[LAU] latency issue

Hi all, I have tons of xruns and sound saturation in some specific case. I use freewheeling + zynaddsubfx. The connexions in qjackctl are specific : - my external midi keyboard is connected to freewheeling midi in. - freewheeling midi out connected to zynaddsubfx midi in. - zynaddsubfx audio out connected to freewheeling audio in - freewheeling audio out connected to alsa_pcm The reason for this strange connexion is because I use my midi keyboard to perform some freewheeling actions, but freewheeling has to pass the non-relevant midi event it gets to zyn (the notes I play). It is this kind of loop (freewheeling, to zyn, back to freewheeling) that cause the xruns !! I mean that if I connect my midi keyboard directly to zynaddsubfx and zynaddsubfx audio out to freewheeling audio in, then it is ok !! But, I really need to control freewheeling too from the midi keyboard. BTW, the problem does not appear with the first connexions I described, if instead of playing from the midi-keyboard, I play from zynaddsubfx integrated visual keyboard. Anyone experiencing the same problem? Any idea? Thank you very much !