Here's an FOB tape I made with my mk21s. Maybe 15' from the stage, approx 5' high. I was
just inside the PA and the bassist's monitor was facing away from the mic so I didn't capture a lot of the bassist, rest assured that is NOT a shortcoming of the capsule but rather location. Mics were oriented in wide ORTF, 27 cm/110 degrees.
https://archive.org/details/ns2018-06-14.flac24Soundstage is *particularly* impressive. When the image shifts, that's because the PA was adjusted on-the-fly by the sound guy and the image is moving from where the musician is on-stage and shifting towards a respective PA speaker.
Edit: Re: the mk21 vs mk22, it's a matter of preference and both are great capsules. I think of the 21 more as an ensemble mic designed to be used as a stereo pair as omnis you can aim, and the 22 more as a slightly less directional cardioid. I would say one is more suited than the other to certain tasks, but I also feel I can make tapes just as well as those using 22s, with my 21s. The 21 has a more aggressive top end to my ear while the mk22 is softer and rounder, though it's not to say either is too hard or too soft. Spin enough tapes of both the 21 and 22 (they're all over relisten.net or archive, and *definitely* on eTree) and it won't be a direct mapping of how you'll use them but it'll give you a rough idea of the characteristic of the cap, and which one you might be more inclined to use.
Here's an FOB tape I made with the mk21 in NOS of Phish at the Gorge last summer:
http://bt.etree.org/details.php?torrentId=600535And here's an FOB Noah made with the mk22 in NOS of Phish at Dick's last summer:
http://bt.etree.org/details.php?torrentId=602095Notably, aside from 60v vs 48v on our Naiant PFAs, Noah's and my signal chains are identical. So aside from the positioning and venues of these tapes, pretty much everything else about these signal chains are identical. I will say that for *my* FOB tape, I think I was too close and captured more of the on-stage monitors than I did of the PA and thus the image sometimes collapses on the center fill, but otherwise I think soundstage is pretty darned good. If you want an idea of the bass response the mk21s are capable, I point you to this tape:
http://bt.etree.org/details.php?torrentId=603572