 
     /// 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)

    ///
    public func setLoopInfo(duration: AKDuration, numberOfLoops: Int) {
        if isAVSequencer {
            //nothing yet
        } else {
            for track in tracks {

    ///   - duration: Length of time after the start position to clear
    ///
    public func clearRange(start start: AKDuration, duration: AKDuration) {
        if isAVSequencer {
            print("AVSequencer ERROR ! clearRange only work if not isAVSequencer ")
        return }

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