Specifications

Audio Plug-Ins Guide192
A small room may have only a fraction of a sec-
ond before the first reflections, whereas large
spaces may take much longer. The elapsed time
of the early reflections defines the perceived size
of the room from the point of view of a listener.
TL Space offers various controls over early re-
flection parameters.
The time delay between the direct sound and the
first reflection is usually known as Pre Delay. TL
Space lets you adjust Pre Delay. Increasing the
Pre Delay will often change the perceived clarity
of audio such as vocals.
Reflections continue as the audio reaches other
surfaces in a space, and they create more reflec-
tions as the sound waves intermingle with one
another, becoming denser and changing in char-
acter depending on the properties of the room.
As the room absorbs the energy of the sound
waves, the reverb gradually dies away. This is
known as the reverb tail and may last anywhere
up to a minute in the very largest of spaces.
The reverb tail will often vary at different fre-
quencies depending on the space. Cavernous
spaces often produce a booming, bassy reverb
whereas other spaces may have reverb tails
which taper off to primarily high frequencies.
TL Space allows for equalization of the frequen-
cies of the reverb tail in order to adjust the tonal
characteristics of the reverb sound.
A reverb tail is often described by the time it
takes for the sound pressure level of the reverb
to decay 60 decibels below the direct sound and
is known as RT60. Overall, TL Space allows de-
cay to be adjusted as required. For surround
processing, decay can be adjusted for individual
channel groups.
TL Space Convolution Reverb
Convolution reverb goes beyond traditional an-
alog and synthetic digital reverb techniques to
directly model the reverb response of an actual
reverb space. First, an impulse response (IR) is
taken of an actual physical space or a traditional
reverb unit. An IR can be captured in mono, ste-
reo, surround, or any combination. The IR, as
displayed by TL Space, clearly shows the early
reflections and the long decay of the reverb tail.
TL Space uses a set of mathematical functions to
convolve an audio signal with the IR, creating a
reverb effect directly modeled on the sampled
reverb space. By using non-reverb impulse re-
sponses, TL Space expands from reverb applica-
tions to a general sound design tool useful for
many types of audio processing.
The downside of traditional software based con-
volution reverbs is the heavy CPU processing re-
quirement. This has often resulted in earlier
convolution reverbs with unacceptable latency.
Many early software convolution reverbs did not
offer adequate control over traditional reverb
parameters such as Pre Delay, EQ, or decay time.
TL Space redefines reverb processing in
Pro Tools by offering zero and low latency con-
volution with the full set of controls provided by
traditional synthetic reverbs.
Impulse Response sample