7 Ubuntu Linux is the most popular variety of Linux in use on desktop
8 and laptop systems. It has the backing of a for-profit corporation
9 (Canonical Inc.) behind it, a defined philosophy and a huge and
10 worldwide user base. As a result, it is a common platform for people
11 who want to use Ardour and other tools for music creation and
15 Unfortunately, Ubuntu has repeatedly caused major headaches for
16 people who want to use Ardour. These problems have arisen from a
17 combination of two basic issues:
20 <li>Badly built packages of Ardour</li>
21 <li>Poor system configuration related to JACK, which Ardour (and
22 most other pro-audio tools on Linux) uses for audio and MIDI I/O.
27 <h2>Problems with Ardour Packages</h2>
30 <dt>What is the problem?</dt>
33 It is not possible to know whether the current package of Ardour
34 released by Ubuntu has been correctly built or not. Ubuntu has a
35 history of making packaging errors that lead to crashes, missing
36 functionality and odd behaviour that is not present in the
37 ready-to-run version of the program that you can get from ardour.org
38 (or in the packages released by other distributions)
43 Ardour starts up and basically runs, but you encounter subtle
44 problems (for example, with plugin GUIs or with export, or with the
45 use of certain specific plugins), or are missing functionality, or
52 Download the ready-to-run version from ardour.org. Ardour's lead
53 developer (and many of the most active members of our user
54 community) will not provide support for, and will not investigate
55 bugs reported for, Ubuntu's own packages of Ardour. The ardour.org
56 packages install along side your distribution versions, and do not
57 interfere or interact in anyway other than sharing your own personal
58 Ardour settings and configuration choices.
63 <h2>Problems with the interaction between PulseAudio and JACK</h2>
66 <dt>Background Info</dt>
69 Like many distributions, Ubuntu has decide to use PulseAudio as the
70 default audio system. PulseAudio is a rich and capable system that
71 provides excellent services for typical users of Linux on the
72 desktop. However, it is not capable of the type of performance that
73 tools like Ardour require and in particular does not offer the
74 possibility of sending audio between applications that can makes the
75 Linux audio environment a very interesting one.
78 This would not a problem if it were not for the fact that JACK will
79 not run correctly (if at all) if it needs to use the same
80 soundcard/audio interface that PulseAudio is using. And since on
81 Ubuntu, PulseAudio is configured by default to always use the
82 (typically single) audio interface on your computer, this is a bit
86 The developers of JACK and PulseAudio got together in 2009 and
87 agreed upon a mechanism by which PulseAudio and JACK could cooperate
88 in their use of a single soundcard. Whether or not PulseAudio is running by
89 default, when JACK starts up it sends out a request to use the
90 soundcard. If PulseAudio is running, it will give up its use of the
91 soundcard to allow JACK to take over (and can optionally be told to
92 route its own audio through JACK). When JACK finishes, it sends out
93 another message, and PulseAudio can once again use the soundcard
97 <dt>What is the problem?</dt>
100 This relatively simple system ought to be the basis for excellent
101 cooperation between PulseAudio and JACK. Unfortunately, it relies on
102 everything being correctly configured for it to work, and Ubuntu
103 have repeatedly failed to get this configuration correct.
106 The specific issues known at this time (spring 2013) are:
108 <li>a bug in PulseAudio that causes it not to give up the
109 soundcard when JACK asks</li>
110 <li>bad package dependency information that causes a critical
111 package to be missing even when JACK and PulseAudio are
113 <li>a bug that causes JACK to freeze up when told to stop,
114 causing issues with restarting</li>
121 <li>Cannot start JACK (though see the next section for other
123 <li>JACK starts but there is no sound coming from Ardour or other
124 applications that use JACK.</li>
133 <h2>Problems with JACK configuration</h2>
136 <dt>What is the problem?</dt>
139 To function as intended, JACK needs to run with access to two
140 operating system facilities called "realtime scheduling" and "memory
141 locking". This means that you, the user who starts JACK, must be
142 allowed access to these facilities. By default, Ubuntu does create a
143 user group that has this permission but ... it does not put new
144 users into this group by default. Consequently, you will not have
145 permission to run JACK in the way you should.
151 A message like "Cannot lock down memory" in the output from JACK as
152 it starts up. This output may be "hidden" in the Messages window of
153 QJackctrl (aka JACK Control), so you should check there.
159 Run the command <code>sudo usermod -a -G
160 audio <em>YOUR-LOGIN-NAME</em></code>. Then logout and login again.