Yeah, what both of those guys said!
Get a tall stand.
Numerous ways to go about recording large festivals and how you choose to do it will be a primary influence on the most appropriate choice of mics. Might record back by the soundboard, might record up in the sweet spot center, might record DFC at the rail in front of a fill speaker, to one side in front of a PA stack, far back behind a delay tower.. That said, generally I'm in full agreement on using mk22 as a straight 2-ch stereo pair. It's an excellent natural sounding open pattern with good bass translation and reduced susceptibility to wind that is likely to shine in that application, and it shouldn't be a problem running them in a properly angled and spaced config at an open-taping festival. Assuming you will be recording from somewhere farther back near the sound board / tapers section, use a tall stand that is well secured against toppling. Getting the mics up high will do a far better job of managing audience chatter than shifting to a more directional pattern used at a low height. Using sufficient spacing as suggested by Improved PAS at that distance from the stage will also help make what audience noise you do pick up less distracting. In contrast, highly directional mics on a low stand will attenuate chatter behind the recording position, but will not attenuate pick up of all the audience forward of the recording position. The best option for managing audience chatter is to get the mics as far away from the chattering audience as possible, and the easiest way to do that is to raise them up high. Alternate options to getting them up high above the audience include using directional mics placed between the audience and the sound source, say DFC front rail in line with a fill speaker, stack taping from over to one side, directly behind a repeater in back, etc., and/or positioning the rig close enough to the source that it's significantly louder than the audience.
Outdoors allows for running patterns that are more open with less of the problems inherent to running the same indoors, and generally pays off nicely. I'd not hesitate to run the 22's..
But then I'd run more than a single pair. I'd run the open-pattern pair spaced more widely than normal which will provide a very natural, open, deep, "sounds like I'm there" foundation and a somewhat diffuse pickup of audience reaction, along with a coincident or narrow-spaced highly-directional pair that won't sound nearly as big, open and natural yet will provide maximum forward sensitivity for clear and more up front sounding pickup of the PA and stage sound from a distance, as a way of combining the best of both. In that scenario, the more open-pattern pair would be the
must have foundational part of the recording for me, and the more more directional pair would provide a
nice to include additional improvement to it.
[edit- Both mk22 and mk41 like David says 
] But if I was limited to running a single pair and recording from the sound board area, I'd run the 22's in a
Improved PAS configuration on a tall stand.
Topic: Wich mics for open air show? (Read 5435 times)