Figure while I'm revisting this thread I'll post a few photos of my most recent outdoor variation on these themes, from the Wanee festival earlier this spring at the Spirit of the Swannee in Live Oak, FL. as I'd meant to post these here a few months back.
This year at Wanee I broke out my old hard Nerf-ball DIY APE's (Acoustic Pressure Equalizers as DPA calls them) which I was using years ago on my 4-omni rigs discussed at length earlier in this thread. In these photos they are the round black balls on the far ends of the thin telescopic antennas and have hemispheric foam windscreens pinned to them. The omnis are flush to the ball surface under the apex of the foam hemispheres. Years ago, I originally used those to give the omnis a bit more forward directionality, focus and a presence range boost, partly to help compensate for less spacing than I would have preferred. This time I have sufficient spacing between the omnis (5' instead of 3') and get all the focus and presence I need from the four near-spaced 4098 supercardioids pointing forward, left, right, and backwards. I now use the left and right facing supercards as the primary Left and Right channels. The wide spaced omnis still provide all important deep bass extension and stereo bass information to the Left and Right main channels, which are qualities unaffected by the sphere attachments.
The intention of using the APE spheres this time is to give the omnis some rearward directionality preference and presence above the bass range, reducing their sensitivity in the mids and highs slightly with respect to pickup of direct sound from in front. That's because, outside of the bass range, I'm now mostly using the omnis for ambience in a 2-channel mix, and as dedicated surround channels for surround playback. A bit less direct sound pickup pickup from in front allows me to use more ambience / surround level. The APEs are probably not giving me the 6-10 dB reduced sensitivity towards the front which I figure would be optimal, but it was easy to implement with what I had on hand. If wondering about their angle in the photo, made apparent by the hemispheric windsceens, their primary rearward axis actually face about 135 degrees and 225 degrees away from the front, which aligns their minimum sensitivity point with dead-ahead since the polars for spherical APEs show a small rear lobe. Plus I'd originally designed them to face +/- 45 degrees forward, so it was easy to just turn them around.
I'd been thinking of using rear-facing subcards in place of the omnis, which would provide about that amount of directionality without compromising bass extension too much or tonal quality of what is picked up from in front, but I don't have any subcards. I've also thought about placing the Naiant X-8S bidirectionals coincident with the 4061 omnis so I could vary the pattern from forward facing through omni to rear-facing how ever I like as in the Schoeps Polar Flex system. That would be the ultimate in terms of control- I could even vary the pattern with frequency (omnidirectional at LF routed to the Left and Right main channels, and rear facing cardioids for ambience and surround channels excluding the front sound) but that would would require two additional recording channels. And both of those options would be too heavy to be able to be supported by the telescopic antennas at a 5' spread anyway.
The other modification was punching holes through my two big Shure windscreens for use on the left and right facing 4098 supercards. That kept the heavy screens supported by and tight to the telescopic antennas, keeping things from flopping around and making setup, breakdown and hauling a bit easier. As you can see from the one photo of the rig setup up low at the front rail, those B.A.Shures are due for replacement anyway, so I didn't feel too bad punching holes through them for this test run. I think I'll make this a permanent feature once I replace the screens.
There was also a certain synchronicity in pulling out the Nerf APEs in that one of the bands playing this year was DSO (they did a mightily fine rendering of Cornell 5/8/77) and the last I'd recorded them was years ago at Langarado out in Big Cypress when Dan Healy was running their sound and I was first experimenting with the APEs. He loved the antenna spaced omnis and signed one of the APE balls for me. I think I blathered about that early in the thread, but it meant a lot to me.
Edit- here's the one Healy signed for me-