Issue with Ak Ambient attenuation relative to the Ak Listener in Unity5

Question

I have set up a series of objects in a Unity5 project, each with an emitter and a bespoke cone attenuation. These objects surround the Main Camera object which has the Ak Listener component attached to it.

My attenuations are working as desired but only when the object with the emitter is moved relative to the camera/listener. When I move the camera/listener relative to the object/emitter no change to the sound is heard.

Clearly I am doing something wrong. Any advice / requests for clarification are much appreciated.