Paul, I agree with Tim Hall's post: Thank you so much for writing such a great software synthesizer. Because you posted on LAU, I hope you don't mind my posting here. Perhaps (esp. with Jack), it may help someone out there... In reading writing XML, I found that it did not behave properly with respect to extensions: In asking to save new.xml, it saved newxml. Also, it could not find newxml because it looked for new.xml for Load. It also seems to load an unknown file when it cannot find anything. That is, instead of displaying "File not found" it seems to load something else. To get Jack to work, I went to src/Output and uncommented the jack_connect lines. I then substituted alsa_pcm:playback_1 and alsa_pcm:playback_2 for alsa_pcm:out_1 and alsa_pcm:out_2. Then it worked for Jack. I did not look at jack_RT. Thanks again, Paul. Very, very nice work. Best regards, Dave.