I've tried using the Schoeps Image Assistant app and I'm ashamed to say I can't make heads or tails of it. I don't blame the app...this just goes to show my own limits
It's not intuitively obvious what the Image Assistant display is communicating. The
SengpielAudio Visualizer is more intuitive, but more basic and incapable of modeling 3 channel configurations.
Image Assistant main view screen works basically as follows-
The horizontal axis (abscissa) indicates the physical recording geometry side of things. Center of that axis, marked as 0-degrees across the bottom, indicates an angle facing directly forward as in looking at the middle of the stage. Angles extending leftward and rightward are marked in degrees across the bottom, extending out to +/-90 degrees / 180 degrees total. The Stereo Recording Angle is indicated by the shaded area across the center, denoting an imaginary "window" as viewed from the recording position, through which sound source positions making up the sonic scene will image between the front speakers upon playback. Sound sources outside the shaded area will either be reproduced as emanating directly from the left or right speaker (stuck to the speaker positions) or reproduced diffusely. The more-heavily shaded center portion shows the 75% SRA point, which you can ignore for the most part. It becomes useful not for assessing any singe setup but for comparison of setups, since most of the variation between similar setups will occur outside the central region near the periphery.
The vertical axis (ordinate) indicates the playback image "perceptual" side of things- Line segments reaching the top of the vertical axis indicate that upon playback the sound is heard as emanating directly from the right speaker location; Line segments reaching the bottom portion of the vertical axis indicate sound heard as emanating directly from the left speaker location; The mid-point on the vertical axis indicates sound reproduction from the phantom center of a 2-ch stereo speaker array, or from a center speaker in a 3-channel L/C/R playback array.
The most accurate microphone setup in terms of the translation of source positions to playback imaging positions would be indicated by a straight diagonal line running from the lower left to upper right. The angle of that line denotes the recording angle of the setup- a steeper, more vertical line indicates a narrower SRA or acceptance angle, useful when the recording position is further away. A flatter, more horizontal line indicates a wider acceptance angle or SRA. In either case sound will fill the space between the two speakers upon reproduction- notice that with all setups, the lines reach both the top and bottom of the display indicating the sound emanating directly from the speaker positions. However, also notice that different setups extend more or less widely horizontally out from center before intersecting the top and bottom edges, and that shaded center area indicates the inclusive recording angle or SRA of the setup. All sound sources located outside that area will be reproduced as if they were crushed into the speaker on that side, or reproduced diffusely, depending on the diffuse-field correlation of the particular microphone setup.
Anyway, the reason I was messing with it was to figure out the viability of replacing the center card in on OCT2 array with a supercard. Would this allow for narrowing the spacing of the side-facing supercards because of the increased directionality of the center supercard?
More on this tomorrow, as I'm out of time now. To start:
With 3 channel arrays, the diagonal line in Image Assistant is broken into two parts a Left-Center segment and a Right-Center segment. By adjusting spacing/pattern/angle (and level/timing as well in some advanced setups) one tries to get the two separate segments to form a single diagonal line..