If no one know were is the problem in this function I will write it without using BList::SortItem(..). PS 1 : Matthijs you do a really hard stuff for understanding Midi2 and writing all the documentation. The world will remenber you ;-) PS 2 : But now the bad news of the week : I haven't the knowledge for writing the Midi 1 Synth (How make PitchShifting and add reverb in real time? I think I can do all other things on this class but there is not a lot of other things :-( A+ Jerome