         }
     }
 
-    var voiceFileURL: NSURL?
-    var audioPlayer: AVAudioPlayer?
-    var displayLink: CADisplayLink!
-
-    var sampleValues: [CGFloat] = [] {
+    private var voiceFileURL: NSURL?
+    private var audioPlayer: AVAudioPlayer?
+    private var displayLink: CADisplayLink!
+
+    private var sampleValues: [CGFloat] = [] {
         didSet {
             let count = sampleValues.count
             let frequency = 10

        }
    }

    @IBAction func reset(sender: UIButton) {

        state = .Default
    }

        })
    }

    @IBAction private func next(sender: UIBarButtonItem) {

        guard let fileURL = voiceFileURL where !sampleValues.isEmpty else {
            return
