Apple Logic Pro 8 - Manual (Page 463)

Chapter 19 Quantizing MIDI Events 463
2 Double-click on the region to open the Sample Editor, or select the Sample Editor tab
at the bottom of the Arrange window.
3 Choose Factory > Audio to MIDI Groove Template (default key command: Control-M).
4 Choose the desired settings in the Audio to MIDI Groove Template tab:
 Preset menu: This menu contains various presets for the Audio to MIDI parameters,
which are suited to specific types of audio material. You can use these presets as
starting points for your own processing.
 Granulation (ms): Use Granulation to determine the time span of louder components
in the audio material. Logic Pro uses these peak signals (or transients) to derive
information for velocity points in the groove template. The most useful values are
usually between 50 and 200 milliseconds, depending on the tempo of the audio
material.
 Attack Range (ms): This tells Logic Pro how long the attack phases of the sounds in
the audio material are. As examples of how you might use this parameter; drum and
percussion instruments have short attack times of less than 20 ms, while string
instruments have longer attack phases. The best values for the majority of
instruments are usually between 5 and 40 ms; with most around 20 ms.
 Smooth Release (%): This parameter is specifically designed to process audio material
that contains sounds with a long release or reverb tail. This makes it easier to convert
these sounds into suitable quantization points. The value you choose here should
generally be between 0 and 5%, except when processing passages that contain
sustained notes, distorted guitars, or similar sounds.
 Velocity Threshold: This parameter 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.
 Basis Quantize: This function enables you to add artificial trigger points at positions
where there are no trigger points present. Groove templates created with this
method are suitable in situations where you need more quantization points than are
contained in the audio material. The automatic identification of trigger points in the
audio material is not affected by use of this parameter.