Paul Davis
45d3ec1437
git-svn-id: svn://localhost/ardour2/branches/2.1-staging@1698 d708f5d6-7413-0410-9779-e7cbd77b26cf
293 lines
12 KiB
XML
293 lines
12 KiB
XML
<?xml version="1.0" standalone="no"?>
|
||
|
||
<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" [
|
||
|
||
]>
|
||
|
||
<section id="sn-configuring-jack">
|
||
<title>Getting Audio In, Out and Around Your Computer</title>
|
||
<para>
|
||
Before you can begin to use Ardour, you will need to get the audio
|
||
input/output capabilities of your system working and properly
|
||
configured. There are two aspects to this process: getting your audio
|
||
interface (soundcard) working, and configuring it to work with the Jack
|
||
Audio Connection Kit (<ulink url="http://jackaudio.org/">JACK</ulink>).
|
||
</para>
|
||
|
||
<section id="sn-jack">
|
||
<title>JACK</title>
|
||
<para>
|
||
It is extremely important to understand that Ardour does not interact
|
||
directly with your audio interface when it is running. Instead, all of
|
||
the audio data signals that Ardour receives and generates are sent to
|
||
and from JACK, a piece of software that routes audio data between an
|
||
audio interface and audio applications, in real time.
|
||
</para>
|
||
|
||
<para>
|
||
Traditionally, most of the audio sources that you would want to
|
||
record, as well as a lot of the more significant effects processing,
|
||
existed outside the computer. Consequently one of the biggest issues
|
||
in integrating a computer into the operation of the studio is how to
|
||
move audio data in and out of the computer.
|
||
</para>
|
||
|
||
<para>
|
||
However, it is becoming increasingly common for studios to use audio
|
||
sources and effects processing that are comprised completely of
|
||
software, quite often running on the same machine as an audio
|
||
sequencer or digital audio workstation (DAW). A new problem arises in
|
||
such situations, because moving audio in and out of the DAW no longer
|
||
involves your hardware audio interface. Instead, data has to be moved
|
||
from one piece of software to another, preferably with the same kind
|
||
of sample synchronisation you’d have in a properly configured
|
||
digital hardware system. This is a problem that has been solved at
|
||
least a couple of times (ReWire from PropellerHeads and DirectConnect
|
||
from Digidesign are the two most common examples), but JACK is a new
|
||
design developed as an open source software project, and is thusly
|
||
available for anyone to use, learn from, extend, *fix or modify.
|
||
</para>
|
||
|
||
<para>
|
||
New users may not initially realize that by using Jack, their computer
|
||
becomes an extremely flexible and powerful audio tool - especially
|
||
with Ardour acting as the ’heart’ of the system.
|
||
</para>
|
||
</section>
|
||
|
||
<section id="getting-audio-working">
|
||
<title>Getting Your Audio Interface Working</title>
|
||
<note>
|
||
<para>
|
||
Although Ardour runs on OS X as well as Linux, this documentation
|
||
describes only a Linux (ALSA) system. The issues faced on OS X tend
|
||
to be entirely different, and are centered mostly on JACK. There are
|
||
also alternative audio device driver families for Linux but they are
|
||
also not discussed here.
|
||
</para>
|
||
</note>
|
||
|
||
<para>
|
||
Getting your audio interface working can be the hardest part of
|
||
setting your computer up to run Ardour, or it could be one of the
|
||
easiest. The level of difficulty you will face depends on the type of
|
||
audio interface ("soundcard") you are using, the operating system
|
||
version you are using, and your own understanding of how it all works.
|
||
</para>
|
||
|
||
<para>
|
||
In an ideal world, your computer already has a working audio
|
||
interface, and all you need do is to start up qjackctl and run JACK.
|
||
You can determine if you face this ideal situation by doing a few
|
||
simple tests on your machine. The most obvious test is whether
|
||
you’ve already heard audio coming out of your computer. If you are
|
||
in this situation, you can skip ahead to
|
||
<xref linkend="selecting-capture-source"/>.
