Physical Sounds are used when you want to have a kickable make Impact and Sliding sounds when you hit or slide the object.
Ok, you're going to want to start with an empty (your emitter), and then add a random-sound to the object. All we have to do is add the AlcScript#sound settings that we want for the multiple sounds to the "sounds" list. In most cases we'll want to use "static" sounds (you put the wav in the streaming cache for these). Here is an example of the random sound set up with two sounds--both static:
<Emitter-Object name>: type: randomsound randomsound: sounds: - SomeSound1: sound: file: SomeSoundBlock1 volume: 1.0 buffer: static - SomeSound2: sound: file: SomeSoundBlock2 volume: 1.0 buffer: static
As you can see, the stuff listed under "sounds" is exactly the same structure as with normal emitter settings.
Now that we have our random sound emitter we can start work on the actual physical sounds. :D
Here are the props for your physical object (say a beach-ball):
<Kickable-Object name>: physical: sndgroup: (metal|grass|wood|stone|<int>(advanced users only)) impact: <your random sound emitter name (don't use this var if you don't want any)> slide: <your random sound emitter name (don't use this var if you don't want any)>
NOTE: Do not include the parens "()" in your script for the sndgroup line.
Now, since you most likely don't want your object to make sounds elsewhere while you play with it: you'll need to parent the emitter to the kickable object. To do this; first select the emitter, then select the kickable and press CTRL+P and press ok.
Now you need to add a sndgroup to the collider-ground:
<Ground-Object name>: physical: sndgroup: (metal|grass|wood|stone|<int>(advanced users only))
That's everything. Not that much to this is there? ;)