Apple Logic Pro 9 - Manual (Page 247)

Tip: The Freeze function also works with DSP hardware such as the PowerCore, LiquidMix,
Duende, and UAD devices. This compatibility allows you to combine Logic Pro instruments
and effects with those provided by the DSP hardware, even if the processing capacity of
your computer, the DSP hardware, or both, are exceeded.
The Freeze function always bounces the complete channel signal. If you are using more
than one track for the same audio or instrument channel in the Arrange area, then all
(sub)tracks of this channel are frozen, and cannot be edited independently. In other words,
it is the channel strip that is frozen, not the track.
Knowing When to Freeze a Track
In real-world situations, Freeze allows you to:
• Use extra effect plug-ins or software instruments in additional audio or instrument
tracks, which would normally be impossible as it would exceed the CPU-processing
limits of your computer.
• Play back projects created on computers with greater CPU power.
Freeze is designed to circumvent very CPU-intensive processes, which are generally
outlined as follows (from highest to lowest demand):
• Software instruments with a complex voice architecture
• Plug-ins with a complex structure (reverbs, filter banks, or FFT-based effects)
• Software instruments with a simple voice architecture
• Software sampler with active filter
• Software sampler with inactive filter
• Plug-ins with a simple structure
If your computer is able to calculate all active processes in real time, it’s unnecessary to
freeze tracks.
Freeze is recommended whenever your system’s processing power runs short and one,
or multiple, existing tracks with CPU-intensive software instrument or effect plug-ins are
in a finalized state, or at least seem to require no further changes for the time being—in
other words, a close-to-final mix.
As long as a track is frozen, its CPU usage is reduced to that of a high-resolution audio
playback track with no effect plug-ins inserted, regardless of the number, or processing
demands, of the plug-ins that were originally used on the track.
Freezing a Track
It’s easy to freeze a track, using the Freeze button in the track header and the Freeze
mode parameter in the Inspector’s Track Parameter box.
247 Chapter 9 Working with Tracks