Specifications
Chapter 2: Pro Tools Concepts 21
Tick-Based Audio and MIDI
Tick-based audio is fixed to a Bars|Beat location,
and moves relative to the sample Timeline when
tempo and meter changes occur. However, MIDI
events and tick-based audio respond differently to
tempo changes with respect to duration. MIDI note
events change length when tempo or meter is ad-
justed, while audio clips do not (unless Elastic Au-
dio is enabled). When Elastic Audio is not enabled
on an audio track, meter and tempo changes affect
only the start point (or sync point) for each audio
clip in a tick-based track. If Elastic Audio is en-
abled on an audio track, tempo changes apply Elas-
tic Audio processing, which changes the duration
of the audio clip.
Elastic Audio
Elastic Audio provides real-time and non-real-time
(rendered) Time Compression and Expansion
(TCE) of audio. Tick-based Elastic Audio tracks
actually change the location of samples according
to changes in tempo. The audio stretches or com-
presses to match changes in tempo. Elastic Audio
also provides high-quality non-real-time clip-
based pitch shifting.
Pro Tools Elastic Audio uses exceptionally high-
quality transient detection algorithms, beat and
tempo analysis, and real-time or rendered TCE
processing algorithms. Elastic Audio lets you
quickly and easily tempo conform and beat match
audio to the session’s Tempo ruler. It also provides
an unprecedented degree of control over transient
detection and TCE processing on an event-by-
event basis.
With Elastic Audio, Pro Tools analyzes entire au-
dio files for transient “events.” For example, an
event can be a drum hit, a sung note, or chord
played by a guitar. These detected events can then
serve as control points for “warping” the audio.
Pro Tools can warp (TCE) audio events automati-
cally, such as when automatically conforming au-
dio to the session tempo or quantizing audio
events, or you can warp audio manually using the
standard editing tools with the audio track set to
Warp view.
Elastic Audio is useful in several common work-
flows: working with loops, correcting perfor-
mances, remixing, beat and pitch matching, and
sound design and special effects.
System Resources
Track count, plug-in processing, signal path and
routing options, and voice availability are ulti-
mately limited by the combined resources avail-
able from the host computer and from your
Pro Tools hardware.
Pro Tools provides several ways to manage and
conserve resources to maximize the performance
of your system. As you begin working with
Pro Tools sessions and tracks, you can take advan-
tage of the following features to extend the effec-
tiveness of your available DSP and other re-
sources:
Pro Tools lets you adjust the performance of
your system by changing system settings that af-
fect its capacity for processing, playback, and re-
cording. See “Configuring Pro Tools System
Settings” on page 64.
In order to free up needed DSP resources,
Pro Tools allows for certain items (such as tracks
and inserts) to be manually made inactive. Inactive
elements are viewable, editable, and retained