 
     }
     
-    
     @IBAction func stopPlayAudio(sender: UIButton) {
         // MARK: stop play audio
         stopAudioPlaying()
     }
     
+    
+    func playAudioWithRate(rate: Float){
+        stopAudioPlaying()
+        audioPlayer.rate = rate
+        audioPlayer.play()
+    }
+    
+    func stopAudioPlaying(){
+        
+        audioEngine.stop()
+        audioEngine.reset()
+        
+        audioPlayer.stop()
+        audioPlayer.currentTime = 0
+    }
+    
+    
 
 }
 

        playAudioWithRate(2)
    }
    
    func playAudioWithRate(rate: Float){
        stopAudioPlaying()
        audioPlayer.rate = rate
        audioPlayer.play()
    }
    
    @IBAction func playChipmunkAudio(sender: UIButton) {
        playAudioWithVariablePitch(1000)

        stopAudioPlaying()
    }
    
   
    
    @IBAction func playSlowAudio(sender: UIButton) {
        // MARK: play audio slow
