Tim Mayberry
b8a6f94325
Makefile Reformat the docs, I explained in a prior commit why this modifies every file git-svn-id: svn://localhost/ardour2/trunk@1463 d708f5d6-7413-0410-9779-e7cbd77b26cf
293 lines
12 KiB
XML
293 lines
12 KiB
XML
<?xml version="1.0" standalone="no"?>
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<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" "http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" [
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]>
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<section id="sn-configuring-jack">
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<title>Getting Audio In, Out and Around Your Computer</title>
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<para>
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Before you can begin to use Ardour, you will need to get the audio
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input/output capabilities of your system working and properly
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configured. There are two aspects to this process: getting your audio
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interface (soundcard) working, and configuring it to work with the Jack
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Audio Connection Kit (<ulink url="http://jackaudio.org/">JACK</ulink>).
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</para>
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<section id="sn-jack">
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<title>JACK</title>
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<para>
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It is extremely important to understand that Ardour does not interact
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directly with your audio interface when it is running. Instead, all of
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the audio data signals that Ardour receives and generates are sent to
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and from JACK, a piece of software that routes audio data between an
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audio interface and audio applications, in real time.
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</para>
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<para>
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Traditionally, most of the audio sources that you would want to
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record, as well as a lot of the more significant effects processing,
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existed outside the computer. Consequently one of the biggest issues
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in integrating a computer into the operation of the studio is how to
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move audio data in and out of the computer.
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</para>
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<para>
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However, it is becoming increasingly common for studios to use audio
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sources and effects processing that are comprised completely of
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software, quite often running on the same machine as an audio
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sequencer or digital audio workstation (DAW). A new problem arises in
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such situations, because moving audio in and out of the DAW no longer
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involves your hardware audio interface. Instead, data has to be moved
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from one piece of software to another, preferably with the same kind
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of sample synchronisation you’d have in a properly configured
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digital hardware system. This is a problem that has been solved at
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least a couple of times (ReWire from PropellerHeads and DirectConnect
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from Digidesign are the two most common examples), but JACK is a new
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design developed as an open source software project, and is thusly
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available for anyone to use, learn from, extend, *fix or modify.
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</para>
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<para>
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New users may not initially realize that by using Jack, their computer
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becomes an extremely flexible and powerful audio tool - especially
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with Ardour acting as the ’heart’ of the system.
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</para>
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</section>
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<section id="getting-audio-working">
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<title>Getting Your Audio Interface Working</title>
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<note>
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<para>
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Although Ardour runs on OS X as well as Linux, this documentation
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describes only a Linux (ALSA) system. The issues faced on OS X tend
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to be entirely different, and are centered mostly on JACK. There are
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also alternative audio device driver families for Linux but they are
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also not discussed here.
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</para>
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</note>
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<para>
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Getting your audio interface working can be the hardest part of
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setting your computer up to run Ardour, or it could be one of the
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easiest. The level of difficulty you will face depends on the type of
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audio interface ("soundcard") you are using, the operating system
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version you are using, and your own understanding of how it all works.
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</para>
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<para>
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In an ideal world, your computer already has a working audio
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interface, and all you need do is to start up qjackctl and run JACK.
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You can determine if you face this ideal situation by doing a few
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simple tests on your machine. The most obvious test is whether
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you’ve already heard audio coming out of your computer. If you are
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in this situation, you can skip ahead to
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<xref linkend="selecting-capture-source"/>.
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</para>
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</section>
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<section id="checking-for-an-audio-interface">
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<title>Checking For an Audio Interface</title>
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<para>
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If you’ve never tried to play audio on your computer before, you
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should use a basic playback program such as play, aplay or possibly
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xmms. Find an audio file on your machine (<command>locate
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.wav</command> may help here), and try to play it. There are several
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possibilities:
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</para>
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<itemizedlist>
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<listitem>
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<para>
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You may get an error from the program
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</para>
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</listitem>
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<listitem>
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<para>
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You may hear nothing
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</para>
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</listitem>
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<listitem>
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<para>
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You may hear something, but its too quiet
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</para>
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</listitem>
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<listitem>
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<para>
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you may hear something from the wrong loudspeakers.
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</para>
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</listitem>
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</itemizedlist>
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</section>
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<section id="selecting-capture-source">
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<title>Selecting Capture Source</title>
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<para>
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Many audio interfaces, particularly the cheaper varieties that are
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often found built into computers, have ways to plug in both
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microphones and instruments or other audio equipment to be recorded.
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This immediately poses a question: how does Ardour (or any software)
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know which signal to record, the one coming into the microphone input,
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or the one arriving at the "line in" socket? The same question arises
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also for "high-end" audio interfaces, though in different ways.
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</para>
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<para>
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The short answer is: Ardour doesn’t. Instead, this is a choice you
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have to make using a program a program that understands how to control
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the mixing hardware on the audio interface. Linux/ALSA has a number of
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such programs: alsamixer, gamix, aumix, kmix are just a few of them.
