Max 8.1.6 includes a patch I made in collaboration with legendary Stanford audio researcher, John Chowning.
The cool trick is panning the reverb return and making it more directional as the virtual object moves farther away. The technique is perfect for concert halls. Since going to concert halls is paused, perhaps it could be useful in VR or in a museum installation. (If you do that - let me know!).
Download Max and check out "Help > Examples > spatialization > quad-spatializer-folder > quad-spatializer.maxpat"