Only of single ended driven horn systems. The perfect scenario. Horn loading out of the speaker, and reverse horn loading into the ear. Should cancel out non-linearity of the horns, and require about 100 mw power for 150 db at the listener's ear.
With a very directional pickup combined with what *appears* to be parallel aim, I'd say this is not stereo (i.e. coherent) but in fact, dual mono (like most commercial releases ;-}).