10.6

298Logic Pro Effects
Use the Space Designer Definition parameter
The Definition parameter emulates the diffusion of natural reverb patterns when in
Synthesized IR mode.
Natural reverbs contain most of their spatial information in the first few milliseconds.
Toward the end of the reverb, the pattern of reflections—signals bouncing off walls,
and so on—becomes more diffuse. In other words, the reflected signals become quieter
and increasingly nondirectional, containing far less spatial information. To emulate this
phenomenon, use the full impulse response resolution only at the onset of the reverb,
then use a reduced impulse response resolution toward the end of the reverb.
• In Logic Pro, vertically drag the Definition field at the top of the global parameters
section to set the crossover point—where the switch to the reduced impulse
response resolution occurs.
The Definition field is shown as a percentage, where 100% is equal to the length of the
full resolution impulse response.
Use the Space Designer predelay feature
Predelay is the amount of time that elapses between the original signal and the initial
early reflections of the reverberation. For a room of any given size and shape, predelay
is determined by the distance between the listener and the walls, ceiling, and floor. Space
Designer lets you adjust this parameter beyond the range that would be considered natural.
• In Logic Pro, rotate the Predealy knob to set a suitable predelay time.
The ideal predelay setting for different sounds depends on the properties of—or more
accurately, the envelope of—the original signal. Percussive signals generally require
shorter predelays than signals where the attack fades in gradually, such as strings.
A good rule of thumb is to use the longest predelay possible before undesirable side
effects, such as an audible echo, begin to materialize.
In practice, an extremely short predelay tends to make it difficult to pinpoint the position of
the signal source. It can also color the sound of the original signal. On the other hand, an
excessively long predelay can be perceived as an unnatural echo. It can also divorce the
original signal from its early reflections, leaving an audible gap between the original and
reverb signals.
These guidelines are intended to help you design realistic-sounding spaces that are
suitable for various signals. If you want to create unnatural sound stages or otherworldly
reverbs and echoes, experiment with the Predelay parameter.
Change the impulse response start point
The IR Offset parameter affords a number of options that can be quite creative,
particularly when combined with the Reverse function. See Logic Pro
Space Designer
global parameters.
Note: The IR Offset parameter is unnecessary in Synthesized IR mode, because the Length
parameter provides identical functionality.
• In Logic Pro, vertically drag the IR Offset field at the top of the global parameters
section to shift the playback start point of the impulse response.
This effectively cuts off the beginning of the impulse response, which can be useful for
eliminating level peaks at the start of the sample.