According to the "unofficial owner's guide" (and pictures that Ultrasone made ages ago), they should be worn somewhere between the two extremes you're describing - your ears should be centered in the cups and the headband should be over the top of your head (not at an angle); that produces the best effect IME. I will add that "S-LOGIC Plus" is an improvement IMO (it's basically more holes in the baffle, at least that's what it looks like - I have no idea if you could just get out a drill and MacGyver that onto the 750s (I'm finding inconsistent reports from Ultrasone regarding the 750s having Plus or not, especially between the blue and grey versions, I'm assuming they do not given their age and relationship to the 2500)). But yeah, "sometimes soundstage" would describe them well IME - when playing a videogame with good positional audio, or watching a movie with a good surround mix, it's at times uncanny how well they position things in space. But listening to fairly "flat" music they're relatively ho-hum in staging. They don't artificially widen the material as a lot of other "good soundstage headphones" do (like the K701); yes they're bizarre (it's Ultrasone though).
Agreed that S-Logic works different for everyone. I'm thinking its probably because the slightly forward (and low) placement of the driver makes the sound travel "over" the ear which causes individual ear shapes to have more of an effect on the sound.
Yeah the documentation on the PRO 750 is fuzzy on whether it has S-Logic Plus. Looking at these pics of the older blue 750 compared to the newer black one (which I have), they seem to have identical holes over the driver so I'm thinking its not S-Logic Plus:
EDIT: My bad, those pics aren't of the 750s. See below.
Edited by devhen - 1/17/13 at 10:44am