Apple Logic Pro 9 - Manual (Page 589)

• Velocity Threshold: Sets the threshold level. All signals that fall below this value are
ignored. In most cases, you should choose a value of 1, except when processing very
dense, loud material with soft background noises.
• Minimum Quality: You can choose between normal and high-quality processing:
• Normal: Is more tolerant of audio trigger points that aren’t perfectly in tune, but it
can generate wrong notes.
• High: Accepts and uses only audio trigger points of a clearly identifiable pitch.
Indistinct trigger points are replaced by notes with a pitch of C3 and MIDI channel
3. These are labeled as an “undetected mark.”
When analyzing audio material that contains clearly identifiable pitches, you will find
that good results can be obtained using either setting.
• Time Correction: Compensates for any time delays that may occur when external
samplers or synthesizers are triggered by MIDI notes. These time delays are sometimes
very noticeable, particularly if the connected device is playing a MIDI region that was
generated by the “Audio to Score” function alongside the original audio material. You
should be able to compensate for this effect by using settings between −20 ms and
0 ms.
Using the Sample Editor’s Quantize Engine
You can use the Quantize Engine to quantize an audio recording, using a dynamic time
compression or expansion algorithm.
The function is similar to using the Groove Machine, except that the quantize template
can reflect values other than just 1/8-note or 1/16-note swing grooves. Even user-defined
MIDI grooves can be used.
Opening the Sample Editor’s Quantize Engine
You need to select an area within an audio file before you can open the Quantize Engine.
To use the Quantize Engine on an audio region
1 Select the area of the audio region in the Sample Editor that you want to process through
the Quantize Engine.
589 Chapter 17 Editing Audio in the Sample Editor