Thanks to everyone for input on appropriate practical solutions for this application as well as discussion the conceptual aspects involved.
I certainly like what I’ve heard of recordings made with Schoeps MK 4V & MK 21, and I have two pair of Microtech Gefell microphones I’m currently using in other positions in this setup, although slightly different models than the one John mentioned. All these including the Senheissers are excellent suggestions I’d love to try, but unfortunately cost prohibitive given the secondary roll these will be playing in this array.
Thanks for the reminder of the Line Audio CM3, which is in a more appropriate price range and which I’ve been interested in but had forgotten about.
Yes, I have a Tetramic, but it’s not what I’m looking for in this application for a few reasons: it is restricted to coincident patterns rather than the spaced A-B configuration this setup is using, it requires 4 channels, and requires separate decoding. I’m using this as part of a spaced configuration surround recording setup which is in some ways the opposite approach to a single-point ambisonic approach, and this setup is already complex enough without those extra channels and decoding steps.
Later I’ll post a few more thoughts on the conceptual aspects. For now, here’s specifics on what I’m doing-
These are to serve as part of a multichannel rig (currently using 6 microphones) which I use for recording performances in good sounding outdoor environments. These microphones will be used for rear-facing ambient/surround channels in an Optimum Cardioid Triangle + surround array, for both multichannel surround and stereo. Here’s a link to a page describing the standard 3-channel OCT setup at the
Schoeps website and
DPA websites and a brief description of OCT + surround (the surround part is the job of these microphones) on the
Schoeps page.
The Gefells I’m using in this array are a pair of M94/MV692 cardioids and a pair of M210 supercardioids, and I’ve been very pleased with the performance of both pairs. One M94 is used as the forward facing, center cardioid. The M210s are used as the sideways facing supercardioids. The other single M94 is currently being used as a single rear-facing audience/ambience cardioid in back, basically mirroring the front center. Rather than that single rear-facing microphone I’m looking to emulate the OCT + Surround setup shown at the Schoeps link with a spaced pair, which was motivation for this thread.
Also part of this array currently is a pair of wider spaced omnis, about 6’ apart in the same plane as the OCT supercardioids. They are intended partly for extending the low end response of the directional Gefells, as well as for ambient pickup and alternate uses as surround channels. All six microphones currently in use are being powered by and recorded into a Tascam DR-680.
It is interesting comparing the contribution of the omnis against the single rear-facing center cardioid. When routed directly to the surround playback channels rather than as part of a 2-channel mix, the omnis do a really excellent job, except for picking up a bit too much direct sound from the front. To avoid pulling the front image around into the surround channels, the playback level of the omnis needs to be lower than is would otherwise be optimal. The single rear facing M94 provides sufficient isolation from the front allowing is use at higher levels but is lacking in low end response, and as a single channel it provides a more limited sense of width and envelopment and none of the nice reverberant decorellation.
The omnis are especially natural sounding, but require riding levels to bring them up to their optimal level between songs and in the quieter musical sections, then down in level when the music gets louder to keep the image properly anchored in front. Similarly in a stereo mix, the greater isolation allows use of more ambience while retaining a cleaner mix.
I’ve working on two versions of this setup. The “no-holds-barred” version is this one, using the full-body Gefells.
I may replace the omnis with backwards facing subcardioids (remains 6 channels). Alternately I may replace the single rear facing center cardioid with this rear facing spaced pair pretty much like the standard OCT + surround setup but with the extra omnis (7 channels) or even increase the channel count to 8 and try it include them all. Then after running it a few times I can whittle the channel count back down to what I find to be most essential.
The other version of the setup uses the same spacing and configuration, but substitutes miniature, less costly, low-voltage microphones for the Gefells. I haven’t yet fully configured that one as an OCT + configuration using side-facing supercardioids, but have used it only as a 4 channel version with the spaced omnis + front/rear facing miniature supercardioids.