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diff --git a/manual/xml/jack.xml b/manual/xml/jack.xml new file mode 100644 index 0000000000..8798a45686 --- /dev/null +++ b/manual/xml/jack.xml @@ -0,0 +1,292 @@ +<?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> |