Hi Fons, thanky you very much for your help! now it works. I was already in the realtime and also in the audio group, in fact, I had modified limits.conf manually when setting up the system, and later, I guess, had also installed the realtime-privileges package. also I checked the priority settings of the jack daemon. Somewhere I read priority should be between 50 and 70 or so. so I had this set already, too; maybe not for every soundcard, though. but, what also seems to be important - quite logically, if I read your recent hints on the realtime-settings - is to tell the jack daemon to run in realtime mode. Here, in qjackctl the related checkbox was unchecked; I did that because I recently tried to start linux with the arch stock kernel instead of the realtime kernel, just to see how this works with my audio usage. And I thought if I don’t run the rt-kernel, I have to uncheck the realtime-setting in qjackctl, which may be a misconception (?). now, with it enabled, zita-ajbridge works very well. again, thank you very much! christoph Am Freitag, den 20.12.2019, 21:49 +0100 schrieb Fons Adriaensen: