High CPU load with ZynAddSubFX


i’m running Ardour 5.8.0 on KXStudio (14.04). I have two ZynAddSubFX plugins: One from falkFX (the man behind KXStudio) and one from ZynAddSubFX.

With the first one (falkFX) I don’t get any sound and with the second one the CPU is rising to infinity even when I don’t play anything.

Any ideas what might be wrong here?

Solved: It works with the falk version without CPU load. Midi was not enabled.