Yes the horn can be wonderfully efficient Brigham, as Herald said but you need the space for it
The photo dug out by Peter must be pretty much what they had set up in the park at Todmorden. There also were "folded horn" designs and I recall some people mounting down ward facing pairs, using the fireplace alcoves, in the sixties. That was the time of brick built or concrete panel corner cabinet as well. I fancied a pair of those but even my [otherwise very tolerant] parents wouldn't have gone for it
When you look at a sketch of a 30's Radio Workshop, they often have an LS just mounted on a large baffle board maybe angled between the top of the door and the ceiling! Apparently one 5' 6" square, would reproduce the whole fr of an 8" spkr. I suspect Murphy was aiming at that, especially with the larger models in the "Baffle" range. In a way "folding" that big baffle into a smaller efficient box shape sums up one half of the search for audio "perfection".
Dave W