Operation Manual

6.70 Reverberator 130
6.70 Reverberator
The Reverberator module is used to recreate the effect of the
reflexion of sound on the walls of a room or a hall. These reflex-
ions add spaciousness to the sound and make it warmer, deeper,
and more “real”. This makes sense as we always listen to instru-
ments in a room and thus with a room effect. This module has
two inputs, the left and right source signals and its two outputs
are these signals as they would be heard in a given room.
Impulse Response of a Room
The best way to evaluate the response of a room is to clap hands
and to listen to the resulting sound. Figure 74 shows the amplitude of the impulse response of a
room versus time. The first part of the response is the clap itself, the direct sound, while the remain-
ing of the response is the effect of the room which can itself be divided in two parts. Following the
direct sound, one can observe a certain amount of echoes which gradually become closer and closer
until they can not be distinguished anymore and can be assimilated to an exponentially decaying
signal. The first part of the room response is called the early reflexion while the second is called the
late reverberation. The total duration of the room response is called the reverberation time (TR).
Direct Sound Room Response
Early reflexions Late Reverberation
dB
Reverberation Time (TR)
Amp
Time
Figure 74: Impulse response of a room.
Adjusting the room effect
The size of a room strongly affects the reverberation effect. The size button is used to choose this
size from small (1) to large hall (4). The duration of the reverberation time (TR) depends on both
the size of the room and the absorption of the walls, which can be adjusted with the decay knob. In
a real room the reverberation time is not constant over the whole frequency range. As the walls are