If, by the same thing, you mean "nothing" - because the claim is bogus even among the Sennheisers - the world is your oyster.
In the world of loudspeakers, you can position sats at the back of the room, but unless the recording is quadrophonic, you're not introducing new information. You're just duplicating left and right channels. This may stretch the soundstage, but it also affects the imaging.
On the other hand, it's possible to use the rear or "surround" sats to create a psychoacoustic effect. I do that with mine. I don't want my rear speakers to ruin the soundstage so I set them low, almost imperceptibly so. At certain spikes, I'll hear a trace echo, which my mind interprets as additional space. But otherwise, the sound is coming from the front of the room, balanced between left and right to a place hovering, for the most part, in the center.
When you get to headphones, one of the greatest challenges is to create headroom, a sense of spaciousness, when the drivers are obviously aligned right next to each ear. As most headphones only contain a single driver, there's no "surround sound" involved. Circumaural cushions are sometimes marketed as "surround sound" because the cushions surround the ears, but even then, it's puffery at its best. Just because the ear is inside the cushion, that hardly means that sound is being heard behind the ear.
I'd steer clear of any claims to "surround sound." You will certainly want the effect of "soundstage," but understand that it's a psychoacoustic effect.
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