     ///   - position: Point in time in beats
     ///
     public func addTempoEventAt(tempo bpm: Double, position: AKDuration) {
-        if isAVSequencer { return }
+        if isAVSequencer {
+            print("AVSequencer ERROR ! addTempoEventAt only work if not isAVSequencer ")
+            return }
 
         let constrainedTempo = min(max(bpm, 10.0), 280.0)
 

            if isAVSequencer {
                return Double(avSequencer.rate)
            } else {
                return nil
            }
        }
        set {
            if isAVSequencer {
                avSequencer.rate = Float(newValue!)
            }
        }
    }


    /// Get a new track
    public func newTrack(name: String = "Unnamed") -> AKMusicTrack? {
        if isAVSequencer {
            print("AVSequencer ERROR ! newTrack only work if not isAVSequencer ")
            return nil }

        var newMusicTrack: MusicTrack = nil
        MusicSequenceNewTrack(sequence, &newMusicTrack)
