@IBAction func onPlayPressed(sender: AnyObject) {
    start()


    isHidden = !isHidden
    UIView.animateWithDuration(0.3) { () -> Void in
        self.setNeedsStatusBarAppearanceUpdate()

}
    self.navigationController?.hidesBarsOnTap = false
    self.navigationController?.setNavigationBarHidden(true, animated: true)

override func viewWillDisappear(animated: Bool) {
    synth.pause()
    vox.pause()

    isHidden = true
    UIView.animateWithDuration(0.3) { () -> Void in
        self.setNeedsStatusBarAppearanceUpdate()

    }
    self.navigationController?.hidesBarsOnTap = false
    self.navigationController?.setNavigationBarHidden(true, animated: true)