Getting Audio In, Out and Around Your Computer
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 (JACK).
JACK
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.
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.
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.
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.
Getting Your Audio Interface Working
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.
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.
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
.
Checking For an Audio Interface
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 (locate .wav may help here),
and try to play it. There are several possibilities:
You may get an error from the program
You may hear nothing
You may hear something, but its too quiet
you may hear something from the wrong loudspeakers.
Selecting Capture Source
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.
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.
There are also a few programs that offer ways to control just one
particular kind of audio interface. For example, the
hdspmixer program offers control over the very
powerful matrix mixer present on several RME audio interface.
envy24ctrl 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.
Monitoring Choices
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).
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?
Well, hopefully, you’re convinced that there are some questions to be
dealt with surrounding monitoring, see for
more in depth information.
Can I use multiple soundcards
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.
Qjackctl
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,
qjackctl 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.
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.
[ need screenshot of GNOME/KDE/OSX menus here ]