Using a thread adapter to gain some extra height between the mics is the usual solution,
but in my opinion entirely pointless.
If you work out the amount of angular
error at the capsule if you don't bother with a stand-off you'll see it is tiny --
typically less than 7 degrees.
Worst case I could come up with was using a pair
of Neumann KM184s in XY, since these are the shortest and stubbiest mics I know of that
you might want to rig as XY or ORTF and so cross their bodies over.
scale diagram shows the error is only +/-7 degrees. With longer mics the error will be
This kind of vertical angular error is
utterly insignificant in comparison to the huge horizontal angle over which you expect the
mic to capture the stereo sound field.
So my advice: use a stand adapter to
gain height for one mic if you prefer the look of neatly parallel mics, but you won't hear
the difference and I never bother!
Technical Editor, Sound On Sound