|
||
</para>
|
||
</section>
|
||
|
||
<section id="checking-for-an-audio-interface">
|
||
<title>Checking For an Audio Interface</title>
|
||
<para>
|
||
If you’ve never tried to play audio on your computer before, you
|
||
should use a basic playback program such as play, aplay or possibly
|
||
xmms. Find an audio file on your machine (<command>locate
|
||
.wav</command> may help here), and try to play it. There are several
|
||
possibilities:
|
||
</para>
|
||
|
||
<itemizedlist>
|
||
<listitem>
|
||
<para>
|
||
You may get an error from the program
|
||
</para>
|
||
</listitem>
|
||
|
||
<listitem>
|
||
<para>
|
||
You may hear nothing
|
||
</para>
|
||
</listitem>
|
||
|
||
<listitem>
|
||
<para>
|
||
You may hear something, but its too quiet
|
||
</para>
|
||
</listitem>
|
||
|
||
<listitem>
|
||
<para>
|
||
you may hear something from the wrong loudspeakers.
|
||
</para>
|
||
</listitem>
|
||
</itemizedlist>
|
||
</section>
|
||
|
||
<section id="selecting-capture-source">
|
||
<title>Selecting Capture Source</title>
|
||
<para>
|
||
Many audio interfaces, particularly the cheaper varieties that are
|
||
often found built into computers, have ways to plug in both
|
||
microphones and instruments or other audio equipment to be recorded.
|
||
This immediately poses a question: how does Ardour (or any software)
|
||
know which signal to record, the one coming into the microphone input,
|
||
or the one arriving at the "line in" socket? The same question arises
|
||
also for "high-end" audio interfaces, though in different ways.
|
||
</para>
|
||
|
||
<para>
|
||
The short answer is: Ardour doesn’t. Instead, this is a choice you
|
||
have to make using a program a program that understands how to control
|
||
the mixing hardware on the audio interface. Linux/ALSA has a number of
|
||
such programs: alsamixer, gamix, aumix, kmix are just a few of them.
|
||
Each of them offers you a way to select which of the possible
|
||
recordable signals will be used for as the "capture source". How you
|
||
select the preferred signal varies from program to program, so you
|
||
will have to consult the help documentation for whichever program you
|
||
choose to use.
|
||
</para>
|
||
|
||
<para>
|
||
There are also a few programs that offer ways to control just one
|
||
particular kind of audio interface. For example, the
|
||
<application>hdspmixer</application> program offers control over the
|
||
very powerful matrix mixer present on several RME audio interface.
|
||
<application>envy24ctrl</application> does the same for a number of
|
||
interfaces built around the common ice1712/envy24 chipset, found in
|
||
devices from M-Audio, Terratec and others. Please note that this quite
|
||
similar to the situation for Windows and MacOS users, where each audio
|
||
interface often comes with its own control program that allows certain
|
||
critical configuration choices to be made.
|
||
</para>
|
||
|
||
<section id="problems-with-input-signal">
|
||
<title>"I don’t get any signal when I record …"</title>
|
||
<para>
|
||
The most common problem for first-time audio users on Linux is to
|
||
try to record something and get no signal at all, or alternatively,
|
||
a very low signal. The low signal problem typically arises from one
|
||
or more of the following issues:
|
||
</para>
|
||
|
||
<itemizedlist>
|
||
<listitem>
|
||
<para>
|
||
a microphone input plugged into the "line in" socket of the
|
||
interface. The signal levels delivered by microphones are very
|
||
small, and require amplification before they can be used by most
|
||
audio circuitry. In professional recording studios, this is done
|
||
using a dedicated box called a "pre-amplifier". If your audio
|
||
interface has a "mic input" socket, then it has its own
|
||
pre-amplifier built in, although its probably not a very good
|
||
one. If you make the mistake of plugging a microphone into the
|
||
"line in" socket, you will get either an inaudible or very quiet
|
||
signal.
|
||
</para>
|
||
</listitem>
|
||
|
||
<listitem>
|
||
<para>
|
||
the wrong capture source selected in the audio interface’s
|
||
hardware mixer (see above)
|
||
</para>
|
||
</listitem>
|
||
|
||
<listitem>
|
||
<para>
|
||
the "capture" gain level in the audio interface’s hardware
|
||
mixer is turned down too low. You will need to use a hardware
|
||
mixer application (as described above) to increase this.
