Specifications

Chapter 11: TL Space TDM and TL Space Native 83
IR Library
• A wide variety of both real and synthetic
reverb spaces and effects
• Mono, stereo, and surround formats
• All reverb impulse responses stored in WAV
file format
Reverb and Convolution
Reverb Concepts
Reverberation is an essential aspect of the sound
character of any space in the real world. Every
room has a unique reverb sound, and the quali-
ties of a reverb can make the difference between
an ordinary and an outstanding recording. The
same reverb principles responsible for the sound
of a majestic, soaring symphony in a concert
hall also produce the booming, unintelligible
PA system at a train station. Recordings of audio
in the studio context have traditionally been
captured with a minimum of real reverb, and
engineers have sought to create artificial reverbs
to give dry recorded material additional dimen-
sion and realism.
The first analog reverbs were created using the
‘echo chamber’ method, which is comprised of
a speaker and microphone pair in a quiet, closed
space with hard surfaces, often a tiled or con-
crete room built in the basement of a recording
studio. Chamber reverbs offered a realistic, com-
plex reverb sound but provided very little con-
trol over the reverb, as well as requiring a large
dedicated room.
Plate reverbs were introduced by EMT in the
1950s. Plate reverbs provide a dense reverb
sound with more control over the reverb charac-
teristics. Although bulky by modern standards,
plate reverb units did not require the space
needed by a chamber reverb. Plate reverbs func-
tion by attaching an electrical transducer to the
center of a thin plate of sheet metal suspended
by springs inside a soundproof enclosure. An ad-
justable damping plate allows control of the re-
verb decay time and piezoelectric pickups at-
tached to the plate provide the return reverb
signal to the console. An alternative and less ex-
pensive analog reverb system is the spring re-
verb, most commonly seen in guitar amplifiers
beginning in the 1960s. Similar to the plate re-
verb in operation, the spring reverb uses a trans-
ducer to feed the signal into a coiled steel spring
and create vibrations. These are then captured
via a pickup and fed back into an amplifier.
Since the advent of digital audio technology in
the 1980s, artificial reverberation has been cre-
ated primarily by digital algorithms that crudely
mimic the physics of natural reverb spaces by
using multiple delay lines with feedBack. Digital
“synthetic” reverb units offer a new level of re-
alism and control unavailable with older analog
reverb systems, but still fall short of the actual
reverb created by a real space.
Components of Reverb
Reverberation sound in a normal space usually
has several components. For example, the
sound of a single hand clap in a large cathedral
will have the following distinct parts.Initially,
the direct sound of the hand clap is heard first,
as it travels from the hand directly to the ear
which is the shortest path. After the direct
sound, the first component of reverb heard by a
listener is reflected sound from the walls, floor
and ceiling of the cathedral. The timing of each
reflection will vary on the size of the room, but
they will always arrive after the direct sound. For
example, the reflection from the floor will typi-
cally occur first, followed typically by the ceiling
and the walls. The initial reflections are known
as early reflections, and are a function of the re-
flective surfaces, the position of the audio
source and the relative location of the listener.