Planning to do some ambiant recordings soon, and with the 2 NT5's I have coming in I'll grab a stereo bar for the obvious and easy spaced pair. Suppose I wanted to do an x/y - the bar's blurb claim it can but the mics obviously won't be on top of eachother, as they are fixed to the rail. How will this affect the final results? Will I run into phase issues?
I've used a stereo bar for X/Y before. Clearly the mics can't both be at the exact same angle of elevation and have coincident capsules; but you can adjust the angles slightly and make the capsules coincide. I do have a slight anti-audiophile bias, but i sincerely doubt that the difference in angle of elevation between the mics will be an audible one.
There are accessories just as this little screw, to do exactly that, raise one of the mics slighly so that you keep the same angle. But yeah, like Roger said, i wouldn't sweat it.
There's a debate that occurs every once in a while about the merits of X/Y vs. ORTF when working with cardioid pattern mics. The thrust of the argument is that ORTF is a better choice when using cardioid, but hyper-cardioid works great with X/Y. Really, it's nothing more than a matter of personal preference. Those two setups can provide a wider stereo-image (especially for ambiences).
If you've got the stereo bar, why not give ORTF a shot and see how you like it? It could be just the thing, as you want the capsules at the same height in that configuration anyways.