|
||
</para>
|
||
</listitem>
|
||
</itemizedlist>
|
||
|
||
<note>
|
||
<para>
|
||
You will notice in the mixer strip for each track in ardour that
|
||
you can change the selection of the monitoring source between
|
||
input/pre/post. Adjusting the fader while watching the ’input’
|
||
levels will NOT have any affect on the levels. As mentioned above,
|
||
ardour is dependent on external mixer settings for a source level.
|
||
</para>
|
||
</note>
|
||
</section>
|
||
</section>
|
||
|
||
<section id="monitoring-choices">
|
||
<title>Monitoring Choices</title>
|
||
<para>
|
||
Its unfortunate that we have to raise this issue at a point in the
|
||
manual where you, the reader, may not even knoiw what "monitoring"
|
||
means. However, it is such an absolutely critical aspect of using any
|
||
digital audio workstation that we need to at least cover the basics
|
||
here. The only people who don’t need to care about monitoring are
|
||
those who will never use ardour to record a live performance (even on
|
||
performed using a software synthesizer).
|
||
</para>
|
||
|
||
<para>
|
||
Monitoring is the term we use to describe listening to what ardour is
|
||
recording. If you are playing a guitar and recording it with ardour,
|
||
you can probably hear the guitar’s own sound, but there are many
|
||
situations where relying on the sound of the instrument is completely
|
||
inadequate. For example, with an electronic instrument, there is no
|
||
sound until the electrical signal that it generates has been processed
|
||
by an amplifier and fed to a loudspeaker. But if Ardour is recording
|
||
the instrument’s signal, what is responsible for sending it to the
|
||
amp+loudspeakers? It can get a lot more complex than that: if you are
|
||
recording multiple performers at the same time, each performer needs
|
||
to hear their own playing/singing, but they also probably need to hear
|
||
some of their colleagues’ sound as well. You might be overdubbing
|
||
yourself - playing a new line on an instrument while listening to
|
||
tracks you’ve already recorded - how do you hear the new material as
|
||
well as the existing stuff?
|
||
</para>
|
||
|
||
<para>
|
||
Well, hopefully, you’re convinced that there are some questions to
|
||
be dealt with surrounding monitoring, see
|
||
<xref linkend="sn-monitoring"/> for more in depth information.
|
||
</para>
|
||
</section>
|
||
|
||
<section id="using-multiple-soundcards">
|
||
<title>Can I use multiple soundcards</title>
|
||
<para>
|
||
There are really lots of great reasons why you should not even attempt
|
||
to do this. But seriously, save your money for a while and buy
|
||
yourself a properly designed multichannel soundcard.
|
||
</para>
|
||
</section>
|
||
|
||
<section id="qjackctl">
|
||
<title>Qjackctl</title>
|
||
<para>
|
||
JACK itself does not come with graphical user interface - to start
|
||
JACK and control it you need to have access to a command line and a
|
||
basic knowledge of Unix-like operating systems. However,
|
||
<ulink url="http://qjackctl.sourceforge.net/">qjackctl</ulink> is a
|
||
wonderful application that wraps JACK up with a graphical interface
|
||
that is both nice to look at and useful at same time. qjackctl is the
|
||
recommended way of using JACK.
|
||
</para>
|
||
<mediaobject>
|
||
<imageobject>
|
||
<imagedata fileref="images/qjackctl.png"/>
|
||
</imageobject>
|
||
</mediaobject>
|
||
<para>
|
||
You should be able to start qjackctl from the “application menu”
|
||
of your system, typically found on the panel/appbar/dock or whatever
|
||
its called that lives at the top/bottom/left/right of your screen.
|
||
</para>
|
||
|
||
<para>
|
||
[ need screenshot of GNOME/KDE/OSX menus here ]
|
||
</para>
|
||
</section>
|
||
<!--
|
||
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude"
|
||
href="Some_Subsection.xml" />
|
||
-->
|
||
</section>
|