Effects Reference

130 Chapter 11 Convolution Reverb: Space Designer
Predelay
Predelay is the amount of time that elapses between the original signal and the initial
early reflections from the reverb generated by Space Designer.
For a room of any given size and shape, predelay determines the distance between the
listener and the walls, ceiling, and floor. Of course, Space Designer allows you to adjust
this parameter separately from, and over a greater range than what is considered natural
for predelay. In practice, too short a predelay tends to make it difficult to pinpoint the
position of the signal. It can also color the sound of the original signal.
On the other hand, too long a 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 signals. The ideal predelay setting to create a realistic space 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. A good rule of thumb is to use the longest predelay possible before
undesirable side effects, such as an audible echo, begin materializing.
Obviously, these guidelines are designed to help you design realistic sounding spaces.
If you want to create unnatural soundscapes using Space Designer, experiment with
the Predelay parameter to create otherworldly reverbs and echoes.
IR Start
The IR Start parameter enables you to shift the playback point into the impulse
response, which will effectively cut off the beginning of the impulse response.
For example, the IR Start parameter can be used to eliminate any peaks at the
beginning of the impulse response sample. It also offers a number of creative options,
such as its use when combined with the Reverse function (see “Button Bar” on
page 131).
Note: The IR Start parameter is not available in Synthesized IR mode. In the Synthesized
IR mode this parameter is not required as, by design, the Length parameter provides
identical functionality.