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Each of them offers you a way to select which of the possible
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recordable signals will be used for as the "capture source". How you
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select the preferred signal varies from program to program, so you
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will have to consult the help documentation for whichever program you
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choose to use.
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</para>
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<para>
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There are also a few programs that offer ways to control just one
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particular kind of audio interface. For example, the
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<application>hdspmixer</application> program offers control over the
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very powerful matrix mixer present on several RME audio interface.
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<application>envy24ctrl</application> does the same for a number of
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interfaces built around the common ice1712/envy24 chipset, found in
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devices from M-Audio, Terratec and others. Please note that this quite
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similar to the situation for Windows and MacOS users, where each audio
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interface often comes with its own control program that allows certain
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critical configuration choices to be made.
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</para>
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<section id="problems-with-input-signal">
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<title>"I don’t get any signal when I record …"</title>
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<para>
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The most common problem for first-time audio users on Linux is to
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try to record something and get no signal at all, or alternatively,
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a very low signal. The low signal problem typically arises from one
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or more of the following issues:
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</para>
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<itemizedlist>
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<listitem>
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<para>
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a microphone input plugged into the "line in" socket of the
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interface. The signal levels delivered by microphones are very
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small, and require amplification before they can be used by most
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audio circuitry. In professional recording studios, this is done
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using a dedicated box called a "pre-amplifier". If your audio
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interface has a "mic input" socket, then it has its own
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pre-amplifier built in, although its probably not a very good
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one. If you make the mistake of plugging a microphone into the
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"line in" socket, you will get either an inaudible or very quiet
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signal.
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</para>
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</listitem>
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<listitem>
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<para>
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the wrong capture source selected in the audio interface’s
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hardware mixer (see above)
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</para>
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</listitem>
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<listitem>
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<para>
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the "capture" gain level in the audio interface’s hardware
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mixer is turned down too low. You will need to use a hardware
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mixer application (as described above) to increase this.
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</para>
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</listitem>
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</itemizedlist>
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<note>
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<para>
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You will notice in the mixer strip for each track in ardour that
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you can change the selection of the monitoring source between
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input/pre/post. Adjusting the fader while watching the ’input’
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levels will NOT have any affect on the levels. As mentioned above,
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ardour is dependent on external mixer settings for a source level.
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</para>
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</note>
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</section>
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</section>
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<section id="monitoring-choices">
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<title>Monitoring Choices</title>
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<para>
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Its unfortunate that we have to raise this issue at a point in the
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manual where you, the reader, may not even knoiw what "monitoring"
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means. However, it is such an absolutely critical aspect of using any
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digital audio workstation that we need to at least cover the basics
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here. The only people who don’t need to care about monitoring are
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those who will never use ardour to record a live performance (even on
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performed using a software synthesizer).
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</para>
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<para>
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Monitoring is the term we use to describe listening to what ardour is
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recording. If you are playing a guitar and recording it with ardour,
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you can probably hear the guitar’s own sound, but there are many
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situations where relying on the sound of the instrument is completely
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inadequate. For example, with an electronic instrument, there is no
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sound until the electrical signal that it generates has been processed
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by an amplifier and fed to a loudspeaker. But if Ardour is recording
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the instrument’s signal, what is responsible for sending it to the
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amp+loudspeakers? It can get a lot more complex than that: if you are
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recording multiple performers at the same time, each performer needs
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to hear their own playing/singing, but they also probably need to hear
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some of their colleagues’ sound as well. You might be overdubbing
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yourself - playing a new line on an instrument while listening to
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tracks you’ve already recorded - how do you hear the new material as
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well as the existing stuff?
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</para>
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<para>
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Well, hopefully, you’re convinced that there are some questions to
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be dealt with surrounding monitoring, see
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<xref linkend="sn-monitoring"/> for more in depth information.
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</para>
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</section>
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<section id="using-multiple-soundcards">
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<title>Can I use multiple soundcards</title>
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<para>
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There are really lots of great reasons why you should not even attempt
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to do this. But seriously, save your money for a while and buy
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yourself a properly designed multichannel soundcard.
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</para>
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</section>
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<section id="qjackctl">
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<title>Qjackctl</title>
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<para>
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JACK itself does not come with graphical user interface - to start
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JACK and control it you need to have access to a command line and a
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basic knowledge of Unix-like operating systems. However,
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<ulink url="http://qjackctl.sourceforge.net/">qjackctl</ulink> is a
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wonderful application that wraps JACK up with a graphical interface
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that is both nice to look at and useful at same time. qjackctl is the
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recommended way of using JACK.
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</para>
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<mediaobject>
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<imageobject>
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<imagedata fileref="images/qjackctl.png"/>
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</imageobject>
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</mediaobject>
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<para>
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You should be able to start qjackctl from the “application menu”
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of your system, typically found on the panel/appbar/dock or whatever
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its called that lives at the top/bottom/left/right of your screen.
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</para>
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<para>
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[ need screenshot of GNOME/KDE/OSX menus here ]
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</para>
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</section>
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<!--
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<xi:include xmlns:xi="http://www.w3.org/2001/XInclude"
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href="Some_Subsection.xml" />
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-->
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</section>
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