Anyone mounted on the ceiling?I can confirm that, we ABed at Jazzhead's place, he also has smaller wings, 1 each on the floor in front of the speaker raised up at a slight angle towards the speaker - very effective.
At Flyer's place, I ABed 4 wings behind the listener, and at Elberoth's I ABed 2 at first reflection points. They always worked creating spaciousness, focus, and soundstage
Will start with three, yes diffusion can be used on the floor, just as can be used on the ceiling. Lot easier to put on floor though I guess.
Before I get accosted by the retentive masses, I know these most likely scatter rather than diffuse strictly speaking. All I want is better focus and sense of space. Already use wooden devices that scatter behind my rack.