These are used for ambient sounds, and you could also make gravity effects with these. After "special effects volumes"-note there is a value, which tells the number of these special effects areas. (boxes)
After the value there is the default water's attributes. When you make new boxes, increase the number of special effects volumes. Now, let's make a box.
2.3 , 0 , 0 // Offset from center for X-axis. (for both sides: left and right)
0 , 0.5 , 0 // Offset for Y-axis. (above and below center) Look at the picture too.
0 , 0 , 5.4 // Offset for Z-axis (forward and back from center)
-6.3 , 0.5 , 43 // Center point of the box in the world. (Coordinates: x,y,z)
-1 // Gravity multiplier, use negative values for inverted gravity.
250 // Viscosity multiplier. (Viscosity slows the car down, like in water)
0.0 // Car damage per millisecond. [No effect, I guess]
0.0 // Pedestrian damage per millisecond.
-1 // Camera effect index. (-1 and 1 = normal , 0 = water zoom in/out)
1 // Sky colour. (-1 = normal pixelmap , 0 = black)
NONE // Windscreen texture to use. [No effect]
5100 // Sound ID of entry noise. (in data/sound/sound.txt)
5100 // Sound ID of exit noise.
2 // Engine sound index. (2 = water , 1 = normal)
10 // Material index. (?)
SCATTERED // Sound type: scattered / saturated / none. If none, don't write the following lines.
RANDOM // Delay between sounds: random / continuous. If continuous, you can use only one sound.
1 , 5 // Mintime,Maxtime between sounds. (delay in seconds) Delete this line if "delay between sounds" is continuous.
1 // I don't know what this is, but 1 is a good value here for ambient sounds.
3 // Number of sounds. (1 if "delay between sounds" is continuous)
4372 // Sound IDs. (get them from data/sound/sound.txt)
Put very big values to offsets (like 200) to create an ambient sound for whole track. (You can hear it everywhere)