No sound in Ubuntu (jack/portaudio/alsa mess)

Hi, I'm using Ms in TangoStudio (Ubuntu without pulseaudio, music production derivative). I've tried many different settings (alsa, jack, portaudio, external syntesizer) but I found no stable solution to get the audio working after launching Ms. Either with jack, alsa or portaudio, I dont get sound when push the play button: the program freezes and after restart everything works fine. I have seen around many others have problems with sound under ubuntu. I find it especially important under Ubuntu Studio or TangoStudio, wich are oriented to professional music work. I'm a computer-music teacher, therefore very interested in Musescore stability, I think is a great software for my pupils. Thanks