Sorry, I can't reproduce your procedure here, because JACK doesn't work in VirtualBox.
Anyway, I can provide you an alternative procedure:
1. Launch VMPK and set the MIDI OUT driver to SonivoxEAS.
2. Close VMPK
3. Launch Fluidsynth with the pulseaudio driver:
$ fluidsynth -a pulseaudio /usr/share/sounds/sf2/default.sf2
4. Launch VMPK.
5. SonivoxEAS uses pulseaudio as well, so you can hear sound, and also use *pavucontrol* to monitor and change the individual volumes.
6. Switch VMPK's MIDI OUT to ALSA.
7. No lockup. You can change the connection to FLUID, and return to SonivoxEAS as many times as you want.
So, it may be a bug in JACK. I don't care either way, because the default Linux audio server is Pulseaudio, in Ubuntu and elsewhere.
As complementary steps, you can:
8. Add to your ".profile" this line, and log-in again:
export JACK_NO_START_SERVER=1
9. Even better: purge JACK from your system.
10. Build Rosegarden without Jack support.
11. Add Pulseaudio to Rosegarden, and make it the default build option.
Regards,
Pedro
On 4/25/20 6:25 AM, Pedro Lopez-Cabanillas wrote:
> Thanks for your message. I've installed Ubuntu 20.04 in VirtualBox, to
> test your observations. Here are my findings...
Ok, I've got it working and I've figured out the procedure to
reproduce the lockup.
1. Launch VMPK and set the MIDI OUT driver to SonivoxEAS.
2. Close VMPK
3. Launch JACK and Fluidsynth.
4. Launch VMPK.
5. Note, no sound, probably because SonivoxEAS is trying to talk to ALSA
and JACK has usurped ALSA/pulseaudio.
6. Switch VMPK's MIDI OUT to ALSA.
7. Lockup.
It's possible this isn't an Ubuntu thing. Might be a legit VMPK issue.
At any rate, I've got a workaround (make sure you switch to ALSA when
JACK/fluidsynth are not running), so I'm good. Let me know if you want
me to do any further testing.
Ted.