The foundation of my multichannel rig is essentially the equivalent of what you are asking about: split omnis + a Mid/Side pair in the center.
Although essentially equivalent in some ways, I prefer a Mid/Side pair over X/Y in the center position for a few reasons. The caveat is it requires a figure-8.. or a stereo M/S mic. I've been using the inexpensive Naiant X8 fig-8 for years and it works well as the Side channel. I recommend it to anyone looking for an inexpensive fig-8 to run a Mid/Side pair. However..
Recently I've been playing around with changing the M/S center pair to a short stereo shotgun. I'm liking what I'm hearing. More center focus and clarity of vocals. Same basic M/S advantages in the center as before. Convenient to run a single stereo mic in the middle. Single mic clip. Very easy to orient and confirm good orientation after raising the stand. Easy wind-screening for the single microphone instead of two.
This switched from a M/S pair of supercard + fig-8 (basically equates to X/Y hypers), to the single stereo shotgun (also M/S and pretty much also equates to X/Y hypers).
Previous center pair was miniature DPA 4098 as MID / Naiant X8 as SIDE.
New short stereo shotgun is AT BP4029 (in a single mic clip).
The omnis are miniature DPA 4061, which I've no intent to change (on telescopic TV antennas that extend from about 2' wide up to about 6' wide).
Give me a call to discuss.
Topic: XY Mount for 1st gen Busman Actives...Is Shapeways still my best bet? (Read 663 times)