Checkout the 3D project in the LowLevel API examples (api/lowlevel/examples/3d.cpp).
You don’t need to add a panner to the 3D sound because the system will set a matrix on the channel fader or channelgroup fader, and use its own code in update to do the 3d calculations.
This allows you to use event->set3DMinMaxDistance() and channel->set3DAttributes.