Using sound effects with AudioEngine

Question

Background - I saw a video titled "AVAudioEngine in Practice" from the following list of videos published at Apple's recent WWDC to apply sound effects to an audio. https://developer.apple.com/videos/wwdc/2014/

After that, I was successfully able to change the pitch of an audio with the following code:

 //Audio Engine is initialized in viewDidLoad()  audioEngine = AVAudioEngine()  //The following Action is called on clicking a button  @IBAction func chipmunkPlayback(sender: UIButton) {         var pitchPlayer = AVAudioPlayerNode()         var timePitch = AVAudioUnitTimePitch()         timePitch.pitch = 1000          audioEngine.attachNode(pitchPlayer)         audioEngine.attachNode(timePitch)          audioEngine.connect(pitchPlayer, to: timePitch, format: myAudioFile.processingFormat)         audioEngine.connect(timePitch, to: audioEngine.outputNode, format: myAudioFile.processingFormat)          pitchPlayer.scheduleFile(myAudioFile, atTime: nil, completionHandler: nil)         audioEngine.startAndReturnError(&er)          pitchPlayer.play()      } 

From what I understand, I used the AudioEngine to attach the AudioPlayerNode with the AudioEffect, which I in turn attached to the Output.

I am now curious about adding multiple sound effects to the audio. For instance, pitch change AND reverb. How would I go about adding multiple sound effects to the audio?

Also, would it make sense to attach and connect the nodes in viewDidLoad rather than how I have done it here in an IBAction ?

Answer 1

Just connect them.

engine.connect(playerNode, to: reverbNode, format: format) engine.connect(reverbNode, to: distortionNode, format: format) engine.connect(distortionNode, to: delayNode, format: format) engine.connect(delayNode, to: mixer, format: format) 

Answer 2

Background - I saw a video titled "Putting it all together - Intro to iOS App Development with Swift" from the following list of videos published at Udacity to apply sound effects to an audio.

https://youtu.be/XiQfjaYJjuQ

After that, I was successfully able to change the pitch of an audio with the following code:

func playAudioWithVariablePith(pitch: Float){         audioPlayer.stop()         audioEngine.stop()         audioEngine.reset()          let audioPlayerNode = AVAudioPlayerNode()         audioEngine.attachNode(audioPlayerNode)          let changePitchEffect = AVAudioUnitTimePitch()         changePitchEffect.pitch = pitch          audioEngine.attachNode(changePitchEffect)          audioEngine.connect(audioPlayerNode, to: changePitchEffect, format: nil)          audioEngine.connect(changePitchEffect, to: audioEngine.outputNode, format: nil)          audioPlayerNode.scheduleFile(audioFile, atTime: nil, completionHandler: nil)          try! audioEngine.start()          audioPlayerNode.play()      }