects slider in my game. I can easily control background music since i play it via AVAudioPlayer, but all sound effects are played via SKAction.</p>