This is a set up that has worked well for chamber music in PAH:
Avenson STO-2s about 1 foot apart, 6-8 feet above the stage floor, with the stand pushed right up against the stage. API 512 mic pres are next in line, going into the Apogee Duet set to XLR Line +4 dB. This combination seems to quiet down the Avensons a bit (the API tames highs) and keep PAH's brightness in check. Sounds best with string ensemble, brass ensemble, woodwind ensemble, etc.
The Avensons are warmer-sounding mics than the KM184s. Spaced omni is usually considered a warmer technique than coincident pairs like ORTF and NOS. The APIs are the warmest mic preamps we have… so this is a recipe for attenuating harsh frequencies. The spaced omni (or A/B cardioid) technique offers a slightly "more blended than reality" quality. This sometimes makes it preferable for ensembles. Notably, this set up may not work as well for solo instrument with piano accompaniment. At least, not with quieter instruments/voices (the piano might overpower in such a situation). In addition, a solo instrument is much more localized on the stage. Considering the "blending" of the A/B spaced technique, it may prove difficult to retain a strongly centered image for the solo instrument.
