DigiDesign Pro Tools 8.0 Reference Manual page 692

material equally. However, when working with
sample-based (non-Elastic) audio on tick-based
tracks, tempo changes affect the start location of
audio regions, but not their duration.
Since the length of each sample-based audio re-
gion in a track is unaffected by changes in
tempo, existing automation data is not aligned
with the audio after a tempo change is made to
a tick-based audio track.
When tempo changes on a tick-based audio track...
Tempo at 120 bpm
No Elastic Audio
Tick-based
...automation gets out of sync with audio.
Tempo at 146 bpm
Tempo changes applied to (non-Elastic) audio regions
Minimizing Automation Drift
In general, automation drift is more pro-
nounced with larger sample-based audio re-
gions. By creating many small regions, the ef-
fects of automation drift can be minimized,
because the start points of each subsequent re-
gion changes as the tempo changes. When
tempo is decreased, automation expands. When
tempo is increased, automation contracts.
674 Pro Tools Reference Guide
Using many smaller regions...
...keeps audio aligned with automation changes.
Tempo changes applied to small sample-based regions
on a tick-based track
To break an audio region into smaller re-
gions, use Beat Detective. For more informa-
tion, see Chapter 28, "Beat Detective."
You can also separate regions at transients
or based on the current grid resolution. For
more information, see "Separate Com-
mands" on page 496
Tempo Changes and Tick-Based
Elastic Audio Tracks
Regions on tick-based, Elastic Audio-enabled
tracks apply Time Compression and Expansion
(TCE) based on tempo changes. For simple
tempo changes, regions on tick-based Elastic Au-
dio-enabled tracks automatically conform to
match the new tempo. Tempo changes do not
affect sample-based, Elastic Audio-enabled
tracks. In Figure 41 below, the first two-bar re-
gion is at its native tempo of 120 bpm. The sec-
ond two-bar region has been conformed to the
tempo change of 100 bpm. Since the second re-