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

    ///   - duration: Length of time after the start position to clear
    ///
    public func clearRange(start start: AKDuration, duration: AKDuration) {
        if isAVSequencer { return }

        for track in tracks {
            track.clearRange(start: start, duration: duration)

    ///   - position: Point in time in beats
    ///
    public func addTempoEventAt(tempo bpm: Double, position: AKDuration) {
        if isAVSequencer {
            print("AVSequencer ERROR ! addTempoEventAt only work if not isAVSequencer ")
            return }

        let constrainedTempo = min(max(bpm, 10.0), 280.0)

