The ReverbType class provides methods for
accessing various reverberation settings to be applied to
an audio signal.
Reverberation simulates the reflection of sound off of
the walls, ceiling, and floor of a room. Depending on
the size of the room, and how absorbent or reflective the materials in the
room's surfaces are, the sound might bounce around for a
long time before dying away.
The reverberation parameters provided by ReverbType consist
of the delay time and intensity of early reflections, the delay time and
intensity of late reflections, and an overall decay time.
Early reflections are the initial individual low-order reflections of the
direct signal off the surfaces in the room.
The late Relections are the dense, high-order reflections that characterize
the room's reverberation.
The delay times for the start of these two reflection types give the listener
a sense of the overall size and complexity of the room's shape and contents.
The larger the room, the longer the reflection delay times.
The early and late reflections' intensities define the gain (in decibels) of the reflected
signals as compared to the direct signal. These intensities give the
listener an impression of the absorptive nature of the surfaces and objects
in the room.
The decay time defines how long the reverberation takes to exponentially
decay until it is no longer perceptible ("effective zero").
The larger and less absorbent the surfaces, the longer the decay time.
The set of parameters defined here may not include all aspects of reverberation
as specified by some systems. For example, the Midi Manufacturer's Association
(MMA) has an Interactive Audio Special Interest Group (IASIG), which has a
3-D Working Group that has defined a Level 2 Spec (I3DL2). I3DL2
supports filtering of reverberation and
control of reverb density. These properties are not included in the JavaSound 1.0
definition of a reverb control. In such a case, the implementing system
should either extend the defined reverb control to include additional
parameters, or else interpret the system's additional capabilities in a way that fits
the model described here.
If implementing JavaSound on a I3DL2-compliant device:
- Filtering is disabled (high-frequency attenuations are set to 0.0 dB)
- Density parameters are set to midway between minimum and maximum
The following table shows what parameter values an implementation might use for a
representative set of reverberation settings.
Reverberation Types and Parameters
| Type |
Decay Time (ms) |
Late Intensity (dB) |
Late Delay (ms) |
Early Intensity (dB) |
Early Delay(ms) |
| Cavern |
2250 |
-2.0 |
41.3 |
-1.4 |
10.3 |
| Dungeon |
1600 |
-1.0 |
10.3 |
-0.7 |
2.6 |
| Garage |
900 |
-6.0 |
14.7 |
-4.0 |
3.9 |
| Acoustic Lab |
280 |
-3.0 |
8.0 |
-2.0 |
2.0 |
| Closet |
150 |
-10.0 |
2.5 |
-7.0 |
0.6 |
| 