Apple Soundtrack - Manual (Page 133)

Chapter 8 Working with Audio Effects 133
Simple reverb effects provide parameters for the decay time or reverb time, which let
you set how long the reverb lasts before dying away, and the mix or level, which you
use to set the ratio of the effected signal (called the wet signal) to the original (the dry
signal). More sophisticated reverbs can include the following parameters:
 Room type: Lets you set the type of space the reverb will simulate: a small or large
room, a hall, or another type of acoustic space.
 Predelay time: In an acoustic space, there is a short period of silence between a
sound and the time when the initial echoes of the reverb begin. Different spaces
have different amounts of predelay, which helps “tell” our ears how large the space is.
Longer predelay settings also help separate the original (dry) signal from the effected
(wet) signal, making it sound clearer and sometimes larger.
 Early reflections: The first echoes to arrive from the surrounding surfaces in a space
are determined by the size and shape of the space, and “tell” our ears what type of
space it is.
 Diffusion: Lets you set the number of the echoes in the reverb. Hall reverbs typically
have low diffusion settings, while plate reverbs typically have high diffusion settings.
 High-frequency and low-frequency reverb time: These parameters let you specify the
decay of higher and lower frequencies separately. Different surfaces, such as wood
floors and concrete walls, absorb high and low frequencies at different rates, and
these parameters let you simulate the sound of different environments more closely.
 Reverb envelope: Lets you control how much the volume of the reverb changes over
time. In natural acoustic situations, the reverb echoes decay gradually over time. You
can re-create this gradual decay, or gate the reverb so that it cuts off more abruptly.
Miscellaneous Effects
Miscellaneous effects don’t fall into any of the other categories. They include denoising
effects, pitch shifting effects, stereo enhancers, bass enhancers, and effects used to
transform the sound of vocals. Each effect gives you a different way to modify the
audio, and includes a unique set of parameters.