Specifications

Audio Plug-Ins Guide170
Reverberation Concepts
Digital reverberation processing can simulate
the complex natural reflections and echoes that
occur after a sound has been produced, impart-
ing a sense of space and depth—the signature of
an acoustic environment. When you use a rever-
beration plug-in such as ReVibe, you are artifi-
cially creating a sound space with a specific
acoustic character.
This character can be melded with audio mate-
rial, with the end result being an adjustable mix
of the original dry source and the reverberant
wet signal. You can use reverberation to en-
hance relatively lifeless mono source material
with a stereo acoustic environment that gives
the source audio a perceived weight and depth in
a mix.
Acoustic Environments
When you hear live sound in an acoustic envi-
ronment, you generally hear much more than
just the direct sound from the source. In fact,
sound in an anechoic chamber, devoid of an
acoustic space’s character, can sound harsh and
unnatural.
Each real-world acoustical environment, from a
closet to a cathedral, has its own unique acous-
tical character or sonic signature. When the re-
flections and reverberation produced by a space
combine with the source sound, the space is said
to be excited by the source. Depending on the
acoustic environment, this could produce the
warm sonic characteristics associated with re-
verberation, or it could produce echoes or other
unusual sonic characteristics.
Reverb Character
Reverb character depends on many factors in-
cluding the shape of the space, the reflectivity of
the construction material, the proximity of re-
flective elements to the sound source, and the
position of the listener.
Reflected Sound
In a typical concert hall, sound reaches the lis-
tener shortly after it is produced. The original
direct sound is followed by reflections from the
ceiling or walls. These discrete reflections,
which usually arrive within 100 milliseconds of
the direct sound, are called early reflections. The
subsequent, and more diffuse reflections, are
called the reverb tail. The delay time between
the arrival of the direct sound and the beginning
of the reflected sounds is called the pre-delay.
The loudness and panning of early reflections
combined with the length of the pre-delay can
contribute to the perception of size of an acous-
tical space.
ReVibe also uses Room Coloration to accurately
model acoustic spaces and effects. Room Color-
ation is a complex filter process, similar to EQ,
that models the frequency shape of each room or
effect.
ReVibe provides control over these reverb ele-
ments so that extremely natural-sounding re-
verb effects can be created and applied in the
Pro Tools mix environment.
ReVibe can also be used to produce reverb char-
acteristics that do not exist in nature. There are
no rules that you need to follow to produce in-
teresting treatments. Experimentation can often
produce striking results.