Ah, I missed the line that gets you the position. The sound system is expecting all positions to be in the same relative coordinates, so you must get the camera position relative to the root of the scene. The same goes for getting the position of the panda. If you use get_pos with no argument it is just giving you the transform of that node, but you need it to take into consideration any parent nodes that might also have a transform on them.
In C++ I think that would be something like:
LPoint3f pos = camera.get_pos(window->get_render());