Tim Mayberry
56e384349b
additions. Add dbhelper.vim key stroke mappings I use for working with docbook source. There are no xsl or css files for customizing the html output so it will look really boring...this will only be temporary. Support for content localization and generation of pdf's is planned. git-svn-id: svn://localhost/ardour2/trunk@1405 d708f5d6-7413-0410-9779-e7cbd77b26cf
195 lines
7.4 KiB
XML
195 lines
7.4 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-monitoring">
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<title>Monitoring</title>
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<para>
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If you are recording an acoustic instrument or voice with no pre-existing
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recorded material as an accompaniment, then you probably don't need to worry
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about monitoring. Just make sure you've made the right
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<link linkend="sn-jack">connections</link> and you should be ready to record
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without reading this section.
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</para>
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<para>
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However, if a musician is playing an instrument (it doesn't matter what
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kind) while listening to some pre-existing material, then it is important
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that some mechanism exists to allow her to hear both her own playing and the
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accompaniment. The same is true in a slightly different way if the
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instrument makes no sound until the electrical signal it creates has been
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amplified and fed to some loudspeakers. Listening to the performance in this
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way is called monitoring.
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</para>
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<para>
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So, if you are recording an electrical or software instrument/signal, and/or
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the musician wants to listen to existing material while performing, then you
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need to ensure that signal routing is setup to allow monitoring. You have 2
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basic choices:
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</para>
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<section id="hardware-monitoring">
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<title>Hardware Monitoring</title>
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<para>
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Hardware monitoring uses the capabilities of your audio interface to route
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an incoming signal (e.g. someone playing a guitar into a microphone) to an
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output connection (for example, the speaker outputs, or a dedicated analog
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monitoring stereo pair). Most audio interfaces can do this, but how you get
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them to do so, and what else they can do varies greatly. We can divide
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audio interfaces into 3 general categories:
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</para>
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<itemizedlist>
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<listitem>
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<para>
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relatively simple, typically stereo, devices that allow the signal being
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recorded to be routed back to the main outputs (most "consumer" audio
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interfaces fit this description, along with anything that provides an
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"AC97-compliant CODEC")
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</para>
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</listitem>
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<listitem>
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<para>
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multichannel devices that allow a given input channel to be routed back
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to its corresponding output channel (the main example is the RME
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Digi9652)
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</para>
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</listitem>
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<listitem>
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<para>
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multichannel devices that allow any input channel, along with any
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playback channel, to be routed to any output channel (the RME HDSP and
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various interfaces based on the envy24/ice1712 chipsets, such as the
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M-Audio Delta 1010, EZ-8 and various Terratec cards)
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</para>
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</listitem>
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</itemizedlist>
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<section id="monitoring-consumer-audio-interfaces">
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<title>"Consumer" audio interfaces and monitoring</title>
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<para>
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For interfaces in the first category, there is no standard method of
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getting the signal routing correct. The variations in the wiring of
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hardware mixing chips, and the capabilities of those chips, means that you
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will have to get familiar with a hardware mixer control program and the
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details of your audio interface. In the simple cases, simply increasing
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the level named "Line In" or "Mic" in the hardware mixer control program
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will suffice. But this is not a general rule, because there is no general
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rule.
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</para>
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<para>
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The following diagram shows a fairly typical AC97-based audio interface
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schematic:
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</para>
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<mediaobject>
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<imageobject>
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<imagedata fileref="images/simplemixer.png"/>
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</imageobject>
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</mediaobject>
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<para>
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Notice:
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</para>
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<itemizedlist>
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<listitem>
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<para>
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there are multiple input connections, but only one can be used as the
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capture source
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</para>
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</listitem>
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<listitem>
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<para>
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it is (normally) possible to route the input signals back to the
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outputs, and independently control the gain for this "monitored" 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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it may or may not be possible to choose the playback stream as the
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capture stream
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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="monitoring-prosumer-audio-interfaces">
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<title>High end "prosumer" interfaces and monitoring</title>
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<para>
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For the only interface in the second category, the RME Digi9652
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("Hammerfall"), the direct monitoring facilities are simplistic but useful
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in some circumstances. They are best controlled using <emphasis>JACK
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hardware monitoring</emphasis>.
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</para>
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<para>
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When using one of the interfaces in the third category, most people find
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it useful to use hardware monitoring, but prefer to control it using a
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dedicated hardware mixer control program. If you have an RME HDSP system,
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then <command>hdspmixer</command> is the relevant program. For interfaces
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based on the envy24/ice1712/ice1724 chipsets, such as the Delta1010,
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Terratecs and others, <command>envy24ctl</command> is the right choice.
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Both programs offer access to very powerful matrix mixers that permit many
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different variations on signal routing, for both incoming signals and the
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signals being played back by the computer. You will need to spend some
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time working with these programs to grasp their potential and their usage
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in different situations.
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</para>
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<para>
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The following diagram gives a partial view of the monitoring schemantics
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for this class of audio interface. Each input can be routed back to any
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output, and each such routing has its own gain control. The diagram only
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shows the routings for "in1" to avoid becoming completely
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incomprehensible.
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</para>
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<mediaobject>
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<imageobject>
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<imagedata fileref="images/matrixmixer.png"/>
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</imageobject>
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</mediaobject>
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</section>
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</section>
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<section id="jack-hardware-monitoring">
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<title>JACK hardware monitoring</title>
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<para></para>
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</section>
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<section id="software-monitoring">
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<title>Software monitoring</title>
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<para>
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Much simpler than hardware monitoring is "software monitoring". This means
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that any incoming signal (say, through a Line In connector) is delivered to
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software (such as Ardour) which can then deliver it back to any output it
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chooses, possibly having subjected it to various processing beforehand. The
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software can also mix signals together before delivering them back to the
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output. The fact that software monitoring can blend together incoming audio
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with pre-recorded material while adjusting for latency and other factors is
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the big plus for this method. The major downside is latency. There will
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always be a delay between the signal arriving at your audio interface
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inputs and it re-emerging from the outputs, and if this delay is too long,
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it can cause problems for the performer who is listening. They will sense a
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delay between pressing a key/pulling the bow/hitting the drum etc. and
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hearing the sound it produces.
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</para>
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<para>
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However, if your system is capable of low latency audio, its likely that
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you can use software monitoring effectively if it suits your goals.
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</para>
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</section>
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<section id="controlling-monitoring-within-ardour">
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<title>Controlling monitoring choices within Ardour</title>
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<para></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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