You can't do it with bgt's built-in sound support. Someone posted a bgt binding for the FMOD library, which does support 3d surround sound. You can find it in the forums.

I am very confused as to why my rotation algorithm screws up at distances.
As for behind/not behind, it might be a coordinate system issue, or there might be a negative sign in the wrong spot somewhere. It's easy to fix once you find it, but the trick is figuring out if it's a coordinate system mismatch or if it's in the position_sound functions themselves. It might also be a clockwise/counterclockwise thing (trig functions assume that positive angles are counterclockwise, but that's in the coordinate system where positive y is up/forward).

A better way to do this might be transformation matrices. I can't for the life of me remember how those work for more than 5 seconds after reading it (I've tried more than once, this *after* the appropriate classes from high school), but there's a decent Wikipedia article on the subject.

Yeah, I've actually been regretting choosing bgt for a while now, because I've had to rewrite a lot, and just write some pretty basic stuff from scratch. It also handles pointers in a silly way, and makes linked lists and things like it incredibly difficult to code, ecause you can't create a class from within itself. I'm learning a lot from this though, so although it is frustrating, I don't mind all that much, and I'm determined to finish at least a concept demo in bgt. I'm beginning to think that game programming might not e something I'm going to get into, but it's hard to say. I'm familiar with the general programming concepts, but some of the game spacific stuff seems a little strange. Back on topic though, I found a pretty detailed post from 2012 that explains how sound panning and such was done in games like this, so I might just write something from scratch. Which will be painful.

You can.

class node {
int value;
node@ next=null;
node() {value=0;}
node(int v) {value=v;}
bool hasNext() {return @next!=null;}
node insertNext(int v) {
node n(v);
@next=n;
return n;
}

}

BGT isn't usin the Java reference system, it is using the C++ references system (similar to AngelScript). Java always use references to handle objects, whereas BGT C++ and AngelScript give objects by copy when giving them as function parameters. Because of that, you have to use kind of pointers, or handles. There is a great difference!

Any object oriented language is able to build linked list, even non object ones (the C language can use linked lists). So, yes, it's just a matter of algorithm design. So Dranelement, as CAE_Jones said, you can build a linked list in about 20 lines of code, like in most other languages. If you think it is impossible, then it is a problem with you, not a BGT language problem

I didn't understand what you said, or you totally misunderstood the object oriented concepts

This is logical you can hava a reference in a class definition, but if you declare an object, you would have a infinite recursive loop. All other languages works like that

I don't think this would change left/right at all. I'm not sure, but I don't think it would affect behind-ness, either. Really, I think all you'd need to do is swap labels/variable names for north and south.
But I'd have to try it both ways to be sure.