AVAudioplayer: Volume drops after couple of seconds

问题

I've implemented an audioplayer on iOS 10.2.1 with XCode Version 8.2.1 (8C1002) on Mac OS Sierra 10.12.3

When the song starts playing the volume drops quite a bit after a couple of seconds.

Has anyone experienced such an effect?

 do {
     myAudioPlayer = try AVAudioPlayer(contentsOf: url!)
     myAudioPlayer.prepareToPlay()
     myAudioPlayer.volume = 1.0
 } catch  {
     print(error)
 }

来源：https://stackoverflow.com/questions/43076669/avaudioplayer-volume-drops-after-couple-of-seconds