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 If you plan to use Ardour on Ubuntu, you are <strong>strongly
44 recommended</strong> to download the ready-to-run version from
45 ardour.org. Ardour's lead developer (and many of the most active
46 members of our user community) will not provide support for, and
47 will not investigate bugs reported for, Ubuntu's own packages of
54 If have already installed the Ubuntu package of Ardour and find that
55 although the program starts up and basically runs, but you are
56 running into more subtle problems (for example, with plugin GUIs or
57 with export, or with the use of certain specific plugins), then you
58 are <strong>strongly recommended</strong> to download the
59 ready-to-run version from ardour.org.
64 <h2>Problems with the interaction between PulseAudio and JACK</h2>
67 <dt>Background Info</dt>
70 Like many distributions, Ubuntu has decide to use PulseAudio as the
71 default audio system. PulseAudio is a rich and capable system that
72 provides excellent services for typical users of Linux on the
73 desktop. However, it is not capable of the type of performance that
74 tools like Ardour require and in particular does not offer the
75 possibility of sending audio between applications that can makes the
76 Linux audio environment a very interesting one.
79 This would not a problem if it were not for the fact that JACK will
80 not run correctly (if at all) if it needs to use the same
81 soundcard/audio interface that PulseAudio is using. And since on
82 Ubuntu, PulseAudio is configured by default to always use the
83 (typically single) audio interface on your computer, this is a bit
87 The developers of JACK and PulseAudio got together in 2009 and
88 agreed upon a mechanism by which PulseAudio and JACK could cooperate
89 in their use of a single soundcard. Whether or not PulseAudio is running by
90 default, when JACK starts up it sends out a request to use the
91 soundcard. If PulseAudio is running, it will give up its use of the
92 soundcard to allow JACK to take over (and can optionally be told to
93 route its own audio through JACK). When JACK finishes, it sends out
94 another message, and PulseAudio can once again use the soundcard
98 <dt>What is the problem?</dt>
101 This relatively simple system ought to be the basis for excellent
102 cooperation between PulseAudio and JACK. Unfortunately, it relies on
103 everything being correctly configured for it to work, and Ubuntu
104 have repeatedly failed to get this configuration correct.
107 The specific issues known at this time (spring 2013) are:
109 <li>a bug in PulseAudio that causes it not to give up the
110 soundcard when JACK asks</li>
111 <li>bad package dependency information that causes a critical
112 package to be missing even when JACK and PulseAudio are
114 <li>a bug that causes JACK to freeze up when told to stop,
115 causing issues with restarting</li>
122 <li>Cannot start JACK (though see the next section for other
124 <li>JACK starts but there is no sound coming from Ardour or other
125 applications that use JACK.</li>
134 <h2>Problems with JACK configuration<h2>
137 <dt>What is the problem?</dt>
140 To function as intended, JACK needs to run with access to two
141 operating system facilities called "realtime scheduling" and "memory
142 locking". This means that you, the user who starts JACK, must be
143 allowed access to these facilities. By default, Ubuntu does create a
144 user group that has this permission but ... it does not put new
145 users into this group by default. Consequently, you will not have
146 permission to run JACK in the way you should.
152 A message like "Cannot lock down memory" in the output from JACK as
153 it starts up. This output may be "hidden" in the Messages window of
154 QJackctrl (aka JACK Control), so you should check there.
160 Run the command <code>sudo usermod -a -G
161 audio <em>YOUR-LOGIN-NAME</em></code>. Then logout and login again.