9 Ubuntu Linux is the most popular variety of Linux in use on desktop
10 and laptop systems. It has the backing of a for-profit corporation
11 (Canonical Inc.) behind it, a defined philosophy and a huge and
12 worldwide user base.As a result, it is a common platform for people
13 who want to use Ardour and other tools for music creation and
17 Unfortunately, Ubuntu has repeatedly caused major headaches for
18 people who want to use Ardour. These problems have arisen from a
19 combination of two basic issues:
22 <li>Badly built packages of Ardour</li>
23 <li>Poor system configuration related to JACK, which Ardour (and
24 most other pro-audio tools on Linux) uses for audio and MIDI I/O.
29 <h3>Problems with Ardour Packages</h3>
32 <dt>What is the problem?</dt>
35 It is not possible to know whether the current package of Ardour
36 released by Ubuntu has been correctly built or not. Ubuntu has a
37 history of making packaging errors that lead to crashes, missing
38 functionality and odd behaviour that is not present in the
39 ready-to-run version of the program that you can get from ardour.org
40 (or in the packages released by other distributions)
45 If you plan to use Ardour on Ubuntu, you are <strong>strongly
46 recommended</strong> to download the ready-to-run version from
47 ardour.org. Ardour's lead developer (and many of the most active
48 members of our user community) will not provide support for, and
49 will not investigate bugs reported for, Ubuntu's own packages of
56 If have already installed the Ubuntu package of Ardour and find that
57 although the program starts up and basically runs, but you are
58 running into more subtle problems (for example, with plugin GUIs or
59 with export, or with the use of certain specific plugins), then you
60 are <strong>strongly recommended</strong> to download the
61 ready-to-run version from ardour.org.
67 <h3>Problems with PulseAudio and JACK Configuration</h3>
69 <h4>Problems with the interaction between PulseAudio and JACK</h4>
72 <dt>Background Info</dt>
75 Like many distributions, Ubuntu has decide to use PulseAudio as the
76 default audio system. PulseAudio is a rich and capable system that
77 provides excellent services for typical users of Linux on the
78 desktop. However, it is not capable of the type of performance that
79 tools like Ardour require and in particular does not offer the
80 possibility of sending audio between applications that can makes the
81 Linux audio environment a very interesting one.
84 This would not a problem if it were not for the fact that JACK will
85 not run correctly (if at all) if it needs to use the same
86 soundcard/audio interface that PulseAudio is using. And since on
87 Ubuntu, PulseAudio is configured by default to always use the
88 (typically single) audio interface on your computer, this is a bit
92 The developers of JACK and PulseAudio got together in 2009 and
93 agreed upon a mechanism by which PulseAudio and JACK could cooperate
94 in their use of a single soundcard. Whether or not PulseAudio is running by
95 default, when JACK starts up it sends out a request to use the
96 soundcard. If PulseAudio is running, it will give up its use of the
97 soundcard to allow JACK to take over (and can optionally be told to
98 route its own audio through JACK). When JACK finishes, it sends out
99 another message, and PulseAudio can once again use the soundcard
103 <dt>What is the problem?</dt>
106 This relatively simple system ought to be the basis for excellent
107 cooperation between PulseAudio and JACK. Unfortunately, it relies on
108 everything being correctly configured for it to work, and Ubuntu
109 have repeatedly failed to get this configuration correct.
112 The specific issues known at this time (spring 2013) are:
114 <li>a bug in PulseAudio that causes it not to give up the
115 soundcard when JACK asks</li>
116 <li>bad package dependency information that causes a critical
117 package to be missing even when JACK and PulseAudio are
119 <li>a bug that causes JACK to freeze up when told to stop,
120 causing issues with restarting</li>
127 <li>Cannot start JACK (though see the next section for other
129 <li>JACK starts but there is no sound coming from Ardour or other
130 applications that use JACK.</li>
139 <h2>Problems with JACK configuration<h2>
142 To function as intended, JACK needs to run with access to two
143 operating system facilities called "realtime scheduling" and "memory
144 locking". This means that you, the user who starts JACK, must be
145 allowed access to these facilities. By default, Ubuntu does create a
146 user group that has this permission but ... it does not put new
147 users into this group by default. Consequently, you will not have
148 permission to run JACK in the way you should.
154 A message like "Cannot lock down memory" in the output from JACK as
155 it starts up. This output may be "hidden" in the Messages window of
156 QJackctrl (aka JACK Control), so you should check there.
162 Run the command <code>sudo usermod -a -G
163 audio <em>YOUR-LOGIN-NAME</em></code>. Then logout and login again.