Soffit mounting is mounting the speaker so the baffle is the size of the wall it is mounted in to.
This helps because low frequencies don't radiate through 360 degrees, and as such dont produce phasing issues to such an extent. It also stops diffraction from the edge of the speaker because theres no edge so nothing to diffract around.
Does that help?
Joe
ok i wasn't aware of the fact that this is called soffit mounting
but this is not possible, just for the fact that i sometimes have to switch the studio and i'm take my ref monitors with me. also i cant build the wall that strong that it wont be resonating. so i stick with the "monitor on the big desk" version