JackD, Audio Applications and Ubuntu 14.04 64 bit

Just re-installed Ubuntu 14.04 (this time, the 64-bit version).
I'd already set up my bluetooth speaker: see this post.
The next step was to setup JackD so that I could perform sound / midi editing.

I started QJackCtl, and in settings, configured it to automatically run jackd, and show itself in the systray.  I got the following error when I tried to start the server:

D-BUS: JACK server could not be started

What I needed to do to get the server going was:

aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: HDMI [HDA Intel HDMI], device 3: HDMI 0 [HDMI 0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: HDMI [HDA Intel HDMI], device 7: HDMI 1 [HDMI 1]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: HDMI [HDA Intel HDMI], device 8: HDMI 2 [HDMI 2]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: PCH [HDA Intel PCH], device 0: ALC887-VD Analog [ALC887-VD Analog]
  Subdevices: 0/1
  Subdevice #0: subdevice #0

Here, the list tells me that my output device (Analog port) is card 1, so I need to set the hardware Interface to hw:1 in settings, not hw:0 as follows:

Now when I start QJackCtl, the JackD server launches automagically.

JackD and Friends

QJackControl and its Connections

All JackD applications communicate, and JackD is the process that allows this to happen. QJackControl is a front end to JackD, and allows you to manage what is connected to what.  In this example, you can see that the audio synthesizer is connected to the system (speakers).  In this setup, rosegarden (the Midi player) is connected to the synthesizer on the Midi tab.

So you can connect pretty much anything to anything.  When you get going with multi-channel applications, you can route different channels in different directions - route some channels through sound effects processors, route some instruments out to external Midi hardware players, - almost everything is possible.

This is a screenshot of rosegarden outputting Midi to qsynth, which is passing its output to ardour, where it is being recorded, and also passing its output to the meterbridge, and to the speakers.

JackD Compatible Software Tools

QSynth - Midi synthesis
QTractor - Midi Playing / Editing
Ardour - Multi-track Editing
MeterBridge -  Audio Level Monitoring

RoseGarden - Midi Editing

Other Tools

RipperX - CD Ripping
Audacity - Tempo Change (Change Tempo without Pitch Change, e.g. -50% doubles the track length)
Brasero - CD Burning