I have never seen a real advantage to LF horns - and the disadvantages of internal resonances from the folds, etc. is obvious. Please give a rference to the "tests" that prove your position.

Of course your statement is rather general and ill defined. Do you mean "outperform" in general or that a specific driver in a horn will outperform the same driver direct radiating. Because to the first point, I don't agree at all. I can always find a bigger driver in the same size enclosure as the horn that will produce as much SPL and low distortion as another driver with a horn. To the second point, an Acoustic Lever will always outperform a horn in this regard - higher SPL, lower distortion for a given driver in a given enclosure volume - so give me the lever, not the horn.