Apple Logic Pro 7 - Manual (Page 183)

Chapter 4 Audio in the Arrange Window 183
The Region Anchor
The Anchor is an Audio Region’s temporal reference point. When you move an Audio
Region, it’s not the start point that is displayed in the help tag (as with MIDI Regions)—
it’s the Anchor point.
As an example, to guarantee perfect synchronization between a one-bar drum loop
and your MIDI Regions, the Anchor must be assigned to a well-defined musical point. If
the loop begins with a significant level peak (say a kick drum beat), set the Anchor to
the point where the volume of that beat is at its precise peak.
Any changes made to the position of the Anchor in the Audio window will directly
affect the corresponding Region in the Arrange window. The position of the audio will
shift in relation to Logic’s time axis, while the Anchor remains tied to the same bar
value, and is marked by a dotted line.
MIDI and Audio Regions compared
The following overview sums up the main differences between Audio and MIDI
Regions. There are some notes at the bottom of the table to clarify the most important
points.
Feature
MIDI
Regions
Audio Regions
Composed of discrete data Yes No, because Regions are just references to
parts of audio files
Can be given names Yes Yes
Loop Region parameter available Yes Yes
Quantize Region parameter available Yes No, but but the position of Regions themselves
can be quantized, using the Event List display
on the Arrange level. You can use the Quantize
Engine to quantize audio files destructively.
Transpose Region parameter available Yes No, but you can use the Time Machine and
Pitch Shifting functions. Apple Loops can be
transposed.
Velocity Region parameter available Yes No
Dynamics Region parameter available Yes No
Gate Time Region parameter available Yes No
Delay Region parameter available Yes Yes