Is blumlein a possibility with a second unit?
Potentially, using just the Side channel of two stereo units, one laid atop the other and turned 90 degrees. Not sure how well that will work in practice for a few reasons:
1) Side channel doesn't use multiple MEMS in parallel to reduce noise / increase dynamic range like the primary Mid/mono channel does, so its spec's are not as good as the primary channel.
2) I wonder what the fig-8 polars look like. There is some spacing between the Side channel elements.. and its seems it is formed using omni MEMS (see TS technical discussion about creating a fig-8 pattern using two omnis here-
https://taperssection.com/index.php?topic=207169.msg2426801#msg2426801). It may share some similar polar attributes with the fig-8 patterns achieved by the Octava MK-12 and the Naiant X-8, both of which use back to back elements that are similarly spaced apart somewhat, except those use cardioids rather than omnis.
My suspicion is that the Side channel polars and other Side channel specs of the Instamic are good enough for effectively "stereoizing" the primary Mid channel, but whether the side channel is sufficiently good for use as a primary channel in a Blumlein array remains open to question. I've only found one or two brief examples of the stereo output from one of these units so far, which sounded promising yet insufficient for making any definite conclusion. For years I used Naiant X-8 as Side channel and was happy with it in that role. I have two of them but have only employed them as Side channels, never tried Blumlein. The spacing between the capsules of the X-8 does appear to be tighter than the OMK-12, and the Instamic spacing may be somewhat tighter still, but would need to measure to confirm.. and there's the whole fig-8 from a pair of omnis thing on top of that.
3) Tolerance of the clock sync between units. The two fig-8 stereo channels will be recorded to two separate devices. Datbrad's use of two mono units in stereo proves the clock tolerance sufficient for achieving good spaced / baffled omni stereo, but that's less demanding in terms of absolute clock-sync than a coincident stereo arrangement where phase needs to be closely matched and maintained between the two channels. Easy to achieve in a single unit doing stereo, sharing the same clock.
If it does work well enough, the two omni (Mid) channels come along for the ride and may be very useful..
1) Although not true Blumlein, mixing some low-passed omni in should extend low frequency response. In that case, the stereo pattern below the low-pass threshold will become increasingly X/Y cardioid-like.
2) Even simpler, if not low-passed, inclusion of some omni Mid channel(s) should alter the pattern across the full spectrum, pushing it from fig-8 to something further along the continuum extending from fig-8 through cardioid to omni. What pattern you end up with depends on the how much omni gets included. This is a horizontal-only "native ambisonic array" achieved by way of two coincident fig-8s + omni, rather than a typical ambisonic mic using a tetrahedral arrangement of cardioids. That may sound complicated but wouldn't be in use. If it works, simply mixing in a touch of omni would shift the pattern from X/Y fig-8s to X/Y supercards.. a bit more more X/Y cardioids. More still will shift toward X/Y subcards and on toward X/Y omnis, so there is a limit of adjustability, but unlike two-channel Mid/Side the X/Y angle will not be altered along with pattern.
tl;dr- If any one does try a pair of these in Blumlein, try mixing in some of the omni Mid channels to taste.
Octava MK-12
Naiant X-8
Topic: Zoom’s 32-bit float m/s - Instamic Pro Plus C (Read 123495 times)