         
         // MARK: play audio slow
         stopButton.hidden = false
-        audioPlayer.currentTime = 0
         audioPlayer.rate = 0.5
         audioPlayer.play()
     }

        
        // MARK: play audio fast
        stopButton.hidden = false
        audioPlayer.currentTime = 0
        audioPlayer.rate = 2
        audioPlayer.play()
    }

        audioEngine.reset()
        
        audioPlayer.stop()
        audioPlayer.currentTime = 0
    }
    
    @IBAction func playSlowAudio(sender: UIButton) {
