----
-layout: default
-title: Using More Than One Audio Device
----
-
-<p>
- Ardour will only ever deal with a single <dfn>audio device</dfn>. If you
- want to use more than one, you have two choices:
-</p>
-<ul>
- <li>
- If you want to use Ardour to start JACK (which handles all
- audio I/O) you will need to create a "fake" audio device on your
- computer the represents all the multiple devices you wish to
- use. How to do this is platform dependent and described below.
- </li>
- <li>
- Use a different tool to start JACK and manage all the devices.
- </li>
-</ul>
-<p>
- Ardour is fundamentally designed to be a component in a
- pro-audio/music creation environment. Standard operating practice
- for such setups involves using only a single digital <dfn>sample
- clock</dfn> (something counting off the time between audio samples).
- This means that trying to use multiple independent soundcards is
- problematic, because each soundcard has its own sample clock, running
- independently from the others. Over time, these different clocks
- <dfn>drift</dfn>
- out of sync with each other, which causes glitches in the audio. You
- cannot stop this drift, although in some cases the effects may be
- insignificant enough that some people might not care about them.
-</p>
-<p>
- Thus in an ideal world you should not use multiple independent
- soundcards but instead use a single device with a single clock and all
- the inputs, outputs and other features that you need.
-</p>
-<p>
- Of course, a lot of people don't live in an ideal world, and believe
- that software should make up for this.
-</p>
-
-<h2>OS X</h2>
-<p>
- In CoreAudio, <dfn>aggregate devices</dfn> provide a method to use
- multiple soundcards as a single device. For example, you can
- aggregate two 8-channel devices so that you can record 16 channels
- into Ardour.
-</p>
-<div class="note">
-<p>
- If you are using a <em>single</em> typical 3rd party
- audio interface (such as those from Apogee, RME, Presonus, and many
- others), <em>or</em> you are using JackPilot or a similar
- application to start JACK, you do not need to worry about this.<br />
- You will need to set up an aggregate device only if either
- of the following conditions are true:
-</p>
-<ul>
- <li>You want to use two entirely separate
- devices <em>and</em> want to start JACK using Ardour.</li>
- <li>You want to use your <dfn>builtin audio device</dfn> <em>and</em>
- want to start JACK using Ardour.</li>
- <li>You want to use more than two entirely separate devices</li>
-</ul>
-</div>
-<p>
- In the case of your builtin audio device, you will need to create
- an aggregate device that combines "Builtin Input" and "Builtin
- Output" into one device.
-</p>
-<p>
- The precise instructions for creating an aggregate device on OS X
- have varied from one released to another.
-</p>
-<dl class="wide-label">
- <dt>OS X 10.5</dt>
- <dd>Please read <a href="http://support.apple.com/kb/HT1215">http://support.apple.com/kb/HT1215</a></dd>
- <dt>OS X 10.6 or later</dt>
- <dd>Please read <a href="http://support.apple.com/kb/HT3956">http://support.apple.com/kb/HT3956</a></dd>
-</dl>
-
-<h2>Linux</h2>
-<p>
- Please see the instructions at <a href="http://jackaudio.org/faq"
- title="http://jackaudio.org/faq">http://jackaudio.org/faq</a>
-</p>
-