I see now that Jack is the switchboard for inputs and output devices. I would like the simplest possible test. So far I have the Jack Keyboard as an input. So far as I understand Jack Keyboard is a midi output device. It needs to feed to something that will turn midi into actual waveforms. I have assumed that synthv1 will do this. When I start the Jack gui and then start the Jack Keyboard I can see the connections in the Connections window of the Jack gui: Screenshot_2017-10-06_13-49-01.png Screenshot_2017-10-06_13-49-01.png (28.6 KiB) Viewed 18 times This is in the midi tab of the connections window of the Jack gui. There is still silence when I press the keys of the Jack Keyboard. So something is missing. Do I need to connect the output of synthv1 to an audio output? If I look at the audo tab and open out the Screenshot_2017-10-06_13-53-31.png Screenshot_2017-10-06_13-53-31.png (35.14 KiB) Viewed 18 times synthv1 "readable clients/output ports" out_1 and out_2 to the system playback_1 and playback_2 the Jack Keyboard now makes a sound!! Thank you for letting me flail about in the dark and report such flailing on this forum. Surely there is a resource on the internet for beginners like me that would save so much random trying things? I now feel that ubuntu studio can deliver at least some sound through the Jack system. I will build on what I have done. Yoshimi does not provide an input in the ALSA tab which is where the USB midi signal from the keyboard appears.