Maybe more info than you want!..
M/S using a fig-8 mid decodes to X/Y Blumlein.
A Blumlein pair is fully omnidirectional in the horizontal plain, with no forward sensitivity bias. It's just as sensitive to sound arriving from the rear and sides as it its to sound arriving from the front. Think of it like an omni in that sense. Because of that it typically works best in a good sounding room from a recording position relatively close to the source, in order to avoid having the recording dominated by hall reverberence. From a "taper section" type distance I'd use a cardioid or supercardioid Mid, as that will provide more forward sensitivity bias which is likely needed from a recording position that is further back.
Generally, a fig-8 Mid works in the same way any other M/S arrangement. The one thing that is unique about it is that because both Side and Mid are fig-8 patterns, only the inclusive angle between the virtual X/Y pair changes as you alter the Mid/Side ratio. The pattern of the virtual crossed pair will always consist of a pair of virtual fig-8's. This is different than any other Mid pattern where the virtual pattern morphs between whatever the Mid pattern is (at 100% Mid, mono) and 180° angled fig-8's (at 100% Side).
At a 50/50 ratio, a Mid/Side pair using a cardioid Mid provides the most forward bias, decoding to something like a virtual pair of 90° crossed supercardioids. A supercardioid Mid at 50/50 ratio will decode to something with a bit less forward bias, more like a pair of 90° crossed hypercardioids, and will sound more Blumlein-like. That little bit of forward bias might be just enough to help with needed clarity if the recording position isn't really close enough or the room good sound enough for Blumlein to shine.
To complicate this a bit, from a distance, the apparent width of the stage and PA is going to be narrow, so it might actually work best to use a supercardioid Mid to get the needed clarity, along with a Mid/Side ratio of less than 50/50, which will narrow the angle between the virtual pair and thus increase forward bias at the expense of some stereo width, somewhat compensated for by the change from cardioid to supercardioid Mid.
In general I prefer coincident pair stereo from closer recording positions, where its possible to get sufficient angle between microphones without them being pointed overly far off axis, and configurations that rely more on spacing along with less angle between microphones, from recording positions that are further away, unless doing something like combining both approaches in an array.
Topic: M/S with two Figure 8's (Read 1356 times)