Currently a studio event emitter will only look for a rigidbody on its gameobject.
Any complex character, enemy or building will be composed of multiple gameobjects. But only the root object can have a rigidbody, and thus the root object must host all sound event emitters.
This is not good practice, but there are no alternatives, except modifying the source code of StudioEventEmitter or manually setting the 3d settings after any call to StudioEventEmitter, all StudioEventEmitters must be on the root object, or lose any velocity/relative-velocity information.
A simple alternative would be to add a rigidbody override. Manually setting the rb of a listener would be more efficient and more adaptable than any other solution.