number of tracks or busses in Ardour. This is a lot like doing some of the
processing with a chain of guitar pedals, then feeding the signal to an Aux In
port on a mixing console or an input port on a multi-effects digital
- pedalboard. The rationale for pre-processing with I/O plugins is that it's a
- more lightweight way to do it as compared to busses.
+ pedalboard.
+</p>
+
+<p>
+ The rationale for pre-processing with I/O plugins is that it's a more
+ lightweight way to do it as compared to busses. Much of that is because busses
+ have automatable parameters such as fader and panner positions, as well as
+ plugins' parameters. Evaluating automation (even when there's none) is
+ expensive in terms of CPU use. However I/O plugins are not automatable, so
+ there's no evaluation happening. As far as Ardour is concerned, they are
+ almost like JACK audio server clients running alongside Ardour.
</p>
<p>